Withington Co-operative Eco-house - vip

Discovering dry rot

Robert — Mon, 02 Sep 2013 22:30:52 +0000

Today I was taking measurements for the VIPs (vacuum insulated panels) that we will be using to insulate the front elevation, at ground and first floor levels. VIPs are made to size at the factory and cannot be cut on-site - hence careful measuring is required.

When I took off the plaster above the front door frame, I discovered that the lintel above the door opening had suffered from dry rot. This means that we've now got unexpected remedial work to carry out: the lintel will have to be cut out and replaced, and the area treated with anti-fungal chemical. The good news is that the rot is localised and largely historic (most likely due to former water leak from the bathroom above), the lintel in the outer leaf is stone and thus unaffected, and this particular wall doesn't take any load from upstairs floors. Meanwhile, the builders have propped it up with a "strongboy". They had already cut out the rotten wood by the time I got to take this photo:

The top floor is very nearly ready to be plastered now, so the builders will soon be moving down to the first floor; hence why I am finalising the VIP order now.

Insulation again

Robert — Sat, 10 Aug 2013 22:21:07 +0000

Today I went to the house because I'd agreed to meet the electrician on-site, to go through a few issues regarding cable routes etc.

Whilst I was there, I noticed that the builders had completed the insulation in the front attic room, ready for beginning the taping on Monday morning (the back rooms still need another layer). However, although they had mainly done a good job, where they had stuffed the void behind the purlin with quilt insulation, it had pushed up the 25mm PIR boards, compromising the air gap for ventilating the roof:

Something to take up with them on Monday, no doubt. They've also taken delivery of a pallet-load of 9mm plasterboard, which seems a bit premature to me considering they haven't even started the taping yet, and still have the bottom layer of PIR to put on at the rear.

Meanwhile, the costs are in for the VIP - significantly cheaper than Spacetherm. I've been reading various things about VIP and the main concern (apart from vulnerability to puncture both during installation and in service - both of which I think we can mitigate on this project) is degradation in performance over time. Need to clarify the situation with the suppliers on this issue.

More insulating

Robert — Thu, 08 Aug 2013 23:02:09 +0000

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!

Withington Co-operative Eco-house - vip

Discovering dry rot

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Insulation again

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More insulating

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