gravelld

Doesn't it depend on the dwelling's current overall air permeability? If leakage is high enough from throughout the property it might not require an extra vent.

Bear in mind that spray foam insulation is getting a very bad reputation amongst the normies out there. It's mentioned as the reason for a lot of collapsed house sales because mortgage companies and surveyors can question it. That's not a good reason, of course, just that there may be growing anecdotal feelings toward it that you might find challenging later.

Icynene?

Christ that video is so disappointing. This is exactly what people are talking about when we question the knowledge and skills gap amongst trades.

walltoroof.thumb.jpg.9e8fff6f087d3bdfcc7f4a8e526e48af.jpg - looks like there's a projector or something in the photo...

You can see the dabs in some of your thermal images. What's the surface showing 5.5 degrees - is that inside?

It can definitely be over-used. Cheaper foams don't deal well with movement. Look for the flexible ones, like Soudal Flexifoam. They allow some degree of compression and reshape. But think of it more of a gap filler for other measures than an air tightness provider, as such.

I meant that as a specific example - it might have affected the previous administration. The current one might be affected by unions, for example. Don't want to sound like a downer, just repeating what I've observed. I'd like to think you're right.

This is constantly done - review the select committees and various research committees investigations on the .gov.uk site. The issue is the annoying tendency of people ("stakeholders" i.e. including non humanoids like corporations etc) with different incentives and different goals also chipping in with quite different recommendations. Government, quite reasonably, cite the impact on economy and jobs as being as important, for example. Then, between a crusty self builder and a smart, well spoken, polished type flashing some credentials, who do you think gets called to give evidence and shape policy? For example, in a call-for-evidence on housing performance, we can all chip in with how we think all new homes should target Passivhaus levels of performance and give some good engineering and scientific evidence for our opinion, but all the Persimmon guy who employs thousands and donates to The Party needs to do is rub his fingers together. 🤌 It's the age-old story of lobbying.

Can you not get access to the eaves, to pour them in? 10:1 water:PVA was suggested here: http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13384

I don't know why there's such a fixation on the heating system for new build. If they were built properly it really wouldn't make much difference because the heat demand would be so low. It would be better to just fix the problem at source.

Do both, remove the bottom of the roof covering and and run the EWI over the top of the cavity to touch the loft insulation (assuming you have a cold roof). This also assumes enough overhang, but you can also kick out the bottom tiles to give you more space, and/or chamfer the top of the EWI. Remember you want that continuous insulation. Also consider plinth insulation. The only other thing you might consider is a different route to 'sticky and fixings' EWI and do something more like Larsen trussing, fixing an outer board and filling with loose fill instead. However this is much less done in the UK and will probably be consequently more expensive.

Sorry - what does this mean? 😕 Thanks for the advice - some wise words.

Given that the very nature of this forum is that of one for self builders of varying levels of experience, it might be best to describe why something is a "ludicrous idea". Not everyone understands all the steps and risks involved in what turns out to be a complex project.

Hmmm. Ok, that rings a bell. Looked at them many years ago.