[IT]

Originally Posted by notorious

Very interesting Ian. How did you insulate exterior walls?

Well, good old building regs insist that on the new extension, that the cavity walls are insulated. I wasnt convinced about the full cavity fill foam type insulation as it didnt leave a damp gap, so asked my builder to do kingspan type insualtion slabs instead.

Reluctantly, he did, and in my naivety I was very pleased he was doing what I needed.

After hd' done his little bit of throwing together the extension brickwork and legging it, it dawned on me that in hindsight, he'd done a crap job. The insulation slabs were shoved in, not taped, not sealed and were essentually useless. Yes, they'd stop direct heat going outwards, but heat doesnt go out much, it goes up. So if you have loads of gaps, you just have a chimney effect that takes all the heat up to the roof, and out.

Plus, even if he'd done a mint job on the extension, it still left the rest of the house with regular 1979 uninsualted cavity walls.

I'm not convined by cavity insulation, that silly foam/worm type stuff they squirt in. Seems a bit hit and miss to me. No, I wanted something robust. (i do drive an A8 you know... lol)

So, 50mm of insulation was placed on the inside walls. All of them. I put up 25mm battons all the way round every outside wall, upstairs and downstairs, filled the void between the battons with 25mm kingspan, and then ran an interweved 25mm of kingspan across the top. All foil taped at the joints, running from the insulation of my concrete slabs right up the the kingspace layers I ultimately put on my upstairs ceililngs.

Its extreme, the whole house is tin foil box.

Allegedly, its been quite cold outside the past few days. Thank god I have temperature sensors to verify that, as honestly, I wouldnt know otherwise