pmcbythesea

Moving on then.......at some time in the faraway distant future existing timber soffits and facias will be replaced and that's an opportunity to put in proper air-flow. However in the meantime, I am inclined to go round existing soffits, drill holes in them and put in these: https://www.amazon.co.uk/gp/product/B004E5HB5Y/ref=as_li_ss_tl?ie=UTF8&tag=daniweadroof-21&linkCode=as2&camp=1634&creative=19450&creativeASIN=B004E5HB5Y Has anyone done that, come across any issues?

Thank you, that's very helpful. I was thinking of sticking some pipes in. I guess in 1977 people didn't think too carefully about loft ventilation.

1977 bungalow with 100mm fibreglass loft insulation between joists and now an additional 200mm fibreglass insulation on top of that across the joists. At roof edges where roofing timbers meet the ceiling joists and external walls, it was very leaky - it was possible to see right down to the soffits and the loft space was pretty well ventilated by accident rather than design. Timber soffits with no ventilation built in but over the years they seem to have shrunk back from the walls giving airflow to the loft. Now that extra insulation has gone in, the extra 200mm has blocked off the views down to the soffits and therefore the airflow. And the only other ventilation in the loft is via an odd tear or two in the roofing felt. No breathable membrane, no ridge ventilation, etc. Question is do I re-open at least some of the previous gaps down to the soffits (i.e. take the extra insulation away from the edges)? It is worth pointing out there is a cold water supply tank up there which is insulated but could be prone to freezing in very cold weather if there is a significant airflow through the loft.

Aluminium tape from Toolstation (other suppliers are available) does for me but I've only been using it round window reveals on top of Spacetherm.

We are approaching internal insulation of external walls (1970s bungalow, upgrading thermal elements) and our BCO suggested we think about window reveals as potentially the weakest link in terms of insulation (walls are to have 25mm Celotex between timber battens on 18mm dense plaster on engineering brick, I know it's not much but there's no room for more). The reveals will allow a maximum of 15, maybe 20mm of Fermacell 10mm and insulation plus vapour barrier. It seems a no-brainer to me to go for 5mm (10mm where there is space) Aerogel Spacetherm, pricey though it is. BCO seems happy with this, he certainly didn't want us removing existing plaster which would destroy the integrity of the existing reveal. So Spacetherm glued to the reveal, vapour barrier on top, then Fermacell fixed through plaster to internal brickwork. Any other possible options????

Yes, that was what I understood too. However we've gone with the BCO and stuffed glassfibre around all the wall edgings so we should be draught-free. Now that the flooring is down it does feel more comfortable in that room (kitchen) - there was certainly a strong airflow under the joists and there's no sign of that now.

Hmm, that's interesting, pleased I'm not the only one.

1977 bungalow, suspended timber floor over site concrete 75mm below joists (plumbers just love crawling about in there). Okay, so we've pulled up the floorboards, cleaned up underneath (yes, really!), lagged the plumbing with extra glass fibre, and put in 100mm Celotex GA4100 between the joists with more glass fibre stuffed into any gaps around the perimeter. Original idea was to tape across joists and all Celotex joins but when we looked at that we thought a vapour barrier would be easier. (Ha, if only.....) Anyway, our friendly local BCO was out to have a look and I posed the question do we really need a vapour barrier. A certain amount of discussion ensued involving possible condensation (would be under the Celotex and just drip onto the subfloor) and any above floor leakages. The eventual conclusion was not to fit the vapour barrier because potentially that could just act as a pond collecting water which would rot flooring, kitchen cabinets and the like because the water would have nowhere to run. I think I am okay with that but I just wondered what you may think? It seems this goes against much of the advice I have come across.

Thanks guys. We're actually in East Yorks.

A welcome successor to ebuild. I feel whole again! Looking forward to learning from everyone's experiences and rants and raves. I am in awe of some of the projects. History: Wiffy & I self-built 12 years ago in SW Scotland. Have now moved south and east (it's sunnier) and have a 1977 bungalow renovation. Various things done but now into upgrading thermal elements. It's small fry compared to what most other people are attempting but here's a sample....