Mr Punter Posted January 14, 2021 Share Posted January 14, 2021 Will a can of expanding foam not fill that? Bear in mind that if you use it you will struggle to get to any of it later. Also it can push stuff about as it expands. Link to comment Share on other sites More sharing options...
AliG Posted January 14, 2021 Author Share Posted January 14, 2021 4 minutes ago, Mr Punter said: Will a can of expanding foam not fill that? Bear in mind that if you use it you will struggle to get to any of it later. Also it can push stuff about as it expands. This is what I am grappling with. For a modest area I don’t mind using foam but the area to be filled here is around 400x250mm with the duct through the centre of it. Most likely it will never be seen or touched again so I should just get spraying. I just need to think about it. The builders have actually parged the blocks and sealed the edges with foam just along from here. Seems rather pointless when you have left a gaping hole right next to it! There was a bigger gap in the eaves that I had to fill. There I cut pieces of PIR and then foamed around them so I am considering that option. Access to do this would be difficult though and even without this I am considering that I might need to bite the bullet and take down more of the ceiling. Because the ceiling is suspended and the duct is in the way it will be pretty difficult to make sure I have got everywhere filled. Link to comment Share on other sites More sharing options...
Mr Punter Posted January 14, 2021 Share Posted January 14, 2021 I would give it all a spray of water to moisten slightly, get the foam gun nozzle right to the back and squirt in. Don't apply so much that it drips or falls out. You may need to do a few passes after the first has partly cured to make it fill properly. 1 Link to comment Share on other sites More sharing options...
AliG Posted January 15, 2021 Author Share Posted January 15, 2021 (edited) I had to cut a bigger hole to get at it all and have started to fill it in. I have started with expanding foam right at the back where the pipe comes through the PIR and where the PIR goes around the corner behind the wall to the side of the MVHR duct. My plan is to do it in two layers, one sealing up the PIR and another one in front inline with the missing blockwork. I have made a start on the rear layer and am going to let the first can of foam expand and dry before I see if I have missed anywhere. I have bought 10M of 6mm ID 8mm OD pipe to attach to the foam cans as I have had the issue elsewhere that you cannot get the can close enough to where you need to fill. The is exacerbated by the cans needing to be upside down. If you attach a couple of feet of flexible pipe you can keep the can out of the way. The first time I did it I thought I would clean out the pipe but that was pointless, so I bought 10M from EBAY on the grounds that I will use about 60p worth and just bin it each time I need to get a can of foam into an awkward space. I also recommend proper disposable latex gloss and not the thin ones supplied with cans of foam. The foam comes through these as they have little breathing holes. I took a picture with my hand to give you an idea of the size of the hole in the inner blockwork. If you look at the pic you can just see the block to the left of and in front of the ducting and the edge of the block to the right of the ducting. This whole section of inner leaf is missing. It was above the ceiling but the ceiling has various penetrations for lights etc and also connects to the area behind the WC where the cistern is. It must have had quite the impact on the airtightness test I assume. Between the cupboard and the WC there are 5 lights, 2 sensors, 2 sockets, the WC wall fittings and the WC flush plate all where air can get through. Edited January 15, 2021 by AliG 1 Link to comment Share on other sites More sharing options...
Gav_P Posted January 15, 2021 Share Posted January 15, 2021 5 minutes ago, AliG said: I took a picture with my hand to give you an idea of the size of the hole Depends if your hands are like Trumps?! 2 Link to comment Share on other sites More sharing options...
AliG Posted February 9, 2021 Author Share Posted February 9, 2021 The big hole is all filled in, but there was still a bit of air getting in from somewhere. If you look at the plan I posted the issue continues to be the interior cavity spaces. Basically the roof of this area is a single concrete slab.The builders have sealed what they thought were the three outside edges. But the inside edge between the hall and the cupboard/WC is open to the cavity between the two layers of Porotherm. As they considered this an inside wall they didn't seal the edge of the slab. In the cupboard I have filled it between the hole I cut in the corner and the hole the MVHR duct comes through. No ready made hole in the WC, so I have peppered the ceiling with holes and sure enough as soon as I cut the first one I could feel the draught. There is around a 10mm gap between the Porotherm and the slab all the way along above the doors. In the very corner I knew the water pipes came through the wall into the WC and this was sealed. The frame that holds the ceiling sits in front of the gap and in some places there is only a 6 or 7m gap. So the 8mm PVC pipe I have been using attached to my foam is too thick and I will finish it off when some 6mm comes. I was almost done in the cupboard when I got a bit too enthusiastic with the foam and blew the pipe off. Do you like my new designer shirt? As I think I said this little area has always been the coldest part of the house but I didn't know what the problem was. I even got the builders to take down the WC ceiling, but they still didn't figure out the gap to the hall side was the problem. I will be very happy to have this fixed. Link to comment Share on other sites More sharing options...
Mr Punter Posted February 9, 2021 Share Posted February 9, 2021 Well done for all your efforts. I think this suggests that it is worth having an air test after first fix, before plasterboarding. Link to comment Share on other sites More sharing options...
AliG Posted February 9, 2021 Author Share Posted February 9, 2021 3 minutes ago, Mr Punter said: I think this suggests that it is worth having an air test after first fix, before plasterboarding. Absolutely, this would have made things much simpler. Luckily most of the problem areas have been in places I can get to with a bit of effort. I think a lot of the areas were probably not impacting heating bills much. This one was though as often this was the only place in the entire house where the heating was on. Indeed I had to put an extra wireless thermostat in the WC as it was on the same thermostat as the hall as was often cold when the hall was fine. This is more an impact in spring and autumn. I have one big job which I hope the builders will tackle, insulating the study wall, but I cannot get them in due to COVID. After the WC the study is the next place where the heating is on the most and as it is a bigger room it might be more impacting heating bills. The one other place that could be improved is the chimney breast in the kitchen, but I just cannot see how I can get the access to do it. If the ceiling fixes nicely in the WC I might have to do the same thing in the kitchen. It does not seem to be having the same impact on heating as I think the cold air is mostly contained within the chimney breast. Then I will get the air test done again and see what difference it has made. It will be interesting to see if a better air test result actually corresponds to lower heating bills. Link to comment Share on other sites More sharing options...
Mr Punter Posted February 9, 2021 Share Posted February 9, 2021 It is no only the heating bills but comfort from lack of draughts and annoyance that you have spent a lot of time and money for it to be slightly tainted by something so relatively easy to address at an earlier stage. Link to comment Share on other sites More sharing options...
AliG Posted February 9, 2021 Author Share Posted February 9, 2021 Funnily enough I was thinking of posting a thread earlier today about how people's houses feel in the cold weather. It is very noticeable that you cannot really tell from inside the house how cold it is outside. I think that 3G windows are a big part of this as you don't feel any colder next to them than next to a wall. I remember my parents had a house built 30 years ago where the front door was part of a large double glazed screen. The whole area around the door was absolutely freezing when it was cold outside and we had to put a curtain over it to try and reduce the impact. A friend of ours posted on Facebook the other day that it was -2 outside and their heating could not keep the house at a comfortable temperature, I think their house was built in the 70s. Despite the airtightness we don't have any draughts except in the WC. Almost all the places I have been fixing have been unheated and ancillary rooms like the laundry room or eaves storage. Luckily it is often a problem of bad detailing, I think. I do, however, notice doors will move when it is windy outside and this seems to have fallen since I filled the big hole in the cupboard in. I suspect that if I get the rest of the gap here filled in and then the plasterboard back there will be a further improvement. The WC suffers from a perfect storm. It is almost entirely outside walls as it juts out from the house. It is on the north side of the house with a small obscured window so no solar gain. It doesn't have insulated plasterboard as it is not rated for the weight of the tiles and it is entirely tiled which makes it feel cold. I still knew there was an airtightness problem here, I just couldn't find it. The flush plate cannot be perfectly sealed to the wall and the cistern is boxed into an area that is open up to the ceiling, I could feel cold air coming in here and the small lights in the wall alcove. But ultimately the whole area is less than 1% of the house so it probably wasn't impacting things too much. Link to comment Share on other sites More sharing options...
jack Posted February 9, 2021 Share Posted February 9, 2021 6 minutes ago, AliG said: It is very noticeable that you cannot really tell from inside the house how cold it is outside. Yup, exactly this. It could be -1 or 10 outside and I can't tell from standing beside a window. Link to comment Share on other sites More sharing options...
Gone West Posted February 9, 2021 Share Posted February 9, 2021 35 minutes ago, AliG said: It is very noticeable that you cannot really tell from inside the house how cold it is outside. I think that 3G windows are a big part of this as you don't feel any colder next to them than next to a wall. We have had snow sitting on our bathroom roof window for three days and it's 24C in there. Triple glazing is excellent. Link to comment Share on other sites More sharing options...
Gav_P Posted February 9, 2021 Share Posted February 9, 2021 5 minutes ago, PeterStarck said: We have had snow sitting on our bathroom roof window for three days and it's 24C in there. Triple glazing is excellent. Christ, don’t tell Mrs @Onoff that it’s possible to have a bathroom at that temp! ? 1 Link to comment Share on other sites More sharing options...
Iceverge Posted February 9, 2021 Share Posted February 9, 2021 43 minutes ago, AliG said: Funnily enough I was thinking of posting a thread earlier today about how people's houses feel in the cold weather. It is very noticeable that you cannot really tell from inside the house how cold it is outside. I think that 3G windows are a big part of this as you don't feel any colder next to them than next to a wall. I remember my parents had a house built 30 years ago where the front door was part of a large double glazed screen. The whole area around the door was absolutely freezing when it was cold outside and we had to put a curtain over it to try and reduce the impact. A friend of ours posted on Facebook the other day that it was -2 outside and their heating could not keep the house at a comfortable temperature, I think their house was built in the 70s. Despite the airtightness we don't have any draughts except in the WC. Almost all the places I have been fixing have been unheated and ancillary rooms like the laundry room or eaves storage. Luckily it is often a problem of bad detailing, I think. I do, however, notice doors will move when it is windy outside and this seems to have fallen since I filled the big hole in the cupboard in. I suspect that if I get the rest of the gap here filled in and then the plasterboard back there will be a further improvement. The WC suffers from a perfect storm. It is almost entirely outside walls as it juts out from the house. It is on the north side of the house with a small obscured window so no solar gain. It doesn't have insulated plasterboard as it is not rated for the weight of the tiles and it is entirely tiled which makes it feel cold. I still knew there was an airtightness problem here, I just couldn't find it. The flush plate cannot be perfectly sealed to the wall and the cistern is boxed into an area that is open up to the ceiling, I could feel cold air coming in here and the small lights in the wall alcove. But ultimately the whole area is less than 1% of the house so it probably wasn't impacting things too much. Have you DIY rigged a blower door fan? For less than £50 it's like a 6th sence when you're draft hunting. Tremendously satisfying too. Link to comment Share on other sites More sharing options...
epsilonGreedy Posted February 9, 2021 Share Posted February 9, 2021 Going right back to the start of this thread I remember thinking did the assessor choose the right unit of measure for the internal size of the house. I recall the OP's house is a bit of a mansion and if feet were recorded as meters the large house would be a plausible small house and so the air leakage factor would be inflated. Link to comment Share on other sites More sharing options...
Onoff Posted February 9, 2021 Share Posted February 9, 2021 16 minutes ago, Gav_P said: Christ, don’t tell Mrs @Onoff that it’s possible to have a bathroom at that temp! ? She has in fact seen Peter's house. Still doesn't get the no pain, no gain thing. Until she lets me dig the floor up in the adjacent room it will continue to be effing cold in there. Or she can move the tonne of crap in the loft (all hers) and I'll sort the body dryer. Link to comment Share on other sites More sharing options...
SteamyTea Posted February 9, 2021 Share Posted February 9, 2021 58 minutes ago, jack said: Yup, exactly this. It could be -1 or 10 outside and I can't tell from standing beside a window. That's interesting. There is a school of thought that is convinced that there are huge radiative losses via glazed areas, "because it radiates to space". I have never bought into it and always put it down to poor glazing. Link to comment Share on other sites More sharing options...
AliG Posted February 9, 2021 Author Share Posted February 9, 2021 (edited) 33 minutes ago, Iceverge said: 1 hour ago, AliG said: Have you DIY rigged a blower door fan? For less than £50 it's like a 6th sence when you're draft hunting. We had an airtightness test done and spent a couple of hours looking for issues. Tbh a lot of them were places I had guessed were going to be an issue. What was surprising though was how much air was coming through some of them. I am hoping that half a dozen large holes and issue areas were the majority of the problem. 17 minutes ago, epsilonGreedy said: Going right back to the start of this thread I remember thinking did the assessor choose the right unit of measure for the internal size of the house Sadly I think it was correct. I did notice he had missed one or two of the mvhr vents afterwards though. 12 minutes ago, SteamyTea said: 1 hour ago, jack said: That's interesting. There is a school of thought that is convinced that there are huge radiative losses via glazed areas, "because it radiates to space". Our hall is almost entirely glazed to the north side and double height. It doesn’t seem to take any more heating than other parts of the house (suggesting it is fact the air leakage that is the problem in the WC) I think that the benefit of triple glazing is larger than the u-values suggest. It may simply be that it removes cold areas and people end up over heating their houses to compensate for the coldest spots. I might get the IR camera out later this week when it is forecast to be -7/-8 as it will be interesting to see the impact. Edited February 9, 2021 by AliG 1 Link to comment Share on other sites More sharing options...
Onoff Posted February 9, 2021 Share Posted February 9, 2021 38 minutes ago, Iceverge said: Have you DIY rigged a blower door fan? For less than £50 it's like a 6th sence when you're draft hunting. Tremendously satisfying too. So this is a blower rigged to blow air into the house, set in a sealed door or window aperture? The idea being it "pressurises" the internal space? Silly question maybe but how do you see/feel the draught? Wet finger, bit of paper to blow in the "breeze"? Link to comment Share on other sites More sharing options...
dpmiller Posted February 9, 2021 Share Posted February 9, 2021 no , set to depressurise. easy to feel draughts then... Link to comment Share on other sites More sharing options...
AliG Posted February 9, 2021 Author Share Posted February 9, 2021 They depressurise the house, so if there are any holes the outside air gets sucked in. When we did it, the outside temp was about 3C, so you could very easily feel the cold air. It would have been a lot harder in the summer. The guy had a puffer that puffed smoke/chalk dust to detect air movement. I have tried smoke matches but they do not work anywhere as well, they produce too much smoke. It was noticeable that cold air was drawn in through lots of very small gaps where I had never felt a draught at all so it is a pretty severe test. Link to comment Share on other sites More sharing options...
Iceverge Posted February 9, 2021 Share Posted February 9, 2021 (edited) 7 minutes ago, Onoff said: So this is a blower rigged to blow air into the house, set in a sealed door or window aperture? The idea being it "pressurises" the internal space? Silly question maybe but how do you see/feel the draught? Wet finger, bit of paper to blow in the "breeze"? It's a car radiator fan in a sheet of OSB in a window opening. Tape it in ( don't use airtightness tape, you'll never remove it!!) And connect it's wires via crocodile clips to your car battery. Depressurising the house is best as you can feel drafts as air rushes in through cracks simply with your hand or a candle flame will flicker for tiny ones. Subjectively I reckon we were easily generating twice the pressure difference with our test fan compared with the official blowerdoor. Edited February 9, 2021 by Iceverge Link to comment Share on other sites More sharing options...
SteamyTea Posted February 9, 2021 Share Posted February 9, 2021 (edited) 27 minutes ago, Onoff said: Silly question maybe but how do you see/feel the draught? Wet finger, bit of paper to blow in the "breeze"? Number of ways, manometer would do it. Or a couple of BMP280s https://www.bosch-sensortec.com/products/environmental-sensors/pressure-sensors/pressure-sensors-bmp280-1.html I am using some BMP280s to see what the temperatures are doing. Easy to rig up once you realise that it is possible to add extra I2C pins to an RPi. Sensor Number, Date and Time, Temp, RH, Pressure i2C4,09/02/2021 18:12:33,15.14,37.1864298623,986.316160323 i2C4,09/02/2021 18:13:32,16.75,36.0736943753,986.391397008 i2C3,09/02/2021 18:13:32,0.81,69.812819981,987.416998524 i2C3,09/02/2021 18:14:31,0.78,70.1470805963,987.875455501 i2C4,09/02/2021 18:14:31,18.15,33.8904554416,986.36425019 36 minutes ago, AliG said: later this week when it is forecast to be -7/-8 as it will be interesting to see the impact Should be cold enough, fro long enough, to establish your kW.K-1 numbers, then you are only one step away from a predictive system. Edited February 9, 2021 by SteamyTea Link to comment Share on other sites More sharing options...
Onoff Posted February 9, 2021 Share Posted February 9, 2021 I've got this: Link to comment Share on other sites More sharing options...
SteamyTea Posted February 9, 2021 Share Posted February 9, 2021 Just now, Onoff said: I've got this: You buy that off @pocster, wash it thoroughly, in vinegar and carbolic soap. 1 Link to comment Share on other sites More sharing options...
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