Marv968

Yep, Section 75 if you have used a credit card. Ask your bank to carry out a chargeback if you've used a debit card (IIRC, you get a certain number of days to claim with chargeback, so if you have paid with debit card, look into it and contact your bank quickly!)

Rationel quoted the front door for my house as 0.59 W/m2k too, but I'm not going with Rationel. The company I'm ordering from (Allan Bros) are supplying an Outline front door with the U-value of 0.72 W/m2k.

Looks like there's a number of things that are unfinished to me. Perhaps some trim end peices required? The grinder scuffed brickwork is annoying.

From the Passivehaus truss document on Thermal Bypass (Thermal bypass risks A technical review September 2022) So perhaps once past the first 6 weeks, any additional shrinkage will be minimal? I know with Celotex the date and time it was manufactured is printed on the side of the sheets.

When I enquired about Rationel windows, I was told the factory they are made is in Poland.

Where are you going to buy the Soudatight LQ from? I asked my builders merchant for a price early last week, but they're yet to get back to me. I've looked into Liquid DPM as an alternative, but I can't determine if it is suitable either.

Also, another big one is that the U value of silicone is around 2.6 W/m2K, whereas Compriband or similar is around 0.048 W/m2K, which is substantially better. I'm not sure how you'd apply Compriband before the bricks a laid?. From when I've been looking into it on the house I'm building, it's either stuck onto the frame of the window just before installation, or pushed in after the window is installed.