crispy_wafer Posted February 16 Posted February 16 (edited) You’ve got ventilation going on above the roof insulation which is good, however the detailing of the pir install is not so good, which may well be allowing this ventilation a path down behind the plasterboard. For me, the gaps need filling then taping over before any hint of the ceiling plasterboard goes up. Because there are gaps the cold outside air is making its way round the plasterboarded wall. Tiles off or ceiling down. Fill the gaps, tape up jobs a goodun. Save it for the summer though A common method for fixing the plasterboard not having continuous ribbon of adhesive round the perimeter of each board is to drill a series of holes at specific intervals and squirt a low expansion foam (Illbruck or soudal) what have you got on the ceiling? Is it insulated board or just regular board? needs rectifying really, don’t want to say you’ll end up with mould issues but it’s possible where the colder spots are. Edited February 16 by crispy_wafer 1
EinTopaz Posted February 16 Author Posted February 16 22 minutes ago, Onoff said: You could hide it with coving..... Could do, would my suggestion of cutting the top 5cm off the board and sealing the bottom of the angled plasterboards work then? No one confirmed if my idea was silly or not. 20 minutes ago, Onoff said: After this point, I'm assuming aside from not foaming the gaps, that they didn't then foil tape over the timber joists so that and the foil on the PIR became an airtight membrane? I've not seen any evidence that they've used tape over the timber joists, but there is a another layer of 50mm kingspan below the joists. Not sure if there's an airgap between joist and 50mm kingspan however. 20 minutes ago, Onoff said: Did they use cavity closers around the windows? Based on these two images, i'd say so. yes
EinTopaz Posted February 16 Author Posted February 16 19 minutes ago, crispy_wafer said: You’ve got ventilation going on above the roof insulation which is good, however the detailing of the pir install is not so good, which may well be allowing this ventilation a path down behind the plasterboard. For me, the gaps need filling then taping over before any hint of the ceiling plasterboard goes up. Because there are gaps the cold outside air is making its way round the plasterboarded wall. Tiles off or ceiling down. Fill the gaps, tape up jobs a goodun. Save it for the summer though I agree based on the image where the roof kingspan installation is visible. I think ceiling down will be traumatic, as it has 50mm kingspan below the joists so to get to that 100mm between joists layer, id have to remove all the 50mm kingspan too. So thinking perhaps best to go from above? Tiles and membrane off? 20 minutes ago, crispy_wafer said: A common method for fixing the plasterboard not having continuous ribbon of adhesive round the perimeter of each board is to drill a series of holes at specific intervals and squirt a low expansion foam (Illbruck or soudal) I was reading about this, it sounds fiddly and hard to tell whether you've squirted enough in to fix the problem? or too much and the wall starts bloating? plus how would one know if you've put foam over one of the places where the dabs are. Is it not easier just to try and add the continuous ribbon of adhesive by cutting some of the top of the plasterboards away and sealing, then re adding the plasterboard for that portion? 22 minutes ago, crispy_wafer said: what have you got on the ceiling? Is it insulated board or just regular board? needs rectifying really, don’t want to say you’ll end up with mould issues but it’s possible where the colder spots are. It's 100mm kingspan between joists, 50mm under joists, normal plasterboard.
MikeGrahamT21 Posted February 16 Posted February 16 3 hours ago, EinTopaz said: Ok that's good, saw the price of replacement soffits and assume they're all nailed in and can't remove without damaging. So if it's possible to do with tiles that will save me some faff. I guess I only need to inspect a meter wide to see evidence, if confirmed I can take some more off and continue to fix. Time consuming but i dont mind if it will lead to an improvement. Forgive my naivety but parge coating as in a full sealing pass of the block before the plasterboard goes on? I assume it's too late for me now unless I remove all the plasterboard. likewise for wet plastering, as in no plasterboard and plaster directly the blocks? Yeah it’s something which would need to be done before boarding out, and if your going to the effort of taking the boards off, for me I’d just wet plaster, but I would imagine it’s just not financially viable. I too have one room with dot and dab from when I didn’t know any different, I’ve tried my best to improve it but it’s still far from airtight, again not much I can do now without a lot of time and effort 1
EinTopaz Posted February 16 Author Posted February 16 (edited) 1 hour ago, MikeGrahamT21 said: Yeah it’s something which would need to be done before boarding out, and if your going to the effort of taking the boards off, for me I’d just wet plaster, but I would imagine it’s just not financially viable. I too have one room with dot and dab from when I didn’t know any different, I’ve tried my best to improve it but it’s still far from airtight, again not much I can do now without a lot of time and effort What about the option of adding more internal insulation over the top? I know it won't fix the cold behind the plasterboard I have. But maybe it'll help with comfort levels for the room? i.e If I hard fix some insulated plasterboard to the already plasterboarded walls and ceiling? Or perhaps add studs to them with insulation inbetween and then plasterboard over the top. Do you think that will make much difference? Edited February 16 by EinTopaz
Onoff Posted February 16 Posted February 16 Would adding Putty Pads to the sockets help cut down the air leakage through them? https://passivefireprotection.co.uk/socket-box-protection---ceukca-126-c.asp 1
EinTopaz Posted February 16 Author Posted February 16 5 minutes ago, Onoff said: Would adding Putty Pads to the sockets help cut down the air leakage through them? https://passivefireprotection.co.uk/socket-box-protection---ceukca-126-c.asp I've stopped the draughts but putting rockwool around the sockets, well the space around them. For all future ones i'll be using the putty for sure. Though the concern is not just the draughts, it's that there's loads of air behind the plasterboard and making it real cold. I need to fix it at the source really. Rather than at the end of the air chain, if that makes sense!
Onoff Posted February 16 Posted February 16 @SteamyTea was it you who mentioned the term I think "wind washing"? On the lines that cold air blowing around the cavity i.e the other side of the plasterboard just strips it of heat?
SteamyTea Posted February 17 Posted February 17 6 hours ago, Onoff said: @SteamyTea was it you who mentioned the term I think "wind washing"? On the lines that cold air blowing around the cavity i.e the other side of the plasterboard just strips it of heat? I have mentioned it before, not my term, but happy to take credit for it.
EinTopaz Posted February 17 Author Posted February 17 Had an air test done today, they have found a few more places of leakage which i'm on with sorting now. Worst offender was somewhere I wouldn't have even thought to look - Around the top and sides of the door architrave. Also pointed out a few places round the edges of the windows was quite bad, and weirdly beneath the coir matting near the french rear doors. So i'll be lifting that and having a look under there, I suspect that one particularly is where the skirting board isn't sealed properly.
EinTopaz Posted February 17 Author Posted February 17 Also, lifted up a couple tiles on the bottom row of the pitched roof. Just to see what I could find. Was quite hard to see but put my camera in there, but I assume what i'm looking at there is the 100mm wall kingspan, up against the block and wallplate. with what looks like some rockwool over the top. Should the kingspan be up tight against the block there? it looks like there may be a bit of a gap. If I can't budge it, should I get that foam filled or stuff some wool down there etc? If there's a gap that's essentially bypassing all the wall insulation like that?
EinTopaz Posted February 18 Author Posted February 18 21 hours ago, EinTopaz said: Also, lifted up a couple tiles on the bottom row of the pitched roof. Just to see what I could find. Was quite hard to see but put my camera in there, but I assume what i'm looking at there is the 100mm wall kingspan, up against the block and wallplate. with what looks like some rockwool over the top. Should the kingspan be up tight against the block there? it looks like there may be a bit of a gap. If I can't budge it, should I get that foam filled or stuff some wool down there etc? If there's a gap that's essentially bypassing all the wall insulation like that? Also the piece above the wooden wall plate there, Am I correct to assume that would be the upper layer of the roof kingspan? as in the 100mm layer that's between the roof joists? I drew a little cross-section here to help get my head around it. Is this correct?
Mr Punter Posted February 18 Posted February 18 22 minutes ago, EinTopaz said: Also the piece above the wooden wall plate there, Am I correct to assume that would be the upper layer of the roof kingspan? as in the 100mm layer that's between the roof joists? I drew a little cross-section here to help get my head around it. Is this correct? That is quite often a weak point. It sometimes gets filled with mineral wool but there is a risk that too much can be added, closing off airflow beneath the roof tiles. I think your issues are mostly be reveals, external thresholds and dot and dabbed plasterboard. If you drill small holes every 200mm around the top of the walls you could squirt in some expanding foam. Along the bottom, remove the skirting board, foam the gap and replace.
EinTopaz Posted February 18 Author Posted February 18 10 hours ago, Mr Punter said: That is quite often a weak point. It sometimes gets filled with mineral wool but there is a risk that too much can be added, closing off airflow beneath the roof tiles. I think your issues are mostly be reveals, external thresholds and dot and dabbed plasterboard. If you drill small holes every 200mm around the top of the walls you could squirt in some expanding foam. Along the bottom, remove the skirting board, foam the gap and replace. I think you're right. I'd like to remove the first 3 rows of tiles from the eaves upwards and fix from outside, If I get decent access from above im hoping to be able to access and seal both; any gaps between wall insulation and block at the top. And any gaps between wall plate and roof insulation. If that doesn't fix it, id be tempted to take all tiles off and foam / tape all the gaps in the insulation between the roof rafters. The suggestion of 200mm holes and foaming scares me a bit after reading about the walls bulging and looking pregnant etc. Could I not instead just cut off the top 5-10cm of the plasterboarded walls and run a solid big long bead of adhesive all across the wall, then refit new plasterboard to that? Or is that silly? Im just thinking atleast then im not doing anything blind, as it were.
G and J Posted February 19 Posted February 19 Making good will be a lot easier with the regular small holes/ injection idea. You could try it in one area, and if it works without bloating the plasterboard then fab, if not you’ve only a small area to redo. As an aside, I now realise why our early drawings specified a bead of silicone at the bottom of all skirtings. 1
Super_Paulie Posted February 19 Posted February 19 (edited) Id be tempted to remove a few rows of tiles to check it out from above. It's a shame they didn't do the insulation as good as they should as it looks a decent job otherwise. This is why I have trust issues with trades... I did ask my own insulation and foamed and taped absolutely everything as belt and braces, my roof level PIR is angled to meet the insulation in the cavity which I think you may be missing? Id get some of those tiles off to check it out as my place is never cold even though it's a 1930s. Edited February 19 by Super_Paulie 2
crispy_wafer Posted February 19 Posted February 19 I’d give the top of the plasterboard a knock with the side of your hand or a fist , you should be able to hear/feel where there is adhesive, sounds are different to where there is none. 1
EinTopaz Posted February 19 Author Posted February 19 6 hours ago, G and J said: Making good will be a lot easier with the regular small holes/ injection idea. You could try it in one area, and if it works without bloating the plasterboard then fab, if not you’ve only a small area to redo. As an aside, I now realise why our early drawings specified a bead of silicone at the bottom of all skirtings. I see your logic yeah. I'm just uncomfy with the fact that I can't see what it's doing on the other side to be honest. Not just because of the bulging, but also because I can't confirm that I stopped all the gaps etc. I know it seems OCD but i wanna visually confirm i've got em all if I'm gonna go to this level of effort to fix it. Id rather not spray and pray... for lack of a better term .... so yeah for where the wall meets the ceiling I figure i'll need a plasterer in to make good regardless so may as well do it with good visibility and chop the top 10cm away and fill all the gaps , is what im thinking. For the skirts at the bottom, i've already packed the gaps between the skirt and the floor with rockwool, and then silicone sealed.
Gone West Posted February 19 Posted February 19 2 hours ago, EinTopaz said: I'm just uncomfy with the fact that I can't see what it's doing on the other side to be honest. You could use an endoscope. https://www.amazon.co.uk/SDYGDB-Endoscope-Borescope-Inspection-Waterproof/dp/B0B9T5MQ18?th=1 1
MikeGrahamT21 Posted February 19 Posted February 19 2 hours ago, EinTopaz said: I see your logic yeah. I'm just uncomfy with the fact that I can't see what it's doing on the other side to be honest. Not just because of the bulging, but also because I can't confirm that I stopped all the gaps etc. I know it seems OCD but i wanna visually confirm i've got em all if I'm gonna go to this level of effort to fix it. Id rather not spray and pray... for lack of a better term .... so yeah for where the wall meets the ceiling I figure i'll need a plasterer in to make good regardless so may as well do it with good visibility and chop the top 10cm away and fill all the gaps , is what im thinking. For the skirts at the bottom, i've already packed the gaps between the skirt and the floor with rockwool, and then silicone sealed. it’s a good plan if you don’t mind the mess and the replastering works. I wouldn’t bother with foam for this method though, how about buying a bag of plasterboard adhesive and take the section out, apply adhesive and stick some new board in, ready to be skimmed? Another option is bonding coat plaster and then skim on the small section I wouldn’t get too excited about a fix even by doing this, you will likely improve it but it won’t be perfect and will still leak air. I’ve done loads of work on my only room like this and still keep finding air coming through, but it is better than it was 2
EinTopaz Posted February 19 Author Posted February 19 (edited) 2 hours ago, MikeGrahamT21 said: it’s a good plan if you don’t mind the mess and the replastering works. I wouldn’t bother with foam for this method though, how about buying a bag of plasterboard adhesive and take the section out, apply adhesive and stick some new board in, ready to be skimmed? Another option is bonding coat plaster and then skim on the small section I wouldn’t get too excited about a fix even by doing this, you will likely improve it but it won’t be perfect and will still leak air. I’ve done loads of work on my only room like this and still keep finding air coming through, but it is better than it was I don't mind the mess really, we can cover the radiators, panels etc... and there's no carpet in there yet etc. So all in all i'm fine with it as as a strategy. I actually had two things in mind to try and fix it... so cut a section of the plasterboard out, 10cm near the top of the wall. then:- :- I'd have good visibility to see down the back of the plasterboard that's remaining from above. I could either foam or wool the bits inbetween the dot and dabs, from above. :- Run a solid bead of adhesive across where the plasterboard has now been removed, and put a new piece of plasterboard back on the solid adhesive. I'd originally thought maybe I need to cut a horizontal piece out across the top of the wall (red line), and also cut out 2 vertical pieces where the wall joints the adjacent walls (orange lines), but on reflection I think the latter is a tad overkill and not worth the effort/mess. Edited February 19 by EinTopaz
gravelld Posted February 19 Posted February 19 You can see the dabs in some of your thermal images. What's the surface showing 5.5 degrees - is that inside? 1
MikeGrahamT21 Posted February 19 Posted February 19 2 hours ago, EinTopaz said: I don't mind the mess really, we can cover the radiators, panels etc... and there's no carpet in there yet etc. So all in all i'm fine with it as as a strategy. I actually had two things in mind to try and fix it... so cut a section of the plasterboard out, 10cm near the top of the wall. then:- :- I'd have good visibility to see down the back of the plasterboard that's remaining from above. I could either foam or wool the bits inbetween the dot and dabs, from above. :- Run a solid bead of adhesive across where the plasterboard has now been removed, and put a new piece of plasterboard back on the solid adhesive. I'd originally thought maybe I need to cut a horizontal piece out across the top of the wall (red line), and also cut out 2 vertical pieces where the wall joints the adjacent walls (orange lines), but on reflection I think the latter is a tad overkill and not worth the effort/mess. If your going to that extent with vertical cut outs too, you may as well just take it all off and wet plaster the whole wall, plus that way you’ll get guaranteed results 1
EinTopaz Posted February 22 Author Posted February 22 On 19/02/2025 at 21:33, MikeGrahamT21 said: If your going to that extent with vertical cut outs too, you may as well just take it all off and wet plaster the whole wall, plus that way you’ll get guaranteed results What sort of tradesman do i need for this do you think? I don't fancy it myself. I'll let them advise on the easiest / least messiest way. Just not sure who I need.
EinTopaz Posted February 22 Author Posted February 22 On 19/02/2025 at 19:41, gravelld said: You can see the dabs in some of your thermal images. What's the surface showing 5.5 degrees - is that inside? On which image are you seeing the 5.5 degrees? It'll likely be inside yes.
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now