We all know that heat rises – and for the same reason we know that loft insulation is crucial to energy efficiency in the home. But how well do you really know your loft? Can you even access all of it? Even if you don’t have a loft you still need to insulate above your head!
A lot of homes have a typical ‘cold roof’ where the ceiling is flat and the loft filled with insulation – but how should you do this right? Many homes feature extensions, often built in the 20th century without much consideration to energy efficiency – so they can be a major source of heat loss.
In this talk, Ben Nother and David Copeland and from ecological design and build company Hawkland explain your options for insulating these typical problem areas including a discussion of what materials to use in what setting.
Find out more about Future Ready Homes here: http://futurereadyhomes.org.uk
Find out more about Hawkland here: https://www.hawkland.co.uk
Find out more about The Green Register here: https://www.greenregister.org.uk
Find out more about Marches Energy Agency here: https://mea.org.uk
Find out more about Severn Wye Energy Agency here: https://severnwye.org.uk
Find out more about Herefordshire Green Network’s Building Sense here: https://hgnetwork.org/about-building-sense/
Welcome to today’s event I am gentan Cartley from Herer green networks building sense Group which is an initiative that was started in 2020 to bring together people information and professional expertise to help with the challenge of making homes comfortable year round in the face of both High heating bills and of course cutting
Carbon emissions um today we’re delighted to be able to host this webinar on behalf of the Future Ready homes program of which hgn and project Partners um and with the support of the green register who since the year 2000 has trained thousands of construction professionals from all disciplines the industry to build better
More sustainable buildings a tiny bit about futur ready homes for those that don’t know what it is um it’s been running in shopshire Paris and Herer since early 2022 um and being delivered by marches and seven wire energy agencies with the support of groups such as ourselves hdn
In Herer light fet in Po and zero comire in shopshire um the main focus of the program has been to promote and support good practice energy retrospect across homes in the marches area um and doing that through webinar series while we’re here today retrofit advice fully funded home retrofit surveys and plans which
Unfortunately have now all been snaffled um and events like green doors which has just concluded um on that note of fully funded home retrofit surveys though I will just add in now if you’re in gler share which I believe they might be a few of you um I think through s y energy
Agency there are some fully funded um home surveys around so I will forward you details about that but I just wanted to pop that in there now um so yeah I’d also like to take the opportunity to thank all of you that have given feedback to us on our past
Webinar series um and on your retrofit experiences to date it’s really really appreciated and it is very valuable to us right now uh future homes is Du conclude in at the end of January but we are applying for more funding to see if we can continue for another two years um
So yes your feedback is really really important to those applications so that all aside um I can now introduce our webinar and speakers uh today we have got ecological design and build company hawkland returning to us after their much acclaimed initial webinar on how to retrait the traditional terorist home a
Few weeks ago um today we have Ben no not an um sorry Anna as some of you might have been expecting um and he is here to talk to us all about how to insulate those tricky but essential areas over our heads flat roofs sloping ceilings door windows and the such like
So Ben thank you ever so much for joining us and I will now hand over to you thank you very much J I just uh share my screen over here hopefully that’s all coming through for everybody um yes thank you very much um I suppose small bit of housekeeping
First yes it was meant to be Anna she’s unfortunately had to whip over to the us for the rest of December uh so I stepped in um to deliver the presentation today uh I will uh begin so a little bit first on uh on ourselves on hawkland um we are
A bristol-based um architecture and construction company um who use mostly natural materials but appropriate materials um in low carbon retrofits and and new builds as well we do a lot of straw baale uh new built um trying to utilize uh developments latest developments in sustainable uh design and Technology as
Well um that’s the three of uh us directors David who’s joining me as well today um uh and also Chris who if you come through to us for any initial inquiries you’ll get one of the three of us first um our architecture team is myself uh Anna who is our architecture designer
Amber who is our architect assistant and Michael howlet who we use um for uh our straw Bell projects as a technician as well uh it’s just some of the projects that we have worked on uh but for today uh how to insulate brues flat and sloping seats so we’re
Going to cover um our retrofit approach principle around why we do a retrofit sort of holistic h house approach um have a look at why you might want to uh insulate or or renovate your roof itself looking at Material choices um including sort of u values and buildups and things
Um and considerations and interventions for roof and then we’ve got a few case studies of projects that we are working on currently um and ones we have uh recently finished so all of these projects will be from this year um and all around um upgrading
Roofs uh so as as an approach as a company um we try to uh uh working them in a as alistic as a way as possible um looking at the whole building once we get a lot of inquiries for maybe individual interventions into properties whether that is just the
Upgrade of a roof or an extension on the back of a property we’ll talk to our potential clients about the the whole of their house and see if that’s things that they have kind of considered whilst looking to put budgets towards certain projects uh uh and certain upgrades to
Their property having a look at what might best uh be best appropriate for each property on an individual basis uh we use research and and evidence based uh uh designs um standard details um material approaches and and Technologies um and obviously everything is very budget dependent so we get a lot
Of projects or a lot of potential projects which come to us which might start out as one thing but slowly evolve into uh something else or a different set of Works which are slightly more appropriate than what they sort of the client first thought um sort of the reason why we
Look at whole house ructure fit um is because of uh kind of moisture movement throughout properties uh insulation firmly upgrading uh uh the different sort of elements of the building uh air tightness as well and with air tightness and this insulation upgrade ventilation um how all of those sort of need to be
Looked at um on a a whole house and how sometimes one intervention may make things potentially uh uh um not necessarily worse but they might not have the impact that you’re looking for because other elements haven’t been uh considered so inappropriate interventions um they might be things like poorly installed Windows uh just
The maintenance of properties as well being poorly maintained um Outlets ventilation voids within properties which might stop things being as airtight and might have unregulated air changes sort of in a property um inconsistent uh quality throughout the different buildings whether that’s with in extensions or Loft conversions and
Things like that being put on which might not be as appropriate for say period properties um different sets of material buildups throughout a property as well um can you know bring up sort of cold areas they might make certain rooms worse once other ones have been uh
Improved um you know then producing poor uh indoor air quality uh peeling wallpaper mold leaks damp those kinds of things uh so one of the first things to touch upon uh um is materials so we use um a lot of wood fiber with our insulation projects and whether that’s
Sort of in in walls whether that’s on uh uh sorry in roofs or on walls or in floors we have a look at as sustainable uh and natural materials as we can possibly get into our interventions so things like wood fiber U which have sort of low voc’s they come from sort of
Recycled materials um so we can consider the sort of the life cycle of a product basically rather than just coming in putting something in and then it sitting there for however long and having no thought to what then might happen to uh that material if an upgrade uh then is
Done in a few years time um we like wood fiber because of its uh um sort of benefits so you can see from uh uh some of these or one of these images uh sort of the carbon impact of some of these uh insulations you know the carbon impact of the
Extraction how they’re actually manufactured and produced um transported to SES and sort of in their use as well um and to to go down to the bottom of that image on the right um where we’ve got sort of wool uh cork hemp crats straw bales these are all the materials
That we as hawkland try to employ on our uh on our upgrade Works uh looking at a little bit of uh comparison um for materials themselves so things like sheeps wo has a very low global warming potential as does wood fiber whereas p is quite high in its
Sort of use and Manufacturing um and then on the the other side sort of the resource use itself um again wood fiber is quite low in comparison to some of those uh more manufactured materials uh for anyone who is looking to do some of this research themselves
Um there are lots of places that you can go to kind of get ahead of this uh look at all these different materials and um to allow you to make better sort of considered uh um sort of more considered choices I suppose within the materials that you’re
Looking to put into your buildings so the construction material pyramid um has a bunch of different materials and it will give you a lot of good information about those from sort of the CO2 that’s produced from these sort of materials uh and how they all sort of Stack up against each other as
Well uh other benefits then of why we use wood fiber um over some of those other materials um good acoustic properties uh it’s very robust and has a a good sort of speed um of application which means that we can get sort of more work done quicker I suppose um so if
You’re looking maybe not necessarily for DIY but more for someone to come in and do this U um sort of wood fiber whether that’s sort of uh various manufacturers um the more um uh sort of board or B type uh uh insulations um are equivalent
To you know P boards in terms of sort of their their actual application and installation as well so you don’t lose time on installing natural materials um you can and the way that we like to do uh um sort of things uh when we come in and install stuff you might spend a
Little bit more money on a slightly more considered contractor who would come in and not necessarily just Place insulation in between sort of Rafters or joists and things like that but actually look at the Junctions between various elements and we’ll talk more on that sort of uh throughout um but there is a
Speed of application but with that and with a more considered um set of materials and details um there is a little bit of extra time spent just to get those right you know taping in the right places and those sorts of things Uh Wood fiber as well um
Obviously has good sort of uh um life cycle to it as well being sort of recyclable um as do many natural insulation materials uh so a little bit on u values to touch on um these are General u values that you need to achieve for
Either sort of new uh uh um elements um upgrading elements in existing dwellings um we won’t touch much on these but that’s part of the sort of the partel document part of the building regulations uh that you would need to look at achieving and um there are some
Resources to be able to do that so there’s sort of free online U value calculators which will allow you to sort of see what thermal performance you’re getting these are quite um uh what’s the word I’m looking for they’re kind of not practical necessarily this is very sort of uh um
You know desk based in terms of their application because they don’t take into account sort of air changes uh how well things like insulation is fitted it’s just a very sort of ready set of information to say if I use these materials Within These sort of
Thicknesses this is the U value I may be able to achieve with uh with this upgrade um and we use um change plan and iacus as well um iacus is a little more uh I’d say change PL is a little more user friendly it’s it’s quite a
Simple uh process to go through to be able to pick things out um whereas this one gives us some slightly better uh images and buildups in details and and shows things just a little more uh in detail and in depth as well so rues themselves considerations and interventions why would you want to
Insulate your roof um typically to improve its thermal performance um this might be uh in uninsulated attics and looking to put insulation in at the sort of the ceiling level this might be Loft conversions where you’re potenti looking to bring a room within the thermal envelope of your building um it
Might be to bridge sort of the performance Gap in certain areas know one part of your roof might have poorly fitted insulation as you can see from sort of the image here where uh someone has tried to sort of stuff mineral wool down between the joists and it’s got
Stuck essentially and hasn’t insulated 2third of that part of the roof um other things which which come around that might be that your your sort of your felter your membrane might be towards the end of the life especially if you’ve got more of the older sort of
Bitrent felt on your roof now um that it might need to be replacing it’s good opportunity to then come in and insulate the this the sort of the roof space um and obviously it might be a potential um uh source of large heat loss in a property um insulating either a ceiling
Or the roof is usually one of the first things that uh that we would look at to try and help a property sort of uh per form along with things like Windows and Doors and sort of air tightness measurements um and you know you can go out to design professionals um I think
As G was saying the at the start there are various people who can have a look at doing sort of retrofit plans or retrofit assessments um for properties as well and that should give you a good list of interventions to be able to follow and uh usually if you’re roof for
Your ceiling isn’t insulated that will be high up on that list as a relatively uh reasonable cost intervention to be able to do to give you a good uh sort of performance boost for the property uh additional considerations uh are not necessarily on the buildups or
The roof itself um but things you might have to consider as part of that is things like local planning policy whether you’re in conservation areas or you have a listed building you know the materials that you can use and how you talk to sort of council departments on
The interventions that you’re looking to put in whether you’re changing sort of external materials and those kinds of things as well um you know going from tiles to something slightly different or or looking to upgrade a roof uh um sort of structurally as well because you might want things like solar panels and
Those kinds of things so changing the actual um sort of structure of the roof as well and getting the involvement of structure Engineers to to help through that um and one of the big ones would be ecology so birds and and bats whether there are any presence of of those and
Getting surveys done early if you’re looking to uh insulate the spaces to make sure that if there is any um presence of of bats uh that you are getting the appropriate license to be able to do the work and that is being done at the sort of the appropriate time
Of year um there’s also then party wall considerations as well so uh any property any neighboring property if you’re looking to say upgrade the structure and you’re fixing into the party wall you need to talk to your neighbor about the work work that you’re doing and get a party wall agreement
Between you and some of that can also happen with insulation you know if you’re looking to do a loft not necessarily L conversion but you’re looking to bring the Loft within the thermal envelope of the property the party will will be a leaky cold space if you’ve insulated your entire roof
Suddenly that’s the cold point in the room so adding insulation to that part whilst it’s not necessarily the roof it’s still part of that space that thermal envelope that you’re looking to improve upon so talking to your neighbor uh uh about um insulating party walls especially in the Loft space as well and
Some of that might come in with other elements like acoustic improvements and and things like that and uh it’s it’s best usually to talk to uh an architect or a design professional to get advice on the other elements of that rather than just putting some insulation up
Onto of on a party W having those other holistic considerations for our our whole property sort of uh taken into count as well so some interventions for the roof uh itself as we sort of mentioned uh um either relaying insulation in the Attic So at the ceiling level um or adding U
Insulation on top of that just to improve the performance is quite a lowcost intervention something a lot of people can do themselves um there are lots of companies out there as well that will do that uh um as a sort of a service for you um but it’s looking at again are you
Storing stuff up in your loft there are considerations about putting in sort of Loft stilts and boarding to make sure that if you are improving those kinds of areas you’re not compressing all of that insulation that it’s allowed to sort of do the job uh that it’s been put up
There for um other elements maybe on the outside of the property would be sort of Checker checking the sort of guttering um and general upgrade um maintenance upgrades to the roof as well and if you’re looking more at you know stripping back the roof taking all of
The tiles off putting new membranes on that allows you to consider every part of your roof um keeping it airtight as well with the with the Loft hatch and and insulating and sealing a loft hatch has a a big difference as well so we’re not just getting air being pulled up from uh
From sort of a landing space or wherever your Loft hat will be up into an unheated space uh more deep interventions would be converting things to uh uh RS uh to warm roofs so putting insulation in and on top uh of the the buildups rather than set the ceiling level you’re doing
It at the rafter level so bringing the entire space within the thermal envelope of the property um uh refitting 4y flat roofs uh whether they need different FS whether you can do that with insulations as well uh um improving air tightness layers either through the sort of at The
Loft level or again up at that sort of RA the level but as part again with any air tightness measures of looking at an air tightness and ventilation strategy throughout the whole building uh and then as we’ve mentioned sort of adding solar panels uh or adding
Mvhr units which might go up into the Loft and if there’s any structural implications which might come with that as well so look at case studies themselves this is where i’ be spending most of the time on this talk um uh with especially with this first
One because we have a project at the moment which is a renovation of the roof but it has multiple different roof types so this project has got a flat roof it has got uh the roof that you can see on the left hand side is a pitched but
Vaulted roof the slight pitch you can see on the right hand side is not Ved it has a ceiling into the room below um and uh and just behind us on the right hand side there’s also a monop pitch volted uh roof too so it’s got a lot of
Different buildups here and we develop drawings to have a look at how we can consider each of those uh different roof buildups so whether we’re upgrading a uh sort of a flat roof or being able to put uh insulation then in between the rafters of a volted roof and again on
The bottom one putting Insulation at the ceiling level as well so this project has got multiple different roof upgrades going on with it uh all of which um no not true not all of which um as you see from this drawing type one and type three both being insulated from the
Outside so the flat roof on this project has been entirely stripped back and we can insulate from the outside because the client was very keen on keeping all of of their ceilings because they’ve been newly uh sort of boarded and plastered and it was work that they had
Done uh not too long ago whereas within the sort of the type one uh sorry the type two roofs being able to um do that from the inside so taking down boarding on the inside of those vaulted uh uh roofs rather than taking them off from the
Outside so with this one it’s an existing cold roof but there’s not much insulation in there not enough to be making an impact so we’re looking at upgrading that with more Loft instulation said from the the previous slide so that’s type one which is down the bottom so they’ve got a little bit
Of insulation within the existing ceiling joists and we’re looking to lay new insulation within that but put insulation up on the top as well um that one’s an inaccessible roof which is why we’re doing it they don’t have Loft hatch which why we’re doing it from the outside for that
Roof uh that is this kind of detail this kind of buildup um which allows us to either just put some flexible insulation in between the rafters and potentially lay flexible insulation on the top or to put a board on the top something a little bit more rigid um again to be
Able to allow not in this project necessarily but in other projects uh a little bit better storage if we’re using slightly more rigid materials going in uh this is a buildup that comes um specifically from styo uh that isues 0.14 um as a thermal connectivity uh as
A u value to uh the ceiling level um this is the one where you have a slightly more uh uh solid board on the top um which allows a um as I say you’re putting down a sort of a deck first so you can have access you can store sort
Of things up there rather than say if you were to put sort of mineral wall or sheeps w or something like that uh uh which doesn’t want to be compressed um sort of the wood fiber insulations allow us to work within certain depths and certain thicknesses without having that
Issue with with compression uh on the insulation themselves so this buildup would have a structural deck on top of the um existing ceiling um it’s always wise to check with a structural engineer as to whether your existing ceiling is suitable for uh you know storing stuff on there as well
So this is the current flat roof we’re working with you can see poing on it already um this has already had an intervention several years ago uh where they installed insulation on top of the existing uh roof so there were several layers to get through when we did this
Um and um sort of the moisture issues from just having drainage as you can see in the bottom left of this image uh the the guttering in the drainage terminates onto this flat roof and then is taken inside through the building um which brings us to sort of damp staining
Internally uh where uh um where there’s been leaks or where things haven’t been sealed kind of correctly around uh sort of drainage terminations and things um that’s the the drain itself it doesn’t go into anything it just goes into a hole um on this roof um and you
Can see on the right hand side there’s the level of layer of insulation that was just put on top of the existing roof so uh this was a very hard roof to cut through um there’s a layer of bitman on the top the insulation which came up
Okay but then a layer or three layers of bitumin uh then on top of a Timber deck which was on top of the um existing roof that’s what it looks like um not currently we’ve moved on from that a couple of weeks ago AG go um this is it
Being sort of stripped back um on the right hand side you can see that we have to consider Falls even on a flat roof you’re always considering how moisture will move away on a roof as well very easy with pitches with flat roofs we have to look at exactly what those Falls
Will be things like um Timber furring strips or even cut to Fall’s level of insulation uh which might be appropriate put in to produce those fools um this one’s a little bit more difficult it’s got some clear story windows down into the living space where we have to
Consider how we are um either ventilating with a with a roof buildup or uh just protecting from uh moisture as well so this is a not necessarily a new roof buildup we’ve got a slightly different buildup for this uh that we’re employing on this roof um but this one
Is again another standard detail from a manufacturer to achieve a a u value that falls within building regulations um this uh uh flat roof buildup puts insulation in between the joists which is something we’re doing it also puts insallation on top of that so under the new building
Regulations as of last June um you have to consider things like thermal bridging so it’s not sort of just adequate to insulate only between the rafters now you have to have a look at how you are stopping cold bridging through those Rafters through those Timbers and the
Potential to put insulation board on the either inside or if you have the opportunity to the best places on the outside of those Rafters um to stop that that thermal bridging as well um and this allows us especially with a slightly more rigid um insulating sort
Of a sheathing insulating board um to uh get in sort of the ventilation layers that we would need to do um this detail has a metal roof and I think you always have to ventilate a metal roof um because of where the duw point and where moisture builds up within the roof you
Have to get that that moisture away so it always has to be ventilated um we have been talking with back to Earth um who uh um have provided support um um to us looking at things like woy modeling to see where moisture builds up within roofs um to have a look
At what they are calling a compact roof so this is that warm roof it’s the same as the previous buildup but without the uh ventilation layer um and uh I uh I was a little bit worried about it at first I like a ventilation layer um it
Allows us to pull moisture away where needed but with the buildup that we have here and the discussions we’ve had with back to Earth with wood fiber we’re able to push the moisture away enough that the wood fiber is able to deal with it um critical on this on this detail is
That we have what’s called a variable uh air tightness membrane as well a normal air tightness membrane wouldn’t have been suitable for this buildup and that’s this is called a compact roof buildup so because we’ve got limited uh uh working room on the flat roof on this
Project we’re able to come in with something that’s slightly Slimmer um to be able to put in but this is um you know a slightly deeper intervention this is a a we’re able to take the roof cover off and work from the outside back in filling in and building back up so we’re
Kind of taking away but building back better essentially uh to use a government’s term uh this then is the uh uh sort of the final roof on this project uh where we will be working from the inside um this has sort of moisture issues um they aren’t necessarily just
Because of the roof it’s to do with how moisture moves around the property um you can see lots of peeling um paper on here this is a slightly volted ceiling so uh moisture is able to rise up towards where there is a weaker point which is sort of the clear story windows
The Junction with the roof as well um at the moment we haven’t opened this one up yet we’re just working on the outside roofs at the moment before uh before the sort of the winter break um this is something that we’ll get back to sort of in January February kind of time getting
Back in uh working from the inside to insulate these um this would be an ideal buildup for that voled ceiling so putting insulation again within the uh inside of the rafters in between the Timbers and then an insulating board uh internally and externally so whether you’re creating service voids internally to
Allow uh pipe work to allow electrical runs um either in your ceilings or your walls things um being able to insulate and then provide a service run again just helps with that cold bridging just stops the uh the Timbers from being the weak point in that buildup and again as
I say ideally on this pitch um you’d have some insulation on the outside as well as a as a sheathing board this then is um again would have to be probably done from the outside as you’re sheathing from the outside but if your membranes are starting to go so the
Bitamin Felts or any breather membranes that have been sort of Applied um and are coming towards the end of their life um by raising the or or putting some insulation on the outside you’re you’re still coming in insulating you don’t get that disruption that you would have if
You are insulating from the inside taking down uh ceilings um especially if they’re older and they haven’t had any interventions done if they’re LA and plaster ceilings is a very dirty job um and is probably one best done by someone else and not yourself because it’s a horrible horrible job I know because
I’ve done it um so sometimes going from the outside just has that less disruption to it and will allow you uh uh um to obviously use the space still whilst that work is happening but there are then things like planning considerations you’d be raising the roof line potentially raising the
Ridge as well by building up the insulation on the outside uh and what we have for uh our buildup is um a buildup where we are only part filling the uh uh the joists basically um where we have to maintain a level of ventilation through this
Buildup as well so trying to maintain 50 Mill ventilation above the insulation to pull moisture away so it’s not the same as the compact roof which we’re able to do with the deck and insulation uh um sort of on on the outside with the um EPDM membrane that we’re looking to put
On that one this is a a til roof go back to the first image so it’s it’s that tiled roof um where we have to maintain the level of ventilation to to pull up through uh this is a project we worked on recently um where it was done from
The inside um we uh came along and insulated uh in between the joists um and have then appli a sheathing board but um the the prop passive uh board which acts as the air tightness layer just gives a bit of rigidity to the uh uh um to the roof as
Well and sometimes when you’re upgrading uh elements especially if you’re having to take out potentially take out some structures things like pearlings and and and elements like that how your roof maintains its structural Integrity also has to be considered so um we use things like sheathing boards all agreed with
Structural Engineers um as well and on the right hand side you can see where we’ve battened off for a service void with some uh conduit sort of running through as well um so the one on the left hand side is this is the roof just from two different angles the first is
The one where it’s been insulated and then secondly where we’ve applied the board and the service void uh this is then the same space um after we have uh boarded out with plaster board um using um a service void allows us to use plaster board it’s not
A very nice material but it is one that does a very good job um but having that service void doesn’t um sort of affect the moisture movement or or doesn’t detrimentally affect the moisture movement let’s say um and allowing that roof buildup to deal with moisture and
Um um uh and how it works by not penetrating through sort of the air tightness membrane too many times with plastic W no those kinds of things so uh the second case study we are always looking at changing kind of how we not necessarily insulate but how we’re detailing and trying to
Employ the best kind of ways to uh to detail whether that’s with new materials or new new um Technologies um this is sort of a a warm roof buildup and it’s one that we are just using on a project that started today to uh um thermally insulate and bring in
A a loft space into the thermal envelope so it can be used um as a bedroom and how we might you know with option b might have only just insulated um on the tops or internally to the um to the Timbers um to maintain things like ventilation gaps underneath tiles um but
We have opted for something more like uh uh option A Where We Are battening off and sort of boarding or slatting out so we’re stopping any of that new insulation that we’re putting in between the joists getting up into that insul uh into that ventilation void so we can maintain the ventilation pulling
Moisture away uh up through there and again putting a board on the inside as well on this buildup um to assist with that cold bridging uh this is a similar buildup um but as you can see with yacus um you get a nice detail buildup through a a roof
So we’ve been able to put in to see what kind of level of of thermal performance we can achieve so whether we’ve had to deepen Rafters um because generally insulation which is uh um more flexible the insulation BS the the ones that you saw on the left hand side there
Have a slightly better thermal conductivity than the boards themselves so the more rigid boards s uh these ones that would be sort of on the top um only very slightly but the more you can get in between your joists the more flexible installation you can get in between the
Joists the better the the U value will be the better the thermal performance will be generally of um of that new buildup so this one here is just sort of fully filled almost uh with new Timbers put on the inside to frame out um a little bit to better within uh this one
Doesn’t have that additional layer for uh considering cold bridging here is um similarly one which we did again this year um where uh another contractor actually built the roof itself and we came in to do uh some insulating work with natural wood fiber uh insulation so this is it’s being
Fitted on the right hand side up in the flat roof and then uh the image on the right hand side where we’ve over or under boarded U with a sheathing insulation board and then on the left um with a membrane fabric sort of membrane this time to get our air tightness in and
Around uh that property and then case study three which is probably a very scary case study is rebuilding a roof entirely um mentioned Structural Engineers several times before um invaluable on this project where once we started to strip back the roof uh we found which was inaccessible
Uh on sort of first uh uh sort of uh times that we were looking at it there was a crack in the Ridge and there was a little bit of degradation in the hip on this roof the the sort of the the top rig and the top hips that you can see on
That um sort of towards the top of the image um which basically meant an entire new roof what that did do was it allowed us to employ some of these techniques and different ways of insulating the roof so it wasn’t necessarily just take the boards off or or or have an exposed
Uh roof build up which this was at first it only had as you can see it only had Insulation at ceiling level um but they wanted to bring the ceiling or the the the kind of the Loft space uh into a more and a better storage area because
All of their stuff was getting damp and moldy up in the Loft so they didn’t want that was a small property didn’t have anywhere to store anything The Loft is the ideal place to do that so by bringing the Loft into the thermal envelope we’re able to better control
The humidity the moisture and the the thermal performance of that space uh this is the new structure um it was an awkward build because of where structure had to be um single skin walls which weren’t great for bearing anything on so additional Timber structure which
Had to go through um and this is the detail of that so insulating in between the rafters little bit of insulation more for AC actic and fire performance at the ceiling level um but building up new wall plates putting on new Rafters putting on new floor joists to make a
Better and improved deck um we employed two membranes on the outside as well um something we haven’t touched upon won’t getting too much into sort of the technical side of things on this is that sort of wind draw from um from sort of insulating uh elements so where you do
Have that ventilation Gap um we’re finding now that actually if insulation has been fitted sort of poorly or in the gaps in between a Timber and then the insulating layer air can get up around there and that is where heat will be pulled through so almost creating a
Cassette almost like a sips panel um as a sort of a new design to try and mitigate against some of those sort of factors as well um and with this one we did have an insulating board on the uh on the outside very thin uh insulating
Board on the outside as well but we were because we were re building a roof we were able to maintain the ridge Heights and tile Lin which meant that we didn’t need to go through to planning because we weren’t changing any of the external kind of appearance um outside of things
That we were allowed to do under permitted development so this is then the overboard um roof itself um with a an air tightness layer to stop that draw to stop that pull of the uh the the Heat through the buildup uh this is it then with um its
Secondary layer of uh membrane on acting as its weather proofing um and then tiled as well as a finish so to round out all of that um for people who are looking to do things themselves potentially there’s lots of resources that you can look at um there’s the Builder book which gives uh
Good sort of details or problems to avoid at least with this and then maybe what to to do on how to actually detail between Junctions you know it’s not just insulating your roof it’s making sure that you’re not getting any cold points sort of between the top of your wall and
Your ceiling level or the bottom of your roof and how you might uh both ventilate and insulate sort of at those Eaves kinds of levels that takes you through a bunch of different the buers but bunch of different details um to to have a look at um there’s also the sustainable
Renovation which looks again at a whole house kind of Ovation um details around not just roofs but sort of walls and floors and different strategies that can be employed if you’re looking to use um wood fiber specifically the wood fiber insulation Academy gives more information on that uh and then the
Retrofit pattern book itself uh provides more uh robust details as well you have to sign up to the the retrofit pattern book as well to be able to see some of those details and they are the details themselves uh are much more like the details that I presented you know where
We have this kind of drawing so it’s always worth speaking to a design professional first before you kind of embark on any of these uh um potential upgrade Works uh because even if you are looking to do them yourself it may be that you want a set of drawings or a set
Of information even if it’s being told which detail in the retrofit pattern book might be the most appropriate um finding someone who can pass all of that information and understands it to be able to sort of relay it back to you is a good first step before just taking
Things down and starting to insulate uh thank you everybody uh for listening lovely thanks very much ben really really interesting um yes Jackie has just asked that people put their questions in the chat please um so please do that um and I know David is keeping an eye on that um actually there
Has been a question that’s come in sorry I’m just jumping in um but it’s because I was going to ask it as well and it’s about what do you do with Dormer windows and particularly where you’ve got limited depth um so yeah I’m just going to Chuck that out there and then I’ll
Stop interfering uh Dorma windows are very hard to sort of uh uh renovate because you either have to take off from the outside and put some insulation on the outside of that dormal window which might not be possible dependent on where the you know Top Line of your room
Finishes you know and how close to the tiles they get um especially if you’ve done something or something’s been done under permitted development because you don’t want to change those levels but you can look to put in small planning applications or householder planning applications to change the heights if
You have that um the other thing to do would be to it depends on when it was built because you know if you’ve if you’ve had it done two years ago you’ve probably out of natural materials you’ve probably got a good level of insulation in there between the joy and the
Insulation that you might replace it with might not be any better performing so the only other thing to do would be to come into the room itself which with a lot of Lofts very difficult to do without affecting that head height um there are better let’s say better thermally
Conductive materials that you could look to employ necessarily natural ones um but if you’re looking more for that sort of natural approach um uh uh uh it’s probably someone coming out and measuring a lot to see where you can fit that insulation essentially um or going
Great it’s a you know making a big hole in the ceiling saying well it’s a mineral wall we know that we can get a slightly better performing insulation to put in there and replace it with yeah brilant thank you dormas we’ve done a couple of dormas um or Dormer
Windows as Ben says maximize the insulation as much as possible otherwise probably looking at air tightness and um the condition of the window reping the window especially if they’re old um windows and normal Windows um but very very tricky spaces very tight very small um and very very difficult to do um but
Your sort of your yeah lower intervention would be S like a secondy double glazing or replacing the windows look at the air tightness at that Junction um and then upgradeing insallation where you can um but I don’t know if you can see the chat now you’re
Sort of um available they’ve got a few questions coming in oh um I might have to stop sharing my screen that’s right don’t worry I I’ll run through it then um I can bring up slides if they’re appropriate as as necessary as well PL ability concerns on natural insulation
Um they’re generally treated they usually they will all have fire um certificates um sometimes we can be restricted as to where we use them when we have particular fire requirements um where we have to we just got no choice but we have to use uh fireballing and
Stuff stuff like that um but the use of them when outside of that um are all fine um I don’t if you got any comments on that one Ben from your perspective uh I I I mean again Fire strategies and things are something that we should be always
Talking to design professionals about so when you’re looking at things like party walls um whether they want sort of acoustic improvements but fire is a big thing to consider as well and generally uh something like uh um again depends on the space that you have to use and the
Buildups that you can you can do you know if you can insulate with a natural material you might look at using a fire board or something like that you know a plaster board to protect between compartments and things rather than say using a rock wall or a buildup in that
Sort of sense which has a better uh sort of fire protection uh um with that but generally with um is it permeability as well um that was that was mentioned um it’s why we look at things like service voids as well so we’re taking any of those impermeable materials like uh uh
Plaster boards and things sort of out of the equation by allowing that bit of ventilation up behind in a service void that lets the natural materials kind of do what they need to uh um especially with membrane you know appropriate membranes and things within there as well yeah I think in sumary basically
All products will have testing it’ll just be a level of how good they are how long they can last there’ll just be some scenarios where we are our hand is forced is what we can use um but if whatever product you’re using um you should always be able to find their fire
Certification and performance um and we’re getting a lot more materials and products out there at the moment now as well which is brilliant you know 10 years ago there’s a a far fewer tested and certified products in the natural material space um question on metal roofs and air
Gap if it’s laid directly on top of a felt roof does this create an issue because of uh dpoint um I guess you got potentially yes um it depends what is insulated in between the the joists or the the sort of the rafters um if it’s a
Sort of a bitum and felt it’s probably better to remove it and um if you’re overboarding let’s say if you’re putting an insulation on the outside um you you would have that opportunity you’d have to be removing the tiles and the Baton anyway so you might you know refelt uh
Or REM membrane let’s say the the roof um and uh and insulate it that uh level I guess if the the waterproof layer is is decent in decent condition underneath the metal that in itself should be one fine there will be moisture because you get quite strong heat fluctuations
Underneath the metal surface um as long as there’s good air gap and a good ventilation and cross and the movement of air through that should dry it out yeah with with metal Ro specifically um they they have to be ventilated because the metal gets so cold basically and
That’s that’s where all of the the the sh point will be so they’re ventilated to be able to pull that away uh question on attaching BS internally without punching membranes causing thermal bridging uh two sort separate points there um when fixing fiber boards or other boards in on the inside of
Remembering it will punter it this is generally deemed as okay unless you remove that screw um or fixing and then put it in a new place so when you’re um so trying to calculate the likelihood of your air tightness performance on a passive house you know you’re going to be punching membranes as
As you install it it’s generally de that once you fix it in you essentially create that punch but you plug in it with the fixing that should be okay um no house is 100% airtight um but generally like with a passive house standard you know you don’t want
Anything more than the equivalent of I think about a 10 P piece of total air leakage throughout the entire building which is a very small amount um so basically if you fix in once you leave it there in terms of thermal bridging a lot of fixings that we usually get are
Thermally broken so for example there’ll be a metal screw within a plastic plug um slightly different if you’re screwing into Timber and now go straight into Tim and there will technically be a thermal bridge but there should be relatively minimal on the entire buildup um depending on what specification you’re
Going for these will be calculated or or not sort of included in the calculation and kind of on that it’s to do with sort of percentages and there are allowable percentages that you’re uh kind of allowed in terms of me you know every member will potentially have a slightly
Different percentage that it can be penetrated into um and again when you’re doing sort of thermal calculations you value calculations and those kinds of things we look at the percentage of say timber to Insulation at that level and then what we’re putting on sort of over the top the percentage of screws that
Might kind of go through there so those kinds of things should be calculated as part of um you know a u value uh calculation to see what the performance of the the the the the new buildup would be um and that might make you have to reconsider say thicknesses and things
Like that as well just got if you could just um possibly stop sharing your screen Ben yeah now we’re done um we got a few more questions um then allows you to see the chat if you want to as well um got one here from Joanna um I have air bricks
Just below sofit level in a 1950s Bungalow are they there to sorry things in the way are they there to ventilate The Loft oo uh maybe I would probably think they’re more there to ventilate the wall if it’s a cavity wall um you might have abs at
The bottom you might have abs at the top to have that flow up and through um without having a look I’m sorry I can’t say much more than that without being able to poke my head into your roof at your sort of Eevee level to to to have a
Look down to see exactly what’s what’s happening uh um some of that might be closed off you know there might be uh Timber wool plates on top of most to be able to take the roof which would sort of stop things from being able to sort of ventilate up which would suggest if
There’s air bricks at the top there’s probably air bricks at the bottom and it’s maybe a cavity to to pull that through but it could be the roof I can’t I’ve Just Seen CH Jon say it’s a cavity wall Bungalow um so yeah I think James might be jumping on some answers there
Uh question around super full super quilt insulation um so our opinion on when using on a pitch roof in a loft conversion to help minimize loss of height does it affect breathability moisture in a bad way so this is a use of um super fall or super quilt if
You’ve come across them um as an insulation a on a pitched roof in a loft conversion y yeah yeah uh um it’s used a lot um it’s high performing um we don’t use it we we have removed it uh uh where we’ve kind of come across it um I
Haven’t looked at say it’s permeability uh to to to know to answer right now um kind of whether it’s appropriate to use with let’s say wood fi buildups and and other installations I have seen a couple of roofs which have had uh that sort of
Super foil put on the inside and then a wood fiber board placed on the inside of that but the foil blankets need a level of air around them I believe so they have to almost have that service void uh placed kind of with them as well to be
Able to work so whether then that’s a ventilated space or whether it’s just an unventilated um air gap within the buildup as well that will affect the performance too um I I kind of I think we like something more solid usually than the than the the sort of the
Blankets that can go on yeah I think the thing with those is they’re generally just um they’re not looking at insulation they’re more looking at reflection so reflecting of heat back down rather than the actual trapping um throughout sort of a low UV value of material with some thermal density and a low
Conductivity um so there’s slightly two different ways of managing heat retention um which can work I think as a general sort of um comment on any buildup that we’re using it’s all about trying to detail it correctly um and that’s to be honest even taking on um standard sort of
Manufacturing guidance and and buildups when you come to installing that in reality is paying very careful attention to where the air flow is where the G point is where the air type membrane is vapor control layer um and then how that integrates with how we used to build
Roofs um so making sure we still do have a um a secondary membrane if if needed under the TS because they never especially using old handmade clay double Romans they don’t sit perfectly flat so you will get you know excess moisture if you’re not careful um so one of our yeah
Constant sort of struggles is taking what’s been developed um with new materials and with higher levels of standards and detailing and for making that fit existing and it’s never never straightforward but that’s that’s probably regardless of what you use how you detail it is probably the biggest biggest difference um let’s see what
Else we got uh error gel uh has been mentioned briefly um we’ve never used it I don’t know if you’ve ever specified it I’ve seen it out quite a lot especially around uh reveals or Windows um I think it’s something we need to try but I don’t personally have any thoughts on it
Apart from the fact that inherently I’m a bit skeptical where it’s using traditional Mater sort building Fabrics just because of how it’s manufactured but yeah I’d need to have some time playing with it before I could comment on that um but I know it has been used
Um and and according to its um sort of stats data sheets it should be good just there we have had um some recommendations for it in conjunction with wood fiber insulation um by a lime green in Shropshire so they they produce wood fiber boards um and they do say particularly internal insulation if
You’re getting to those areas that could create some thermal Bridges but you just can’t fit in the appropriate thickness but it is better to put in something than nothing and a gel really good solution for that not a cheap solution um but yeah in those areas where you’re
Really really limited on space or potentially tucked down next to a staircase or something like that when you don’t move the stairs it can get you out of a a pickle it’s not ideal it’s not the optimal solution but it can potentially help yeah yeah we need to
Look into it um it’s come up in a few conversations but we just haven’t sort of played with because one of the hardest things about for us on the on the delivery side is having the space to play and to experiment um and this is where uh slightly different sort of
Conversation but it can get a bit frustrating when you see funding go towards um educational sort of Institutions but they’re not including the delivery Partners um so I saw some funding go towards bath recently and they need to be involving us on the ground not just us all the other
Companies so that we can get this joined up and double Loop feedback so we can actually play with these materials so we can confidently specify them for clients um there’s definitely a bit of a gap there between manufacturers developing new products specification installation and delivery and just that little space
In the Middle where you can just test and play um so hopefully we’ll have some more feedback on that in the future or other materials um let’s have a look done that future proofing on the roof structure for Solo in one of your slides what kind of work could that
Involve Ben um it it very much depends if the structure is up to taking the weight of the the the panel system essentially uh whether any additional sort of sheathing boards or things are needed lots of properties are just having solar panels put onto them onto
The existing uh roofs at the moment U but again with lots of old RS they’ve probably you know if they’re a 100 odd years old all the Timbers they probably moved a lot on in a pretty rigid solid place but it’s always worth getting an additional opinion from an engine ER on
The suitability of the sort of the Timber structure that’s in there as to whether it could take a x kilowatt um sort of solar system realistically um and it depends on what kind of system is is going on there you know we we’re talking with various clients uh at the
Moment about inline solar panels so not sort of penetrating or you know putting on an additional frame um they’re in sort of plastic uh um uh uh uh what would be called sort of in a plastic hous in almost so that reduces the weight a little bit that’s going onto
The roof but that’s on a new build other ones we replacing roof tiles with these sort of solar tiles and things now so if it’s a case of just getting a solar system put onto a roof there’s lots of different options around that as well that might lead into a retrofit or an
Upgrade a thermal upgrade of the roof as well as then potentially needing a structural Improvement as well I think it’s mainly the structural considerations in terms of if you have an opportunity to just get a calculation um and prepare the roof or improve the roof for future installation of solar
Panels then I think that’s mainly what sort of touched on there um most solar panels can be retrofitted appropriately you know when they come to do it and install it there’s no there’s nothing really you can do during the buildup um because they all designed to be installed on existing roofs it’s more
Probably just you making sure that the roof can take the load and adding anything whilst we have the opportunity you know adding any more Timbers or or any strength thing yeah potential for doubling up Timbers sistering them and those kinds of things so maybe not a
Whole new roof needed but it might be some additional uh in you know uh inserting some additional Timbers in to be able to support them uh question here from Christopher do your insulation principles work as well in Old timber frame buildings walls and roofs where Timbers are anything but uniform and
Parallel um I think firstly in terms of the performance of the materials yes absolutely a lot of natural materials um and you know any modern sort of natural materials work really well with additional buildups um in terms of where there anything but uniform parallel a lot of the fiber boards
Themselves come in smaller boards so they can follow the Contours of undulating roofs and ceilings a lot better um if we’re using this is in a roof context but in a all context uh material at hemp crat we generally go with a a lightweight timber frame where
We cast by hand into the void and that can fill any angulation of the Old Brick or or stone so so that can be very appropriate um for taking something that’s very yeah not very straight you know finishing with a straight straight face straight edge yes there are wood fiber boards as well
Which have a one one face of them um is slightly more malleable as well um I can’t remember the product but um again another project we’re working on where we’re looking at putting some external wool insulation on the C’s very keen on using wood fiber for that um um and
See having that that malleable kind of face to place against an undulating existing wall is is very very helpful to them be able to get a a nice smooth flush finish um externally brilliant and final question we got at the moment from Chris um can you use wool and straw for internal retrofitting
Ceilings um I wouldn’t we generally wouldn’t you can use straw and straw Bells but that generally would be part of quite either a large intervention or or re building a roof um so I’ve seen that used but you can’t leave it exposed you’ve got to finish the straw so when
We use um straw for our new build projects they are plasted internally and externally um what they are good when they’re dense enough in terms of fire EGS I think there’s just a lot and and also they’re not a like a tested product that you can buy off the shelf so I
Imagine there’ll be barriers to specifying that um I don’t know if in terms of Ed wall I mean it’s if it’s sheets wall and it’s a product then yes you could um I imagine you could just use wall that you have gathered yourself but again you it’s all about the performance certificates and
The testing and the um consistency um so it depends really I wouldn’t necess say go for straw um in that context uh I think that’s it from the question I think there there’s one more just uh just the last one that’s just sort of come in um so from from the
Admin on behalf of someone else uh we we’re hoping to upgrade our our flat roof is about a third of our roof space the rest is an apex roof with an insulated ceiling uh um if we and when we insulate the roof how do we fit over
The eaves we hope to insulate the walls in the future if we can not afford it yet we are aware of the loss of heat through the eaves if we do a warm roof currently roof felt with poor insulation between the rafters they can’t do anything from the
Inside so it’s all going to be built up from the outside so that uh sort of the eaves when insulate the eaves is very it’s an important Junction to essentially maintain sort of the thermal envelope so um being able to kind of pull the insulation all in line kind of
Down and around the property rather than having a bit of insulation here and a bit of insulation back on the walls or out on the walls and inside on the roof trying to maintain a line of insulation is is quite important in getting that sort of thermal envelope so again you’re
Mitigating against things like cold bridging um if you are looking or maybe don’t have the overhang that you need uh then things like sistering Timbers to create slightly deeper Eaves so they can come out over the external wool instulation when that is then done um we
Uh again it might be that you look to overboard the roof so whether you have to go through a planning application to raise the roof line raise the ridge potentially with uh with a a wood fiber sheathing board on the outside so that can marry up with the external wall
Insulation basically create a completely external kind of sheathing around the building I think it’s important to not there as well as you’re shifting insulation air out to the eaves and down that you’ve got to shift out the air ventilated space void because um you can see issues where people B insulate into
The eaves but they don’t allow for the air flow they there to go up and over um depending where you’ve got that detail whether it’s on the Apex or the flat imagine it’s more than the Apex um hard answer fully without pictures as always um I hope we cover some of that
There but George has left a nice link to uh a YouTube channel on flat Roofing um great I think that’s all of us isn’t it um oh I’ve got a nice noisy plane just going overhead um that was a really interesting point though I think
As well that came up um just then around thinking about your future plans not just what you’re dealing with right here and now um with a lot of the decisions that you’re making in retrofit um a lot of people aren’t doing everything in one go you’re you’re work either room by
Room or project by project as as the need arises um but it is really important to be thinking one two five steps ahead um of what you’re going to be doing next to make sure that you are getting everything lined up and one step is ready for the next and certainly not
Blocking the next um so yeah that is really interesting there and why is useful to get retrofit plans get retrofit advice um on your whole house really even if you are only starting on one part of it so you know um and even if it’s not for you if it’s if you’re
Planning on selling if it’s for future people that come along um you you’re doing things in the right order so excellent thank you ever so much Ben and David really good session again um had some great questions there as well which I hope you all enjoyed um in terms of
What’s coming up next we’ve got nothing Before Christmas um we do have how to retrofit the modern home in January and when I say modern that is um cavity wall construction so post 1920s 1930s um what you can do with that to reduce your energy consumption um and make it more
Carbon neutral um and we still have Future Ready homes is running till the end of January we do still have a tech panel available to answer questions so if you do have more detailed questions that have come up that haven’t been covered here here today or on something
Different please email me um with those and we can put them through through to our panel and get those responded and we put them on our website as well um which means that everyone can share in the in the learning and the information um so please do that uh yeah the recording
Will be with everyone in a couple of days so you can pick back up um there’s a lot of content in here so yeah you might want to watch again um and I’ll try and put some links into some of those resources that Ben mentioned
Towards the end as well the um yeah that we’ve got a couple of retrofit patn B Builders book that kind of thing so I’ll put some links in there as well um so all that leaves me to say is Happy Christmas hope you all have a lovely
Time um planning your retrofits and your roof insulations um that’s just what I do for my fun so it might just be me um yeah and we’ll see you in January hopefully