Today has been all about insulation. The builders have been making good progress with the PIR in the attic - more on that below. I've just ordered another £180 worth of air-tightness tapes and sealants from Green Building Store, which should arrive tomorrow, ready to start taping on Monday. And I've also been costing out the VIPs (that's vacuum insulated panels) for the internal walls in the ground and first floor rooms, at the front. VIP is the only thing that can get us the required U-value in minimum thickness, but not without difficulties, in terms of needing battening (recommended in phenolic foam, but still, relatively, a cold bridge) and danger of puncture (ruining performance) both during installation and by occupants of the building. Hopefully the costings should come through by the end of tomorrow.

As I mentioned, the PIR installation has been proceeding: they've got most of the first layer (25mm between rafters) in, started the second (75mm) layer at the rear, and completed this and on to the third (75mm) layer at the front. The builders came up with an unusual-looking, though effective method of holding the third layer up to the second, whilst the adhesive cured:

Overall, both Andrew and I are pleased with the standard of the insulation work. However, there have been a few issues, the worst of which is this:

Needless to say, I need to have a word with the electrician when he comes back on-site on Saturday!