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About hotnuts21

  • Birthday May 28

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  1. I think, and I need to research this more, there is some tape that I can put on the bottom of the joists, I can then run the VB up the wall and along the bottom of the joists sticking to this double sided tape, when I install the plasterboard it screws through the tape/vb and self seals the hole, but I need to look into it more, as its only a small area, it means I could also run it up into the skylight well too which is pretty big on a warm roof!
  2. Yep the flat roof has Alutrix600 vapour barrier on the deck, its the bit between the bottom of the joists and the bottom of the deck I was never sure about, whether we cut it round the joists and tape it to the desk of the flat roof. (warm roof buildup on top of the joists). Sounds like I might be onto something
  3. HI AliG, yes that was my worry with the Steel and one of the main reasons I posted on here. I did wonder if just putting insulation on the inside of the timber upto the flat roof would suffice, especially as i have some left over 150mm celotex. I can bring this right down to ceiling and seal all around it with illbruck FM330 air seal foam, I could also run the vapour barrier across the bottom of the joists as well as up the walls. I may well have to loose some space inside the room and insulate on the inside of those beams, we are using sheeps wool elsewhere so might use 50mm thick of that in a plasterboard box along the beam, else i may end up with cold spots on the walls. Its all more work and cost 😞
  4. This may be a silly question but is there a particular expanding foam I should use? One that maybe has better insulation values or expands a lot to ensure I fill the entire length of the beams?
  5. As they say a picture tells a thousand words, so I have attached some photos. I was scrolling through some pics of my warm flat roof build and realised that the end of the building has two uprights timbers which are effectively a cavity now as they are blocked from inside/outside and now the top. Im wondering if I should drill a hole one of these timbers and fill it with expanding foam?? Although they are in line with the roof/floor joist timbers, they will I presume cause a bit of an effect to the heat loss of the building? Also above all the doors and windows the erectors uses square metal box section for the lintels instead of timbers (Prob cheaper at the time) and so therefore again another cause for panic for heat loss and cold bridging. The outside of the TF shell is getting a 60mm thick woodfibre insulation, and I could insulate with PIR the inside of the timber headers (if thats what they are called) but I cant insulate the steel lintels on the inside as thats the plasterboard level. Could I also drill small holes along the steel and fill with expanding foam too? Thoughts?
  6. Dont know if it helps, but we purchased our skylight from Vario by Velux and it came with its own upstand, pre insulated, sized etc. All we need is a hole in the roof and the inside drops down into the hole with a vapour barrier. Paul
  7. Its a good point and one I think I have been wrestling with for a while including some loss of sleep nights. The extension will defo be airtight when its finished, but the rest of the house is a 1908 terrace with 8 fireplaces so it has challenges, however none of the windows have trickle vents. I have plans for most of the chimneys and we are planning to do the house up over the next 4-5 years so by the end of it, it will be pretty much airtight, I think what I have been looking for is a system that I can install now, but 'turn up' in the future as the rest of the house gets added. I could install the ductwork to 95% of the house now without any issues. But as im currently building two warm flat roofs, It makes sense to put the inlet/outlet in now too. I live by the sea so I always wonder how bad the air quality actually is here, but I like the idea of cool air in the summer too. As the extension is a kitchen, bathroom and Utility I am wondering if maybe I just put in a smallish single/two room system and spend the rest of the budget on a decent thermal store hot water tank as we now have solar and battery so switching to electric water might make more sense too. I think I just have more questions haha!!
  8. Hi All, I've had 3 quotes from some well known companies for my MVHR system, but since we started looking at it two years ago one of the quotes has jumped 56% and has taken it beyond our budget. So I can make sure I'm getting a good coverage of quotes (and knowledge/experience), can people recommend any companies they are happy with, this would be for design and supply as I would fit myself, but the design really need thinking about. Not sure if I'm allowed to mention the companies I have spoken too already, so wont. Feel free to PM/Message me if you would like to not post it publicly. One issue I'm having is where the inlet/outlet pipes go and what kind of sizes we are looking at. We live in a Terrace with 80cm thick stone wall so some of the walls are not really an option! Thanks Paul
  9. I think this is a more accurate makup of what we had ended up with.
  10. Yes, as above you need an OSB or similar racking board. In these types of makes up it typically goes on the inside as per mike wye. However it is breathable (although the least breathable of everything in the build up). We decided to add the external wood fibre board as an after thought, so the timber frame was already up and traditional with it on the outside. It is the point of failure/most likely to get damp/moist, but I spoke to Steico technical support and quite a few others all of who said it was fine to do it the way I did the risk was the condensation analysis, but providing we put a good Vapour barrier on the inside of the wall, it will be fine. Which kinda blows my mind because im using OSB for my flat roofs!!
  11. I was considering a SA before reading this thread 🤣 now I'm just confused. Out of interest @Nickfromwales where abouts in Wales are you based?
  12. I have a warm flat roof that abuts up against the second story of our TF extension. I cant seem to find any detailed information on how to attach the epdm to the TF wall at the abutement, and then which laps over what with the EPDM coming up the wall and the breather membrane coming down the wall. thanks Paul
  13. HI Dave, can you point to any info on lapping it down into the walls, im geniunely interested how this works, as its not something ive come across and cant get my head around how you go down below the deck. This video at about 2mins in talks about lapping it up the wall not down, into the roof structure.
  14. Were you able to lap the vapour barriers together, from the bit you insulated inside?
  15. David I think we are both on the same page, maybe just not explaining ourselves clearly ? Your quote above threw me, as the vapour barrier doesnt go inside the existing house, it goes on top of the lower osb under the insulation which is technically outside the house when your building it ? and then up the outside of the wall at the side/back. Ive watched all Steves (london roofer) videos so I hope im on the right track as I plan to install it exactly as he suggests ?
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