Actually the target for improvement of an existing thermal element is not 0.3, it's 0.7. 0.3 is for new builds or construction of new thermal elements.
Then, because of the risks of using non breathable materials on solid walls eg. PIR, the target of 0.7 can be challenged quite easily, since the Part L clearly gives a get out clause for buildings of traditional construction (eg. Solid walls). Then it moves from "meet this number" to "do the best you can, respecting the needs of the building fabric and payback".
Speak with your LABC, they will be happy any improvement is made, and 0.8 Vs 2.1 is a huge improvement which they will not ignore.
Source: I'm doing this via building notice and my LABC.
Also, I'm pretty sure the 25% improvement of a thermal element only triggers to need to aim for the target on the whole area of that thermal element eg. One wall.
if you are repairing render that is damaged, in order to prevent further damage to the fabric of the building, nobody can force you to add insulation.
New builds is 0.18: https://insulation4less.co.uk/blogs/guides-and-news/building-regs-u-values
Interesting that they are letting you do less though.
Edit: People downvoting really need to actually read the documents. It’s clearly 0.3 with anything over 0.7 (threshold) requires updating.
My mistake. But scroll down that page and you'll see the 0.7 for existing elements - internal insulation.
Just speak to them to discuss your project if you want to do it the 'right way', they are usually very understanding, and you can do it via building notice rather than submit full plans. Or just do it anyway.
Just follow the best practice for insulating solid walls, and use that with BC if you need to, they will not argue I'm sure.
Why do you care about building regs if you are making improvements that don't require inspection? It isn't like they condemn your house. Moreover, even if you were working under building control, for non saftey related issues it is usually same or better, not all the way to modern building regs.
You are absolutely right that 0.8 is loads better than 2.1. Like on a 0 degree day your house will lose 26W less per square meter of wall per hour. Even in a small corner room this adds up to 100s of Ws.
That’s how it should be, same or better. But with insulation it’s now: do this or nothing.
If you want to declare it for EPC or selling the house then you’d need a certificate no?
No, you don't need it to sell the house. Worst case for sales is you get an imdemnity policy (that would only pay out if the council required the new owner to fix something, which is incredibly unlikely , and so only cost like 50 quid). And this is only needed if the buyer wanted it.
> And this is only needed if the buyer wanted it.
Yeah... any mortgage company is going to require that at least even if the buyer isn't fussed. But as you say they're pretty cheap.
However, I wouldn't call that worst case. Worst case is that people refuse to buy it because fuck knows what standard you did the work to and an indemnity policy wouldn't cover poor workmanship. That said there'll always be a buyer, but it may require a significant price drop.
I don't disagree that your worst case is correct. That's the case with any improvement that doesn't have inspection by building control and specific sign-off though. Unlikely someone wouldn't want a new bathroom, but who checked that plumbing was done correctly? Obviously easier to put that right, but a leak would be a serious defect. The longer you own the house after doing and documenting the work the less likely anyone questions it when you do come to sell.
It's not really broken, because the LABC inspector will accept a reduced improvement under the discretionary clause based on practicality or cost, and in my experience they give a lot of leeway if you are a DIYer rather than a builder.
Are there people actually going around voluntarily telling the council that they're doing this work? Why? Just add what you want and keep your mouth shut.
You never used it obviously, but now you do for external walls. Again that’s what the regs say, which is obviously ridiculous. Which is my whole point.
We’re insulating our house. We’re using internal wood fibre boards in one room. In another we’re using insulated plaster…it’s all down to how much room we’re prepared to lose.
I’m not telling anyone. It’s just for us to save on energy
I've told them for mine, but mainly because I want them on my side when I do some electrics later 😂
Which woodfibre and plaster materials are you using?
I'll second Chris at Back to Earth as a merchant. Great advice, sensible pricing, good service re follow-on questions
Source: about 400mm thick wood fibre insulation all over the roof, 200mm externally on two walls, 100mm internally on one wall. Rear extension with 300mm sheep's wool in floors and walls so no wood fibre there...
Why internal not external insulation? I know it isn't suitable for a lot of people for a lot of reasons but if you can, you won't lose room space and your house will be far more thermally stable with the mass of the walls inside the thermal envelope.
I had building regs guy round the other day to sign some structural work off, he asked if im insulating the walls, i said i might use insulated plasterboard, he said good idea, he did not care about if i was and wasn't and he didn't say if i was it needed to be signed off, if your insulating a old cold house your making it better then it was
Ive of course insulated plasterboard the rooms ive already done but didnt want to mention it as im aware of the u valve that needs to be met just in case
There are different types of insulated plasterboards out there, i have solid stone walls and used pir 37.5 insulated plasterboard on all external walls and the rooms are like ovens, the 100mm stuff is the cheaper stuff with worse u valve, the better stuff has better u valve at less thickness
Honestly, I think these rules are completely nuts. It's completely unaffordable to insulate a solid wall house according to building regs as far as I can see. Payback time is 6-9 years at least, and even if you go ahead and do it, if you have any problems with rising damp, structural issues, or condensation following the installation it's going to be a whole world of trouble. So yeah, I think you are right, sadly... but interested in what others think
Yeah I’ve been looking into it for a while and nothing makes sense.
You can add insulation relativity cheaply and get significant improvements, why stop that when the goal is to insulate more properties!
10 years is good. What's the payback time on a new kitchen? Realistically the UK has incredibly thermally inefficient houses compared to our neighbours. I guess the trade off is how many more people will do the insulation to a good U Value if mandated, versus those who are put off insulating to a slightly better U value because of these rules?
Think how many extensions and renovations are currently being built that have good thermal properties because of these regs, versus the number of Barrys who are put off from installing rockwool between the floor joists on their Saturday.
Realistically though, I'd just do it. Does replacing plasterboard even count as a renovation? It's something you'd do for cosmetic/maintenance reasons if the walls were knackered
I've dropped my house's wall U value from ~2.05 (brick, 1" air gap, brick, 1" of bonding and finish plaster) to 0.39 by removing the plaster, adding 50mm PIR to the walls, overboarding with plasterboard and jointing & taping or skimming it.
Am I telling building control? Absolutely not. Am I storing receipts and photos for when I eventually get an EPC done? You betcha.
Granted it's trickier with solid walls given the issues around moisture management, but you absolutely should shoot for 0.8 and enjoy losing 40% of the heat you were previously. You also absolutely don't need to tell BC, but if you do, I think you'll find that every element of the building you work on must be "no worse than it was before", and they'll be happy you are doing even the smallest amount of insulating.
Anyone managed to get financial support for this? I've got a freezing north-facing common-brick cavity-wall outrigger but we're too close to the sea to fill the cavity. It desperately needs internal or external insulation but at 7mtrs long and high ceilings, radiators and kitchen units inside, guttering, soil pipes doors and windows outside, it's a major job either way. We earn just over £35k, and I've not heard of any support outside of cavity fill under the current scheme, which just isn't suitable afaik.
Try your local authority. But probably not.... You mean over £35k each or combined household income? If so you are in receipt of universal credit?
There is also GBIS, Google it. But they don't like certain buildings
I don't think I'd get anything from the DWP with our income just above £35k.
I've gone through the Q&A from Octopus for the GBIS and don't get a great feeling about it. I've already topped up the attic myself a few years ago and there's no mention of external or internal insulation so far, just cavity which both the neighbours got years ago for free and I don't think it went well for them.
From what I've read about current heat pump grants, homeowners have to organise and pay for the insulation themselves if its needed. But I could be wrong.
As a DEA/RA I hate GBIS, I thought it was going to make things much more accessible for everyone. Nope, turns out it is shit for the customer and shit for the supplier.
We can only install one measure (not totally accurate, we can install certain heating controls at the same time).
Still heavily skewed towards home owners rather than everyone, a total shit show not fit for purpose!
I would rather have it so it is fairer to everyone.
It is much easier to get things through if the customer is a home owner and I don't believe that is fair or right.
Everyone should have the same access to the grants that are available.
We were able to get the cavity filled with a non-moisture retentive fibreglass wool type stuff and the loft topped up to 300mm with mineral wool totally for free on a council grant. We are in the North West on a hill so driving rain is a factor but everything has stayed completely dry and toasty warm so far. As part of the install they will survey your ventilation and add extractor fans or PIV loft systems to ensure there's no build up of damp due to the changes.
No income requirement for us, just had to have an EPC of C or below and council tax band of D or above.
You can also get breathable paints and creams that go on your bricks that prevent driving rain moisture ingress but allow the bricks to breathe. Additionally the blown EPS insulation beads into a cavity are supposed to naturally let water flow to the ground rather than bridging the cavity. The only reason they weren't recommended for us is because they can deteriorate cables that have been run in the cavity without conduit apparently.
Interesting. Where are you? The household income cut-off for support afaik in Lancs is £35k. I'm about 100mtrs from the sea, so the humidity levels are very high. You can get condensation on the street where it looks like it's been raining. We're band A with the council, the EPC is out of date but I'd imagine we're a D or E. PIV would be ideal here I think for positive pressure because there's always a gale blowing.
The state pumped Billions into big oil through the Ukraine invasion - more than it'll ever spend decarbonising British homes. I've never claimed a penny.
The second property has fa equity in it. My main home is worth £130k. Both are mortgaged and hit by rising rates. Fully decarbonising it would cost a quarter of its value. I'm not sitting pretty in the South Downs. If you have an axe to grind, go take it out on the people who swanned around in £50k EV's without being charged VAT back in the day. I'm not interested. Decarbonising my home is beyond me either way. Landlord or not. If I can get some support from the state to do it, then when they have to bail out big oil again in the next 5 years, it'll cost them less and you can thank me then.
Have a look at Calcium Silicate insulation. It's the best insulation you can buy but it is expensive.
[https://www.ecologicalbuildingsystems.com/shop-by-brand/calsitherm](https://www.ecologicalbuildingsystems.com/shop-by-brand/calsitherm)
[https://www.ecomerchant.co.uk/skamowall-board-1-000mm-x-600mm-x-25mm-or-50mm.html](https://www.ecomerchant.co.uk/skamowall-board-1-000mm-x-600mm-x-25mm-or-50mm.html)
Any insulation will slow heat loss and make your heating more effective. Lining internally may also reduce air gaps and leakage meaning less heat loss as well.
Equivalent of an open window would negate those gains my puny brain thinks.
Picture a perfectly insulated house. Leave a window open. All that green energy warmed air goes outside. Has anyone shown an actual lowered btu usage when not plugging the vents?
I’m back living in uk after leaving as a kid so I’m not completely familiar with vent bricks etc. all I know is that my 1940s brick house in Whitby is vented in and out totalling about an open widow of free air flow.
If you’re want to minimise lost space and meet the building regulations, strip the plaster off to the masonry and line with an insulated plasterboard. Kingspan Kooltherm K118 has the best performance.
It's not always suitable as you then have to render the house which can be a great cost if you only want/need to insulate one or two walls, and can move it out of keeping with other houses and likely requires planning permission. Our estate is all sandstone effect brick exteriors in keeping with the older properties in the vicinity. I don't think we'd be allowed to render it at all.
What work are you doing that means you need to meet regs? Unless it’s a change of use you don’t need to do anything to a residential property and it’s up to you how you insulate it, if at all. The aim is to slowly improve buildings over time so if you don’t meet the criteria as long as it’s ’no worse than existing’ then it’s fine.
I've had a right trauma recently with this. 1m section of exterior wall, previously timber stud with wooden door. Rotted.
50mm cavity.
Managed to oversail to give myself 75mm cavity. But:
*any full fill insulation, such as dritherm 32 75mm, is impossible to source unless you're buying an entire pallet. This just barely gets you to .30
*pir usually rated for 40mm airgap or more. Anything rated for a 10mm gap, i.e. kolltherm 106, only comes in sizes 90mm plus.
We're rapidly approaching the point where you simply can't meet regs without insulated plasterboard eating into the room. Which is actually pointless unless you're doing the entire thermal envelope.
Edit: basically building control kept changing their mind about whether it was renovation or a new thermal element.
You need to calculate how much of the room you're gonna lose insulating internally. If it's over 5% (from memory), and you can't insulate the cavity, then the less stringent targets apply
I have a double brick no cavity Victorian.
I striped the exterior paint, removed interior wallpaper and plaster, added 2x4 treated wood interior wall with rock wool and fit thermal bridging used the hard rock the brand makes. Then vapour barrier as per regs (personally I think it is meh) plasterboard with sound board and breathable paint.
The quality of life, with sound improvement and warmth and to not feel drafts is the cherry on the top of paying 1/5 of others pay in houses like ours. The 10cm did not even register behind curtains and wardrobes. If anything the window reveals look nicer and more sturdy.
For smaller rooms as someone suggested go less ambitious with the insu depth.
Don't use PIR. They are the worst for breathability and fire and fitting correctly takes a huge amount of expensive foam.
TLDR
It is not just about the bill being cut down and environmentally responsibility, but also the quality of life is improvement immensely.
Actually the target for improvement of an existing thermal element is not 0.3, it's 0.7. 0.3 is for new builds or construction of new thermal elements. Then, because of the risks of using non breathable materials on solid walls eg. PIR, the target of 0.7 can be challenged quite easily, since the Part L clearly gives a get out clause for buildings of traditional construction (eg. Solid walls). Then it moves from "meet this number" to "do the best you can, respecting the needs of the building fabric and payback". Speak with your LABC, they will be happy any improvement is made, and 0.8 Vs 2.1 is a huge improvement which they will not ignore. Source: I'm doing this via building notice and my LABC.
Also, I'm pretty sure the 25% improvement of a thermal element only triggers to need to aim for the target on the whole area of that thermal element eg. One wall. if you are repairing render that is damaged, in order to prevent further damage to the fabric of the building, nobody can force you to add insulation.
And if payback is more than 10 years you don't need to do it, just what you can with a quicker payback.
New builds is 0.18: https://insulation4less.co.uk/blogs/guides-and-news/building-regs-u-values Interesting that they are letting you do less though. Edit: People downvoting really need to actually read the documents. It’s clearly 0.3 with anything over 0.7 (threshold) requires updating.
My mistake. But scroll down that page and you'll see the 0.7 for existing elements - internal insulation. Just speak to them to discuss your project if you want to do it the 'right way', they are usually very understanding, and you can do it via building notice rather than submit full plans. Or just do it anyway. Just follow the best practice for insulating solid walls, and use that with BC if you need to, they will not argue I'm sure.
That’s the threshold (anything higher has to be reduced) the improvement is still 0.3 on that table.
Why do you care about building regs if you are making improvements that don't require inspection? It isn't like they condemn your house. Moreover, even if you were working under building control, for non saftey related issues it is usually same or better, not all the way to modern building regs. You are absolutely right that 0.8 is loads better than 2.1. Like on a 0 degree day your house will lose 26W less per square meter of wall per hour. Even in a small corner room this adds up to 100s of Ws.
That’s how it should be, same or better. But with insulation it’s now: do this or nothing. If you want to declare it for EPC or selling the house then you’d need a certificate no?
If u have pictures and details of what u do Epc chap will add it to his report and grade it accordingly
That’s good to know at least!
You can see your current EPC and what it will add.
I've found EPC outcome to be largely based on how much the surveyor knows about the system or cares.
No, you don't need it to sell the house. Worst case for sales is you get an imdemnity policy (that would only pay out if the council required the new owner to fix something, which is incredibly unlikely , and so only cost like 50 quid). And this is only needed if the buyer wanted it.
> And this is only needed if the buyer wanted it. Yeah... any mortgage company is going to require that at least even if the buyer isn't fussed. But as you say they're pretty cheap. However, I wouldn't call that worst case. Worst case is that people refuse to buy it because fuck knows what standard you did the work to and an indemnity policy wouldn't cover poor workmanship. That said there'll always be a buyer, but it may require a significant price drop.
I don't disagree that your worst case is correct. That's the case with any improvement that doesn't have inspection by building control and specific sign-off though. Unlikely someone wouldn't want a new bathroom, but who checked that plumbing was done correctly? Obviously easier to put that right, but a leak would be a serious defect. The longer you own the house after doing and documenting the work the less likely anyone questions it when you do come to sell.
Yeah true, but that just further highlights how pointless and broken it is.
It's not really broken, because the LABC inspector will accept a reduced improvement under the discretionary clause based on practicality or cost, and in my experience they give a lot of leeway if you are a DIYer rather than a builder.
Are there people actually going around voluntarily telling the council that they're doing this work? Why? Just add what you want and keep your mouth shut.
That’s not really the point, it’s the principle of it that’s frustrating. If they were logical and reasonable why not get approval.
No OP it is the point
...... who the fuck is informing their council they intend to replaster a wall.
You never used it obviously, but now you do for external walls. Again that’s what the regs say, which is obviously ridiculous. Which is my whole point.
And then have to get a few indemnity policies when you sell and can't produce the certs. Or worse have people withdraw from the sale over it.
Ahhh, you'll be paying for those anyway if your house isnt a new build.
We’re insulating our house. We’re using internal wood fibre boards in one room. In another we’re using insulated plaster…it’s all down to how much room we’re prepared to lose. I’m not telling anyone. It’s just for us to save on energy
I've told them for mine, but mainly because I want them on my side when I do some electrics later 😂 Which woodfibre and plaster materials are you using?
Proof shield render for one room. Back to earth are supplying thermal boards. They can provide specs that’ll work for you
I'll second Chris at Back to Earth as a merchant. Great advice, sensible pricing, good service re follow-on questions Source: about 400mm thick wood fibre insulation all over the roof, 200mm externally on two walls, 100mm internally on one wall. Rear extension with 300mm sheep's wool in floors and walls so no wood fibre there...
Like a lot of rules, for home use they can be ignored.
Have a read of page 26 of approved document L volume1. You'll see it says to just try your best. So dont worry about it, just add as much as you can.
Why internal not external insulation? I know it isn't suitable for a lot of people for a lot of reasons but if you can, you won't lose room space and your house will be far more thermally stable with the mass of the walls inside the thermal envelope.
You also avoid having to deal with thermal bridging at floors/ceilings.
I had building regs guy round the other day to sign some structural work off, he asked if im insulating the walls, i said i might use insulated plasterboard, he said good idea, he did not care about if i was and wasn't and he didn't say if i was it needed to be signed off, if your insulating a old cold house your making it better then it was Ive of course insulated plasterboard the rooms ive already done but didnt want to mention it as im aware of the u valve that needs to be met just in case There are different types of insulated plasterboards out there, i have solid stone walls and used pir 37.5 insulated plasterboard on all external walls and the rooms are like ovens, the 100mm stuff is the cheaper stuff with worse u valve, the better stuff has better u valve at less thickness
Honestly, I think these rules are completely nuts. It's completely unaffordable to insulate a solid wall house according to building regs as far as I can see. Payback time is 6-9 years at least, and even if you go ahead and do it, if you have any problems with rising damp, structural issues, or condensation following the installation it's going to be a whole world of trouble. So yeah, I think you are right, sadly... but interested in what others think
Below 10 years is amazing!
Yeah I’ve been looking into it for a while and nothing makes sense. You can add insulation relativity cheaply and get significant improvements, why stop that when the goal is to insulate more properties!
10 years is good. What's the payback time on a new kitchen? Realistically the UK has incredibly thermally inefficient houses compared to our neighbours. I guess the trade off is how many more people will do the insulation to a good U Value if mandated, versus those who are put off insulating to a slightly better U value because of these rules? Think how many extensions and renovations are currently being built that have good thermal properties because of these regs, versus the number of Barrys who are put off from installing rockwool between the floor joists on their Saturday. Realistically though, I'd just do it. Does replacing plasterboard even count as a renovation? It's something you'd do for cosmetic/maintenance reasons if the walls were knackered
I've dropped my house's wall U value from ~2.05 (brick, 1" air gap, brick, 1" of bonding and finish plaster) to 0.39 by removing the plaster, adding 50mm PIR to the walls, overboarding with plasterboard and jointing & taping or skimming it. Am I telling building control? Absolutely not. Am I storing receipts and photos for when I eventually get an EPC done? You betcha. Granted it's trickier with solid walls given the issues around moisture management, but you absolutely should shoot for 0.8 and enjoy losing 40% of the heat you were previously. You also absolutely don't need to tell BC, but if you do, I think you'll find that every element of the building you work on must be "no worse than it was before", and they'll be happy you are doing even the smallest amount of insulating.
Anyone managed to get financial support for this? I've got a freezing north-facing common-brick cavity-wall outrigger but we're too close to the sea to fill the cavity. It desperately needs internal or external insulation but at 7mtrs long and high ceilings, radiators and kitchen units inside, guttering, soil pipes doors and windows outside, it's a major job either way. We earn just over £35k, and I've not heard of any support outside of cavity fill under the current scheme, which just isn't suitable afaik.
Try your local authority. But probably not.... You mean over £35k each or combined household income? If so you are in receipt of universal credit? There is also GBIS, Google it. But they don't like certain buildings
£35k all in. No UC. Thanks. I'm on a waiting list for GBIS through Octopus, but I'm not that optimistic. Looks pretty basic.
Why are you not claiming UC? What looks basic?
I don't think I'd get anything from the DWP with our income just above £35k. I've gone through the Q&A from Octopus for the GBIS and don't get a great feeling about it. I've already topped up the attic myself a few years ago and there's no mention of external or internal insulation so far, just cavity which both the neighbours got years ago for free and I don't think it went well for them. From what I've read about current heat pump grants, homeowners have to organise and pay for the insulation themselves if its needed. But I could be wrong.
GBIS is a different scheme. You both working full time?
No. I work ft more or less at 48 weeks pa. Mum's a sole trader working around the school schedule from home. 1 child.
You have a child? Yes make a claim for UC. As long as you don't have £16k in savings you should get help
I should have mentioned that I own a small second property, mostly mortgaged, which usually rules us out. But thank you.
There we go lol. Yes nothing in that case.
heat pump installs no longer require the homeowner to purchase additional insulation for the grant as of this month.
Useful info thanks. 'bout time. At the rate it's going it was looking like it was just going to be another failed scheme.
It’ll be next to useless if your home is not insulated.
And if you’re already fully insulated but the stipulation is *buy more*?
As a DEA/RA I hate GBIS, I thought it was going to make things much more accessible for everyone. Nope, turns out it is shit for the customer and shit for the supplier. We can only install one measure (not totally accurate, we can install certain heating controls at the same time). Still heavily skewed towards home owners rather than everyone, a total shit show not fit for purpose!
So you rather home owners didn't have it? Sorry I don't know too much about the schemes but isn't it done by energy companies?
I would rather have it so it is fairer to everyone. It is much easier to get things through if the customer is a home owner and I don't believe that is fair or right. Everyone should have the same access to the grants that are available.
We were able to get the cavity filled with a non-moisture retentive fibreglass wool type stuff and the loft topped up to 300mm with mineral wool totally for free on a council grant. We are in the North West on a hill so driving rain is a factor but everything has stayed completely dry and toasty warm so far. As part of the install they will survey your ventilation and add extractor fans or PIV loft systems to ensure there's no build up of damp due to the changes. No income requirement for us, just had to have an EPC of C or below and council tax band of D or above. You can also get breathable paints and creams that go on your bricks that prevent driving rain moisture ingress but allow the bricks to breathe. Additionally the blown EPS insulation beads into a cavity are supposed to naturally let water flow to the ground rather than bridging the cavity. The only reason they weren't recommended for us is because they can deteriorate cables that have been run in the cavity without conduit apparently.
Interesting. Where are you? The household income cut-off for support afaik in Lancs is £35k. I'm about 100mtrs from the sea, so the humidity levels are very high. You can get condensation on the street where it looks like it's been raining. We're band A with the council, the EPC is out of date but I'd imagine we're a D or E. PIV would be ideal here I think for positive pressure because there's always a gale blowing.
You’re a a landlord. Sell up and improve your families living conditions rather than trying to drain the state of cash.
The state pumped Billions into big oil through the Ukraine invasion - more than it'll ever spend decarbonising British homes. I've never claimed a penny.
What has that got to with anything?! You’re queuing for a grant for insulation when you own a second property.
The second property has fa equity in it. My main home is worth £130k. Both are mortgaged and hit by rising rates. Fully decarbonising it would cost a quarter of its value. I'm not sitting pretty in the South Downs. If you have an axe to grind, go take it out on the people who swanned around in £50k EV's without being charged VAT back in the day. I'm not interested. Decarbonising my home is beyond me either way. Landlord or not. If I can get some support from the state to do it, then when they have to bail out big oil again in the next 5 years, it'll cost them less and you can thank me then.
Who would know? If you plaster a wall or add 50mm insulation to your old walls instead of 100mm who will know?
Have a look at Calcium Silicate insulation. It's the best insulation you can buy but it is expensive. [https://www.ecologicalbuildingsystems.com/shop-by-brand/calsitherm](https://www.ecologicalbuildingsystems.com/shop-by-brand/calsitherm) [https://www.ecomerchant.co.uk/skamowall-board-1-000mm-x-600mm-x-25mm-or-50mm.html](https://www.ecomerchant.co.uk/skamowall-board-1-000mm-x-600mm-x-25mm-or-50mm.html)
Fuck the regs. A little insulation is better than none.
Is it? What’s the point of any insulation when brick buildings have the equivalent of a continuously open window via the various vents?
Any insulation will slow heat loss and make your heating more effective. Lining internally may also reduce air gaps and leakage meaning less heat loss as well.
Equivalent of an open window would negate those gains my puny brain thinks. Picture a perfectly insulated house. Leave a window open. All that green energy warmed air goes outside. Has anyone shown an actual lowered btu usage when not plugging the vents? I’m back living in uk after leaving as a kid so I’m not completely familiar with vent bricks etc. all I know is that my 1940s brick house in Whitby is vented in and out totalling about an open widow of free air flow.
Some people need to stop shitting their pants over the building inspection fairies and just get on with stuff.
If you’re want to minimise lost space and meet the building regulations, strip the plaster off to the masonry and line with an insulated plasterboard. Kingspan Kooltherm K118 has the best performance.
Need to use breathable materials with old buildings
That's a myth. If you use a vapour control membrane you can use any material.
If you want everything to rot then yes go ahead.
Do you have the space to externally insulate the walls?
It's not always suitable as you then have to render the house which can be a great cost if you only want/need to insulate one or two walls, and can move it out of keeping with other houses and likely requires planning permission. Our estate is all sandstone effect brick exteriors in keeping with the older properties in the vicinity. I don't think we'd be allowed to render it at all.
You also need the eaves to be big enough for the insulation + render to still sit under them by a certain amount.
What work are you doing that means you need to meet regs? Unless it’s a change of use you don’t need to do anything to a residential property and it’s up to you how you insulate it, if at all. The aim is to slowly improve buildings over time so if you don’t meet the criteria as long as it’s ’no worse than existing’ then it’s fine.
I've had a right trauma recently with this. 1m section of exterior wall, previously timber stud with wooden door. Rotted. 50mm cavity. Managed to oversail to give myself 75mm cavity. But: *any full fill insulation, such as dritherm 32 75mm, is impossible to source unless you're buying an entire pallet. This just barely gets you to .30 *pir usually rated for 40mm airgap or more. Anything rated for a 10mm gap, i.e. kolltherm 106, only comes in sizes 90mm plus. We're rapidly approaching the point where you simply can't meet regs without insulated plasterboard eating into the room. Which is actually pointless unless you're doing the entire thermal envelope. Edit: basically building control kept changing their mind about whether it was renovation or a new thermal element.
How was it resolved?
I stopped giving a fuck. Bunged some thermawall 50mm in. If anybody asks, it is a 100mm cavity now.
Yeah that’s the point in getting too!
You need to calculate how much of the room you're gonna lose insulating internally. If it's over 5% (from memory), and you can't insulate the cavity, then the less stringent targets apply
Don’t need building control for repairs. You are over thinking this
On external walls you do now if you repair over 25%. Came in last year.
Why are you getting building regs involved? Just do it and don't mention it.
I have a double brick no cavity Victorian. I striped the exterior paint, removed interior wallpaper and plaster, added 2x4 treated wood interior wall with rock wool and fit thermal bridging used the hard rock the brand makes. Then vapour barrier as per regs (personally I think it is meh) plasterboard with sound board and breathable paint. The quality of life, with sound improvement and warmth and to not feel drafts is the cherry on the top of paying 1/5 of others pay in houses like ours. The 10cm did not even register behind curtains and wardrobes. If anything the window reveals look nicer and more sturdy. For smaller rooms as someone suggested go less ambitious with the insu depth. Don't use PIR. They are the worst for breathability and fire and fitting correctly takes a huge amount of expensive foam. TLDR It is not just about the bill being cut down and environmentally responsibility, but also the quality of life is improvement immensely.