Redbeard

Tony Cowling also has ISHS, I think. He described it in a recent AECB webinar. http://tonyshouse.readinguk.org/

Centre for Alternative Technology in Machynlleth did. The basis was experimental (and cheap, I guess!), so it (water-trickle solar roof over black-painted crinkly tin feeding a 100,000 litre - IIRC -thermal store which ultimately leaked) proved the concept very well. The store was a big hole lined with huge EPS blocks and lined with pond-liner. I believe the issue was that the liner used to extrude into gaps between blocks and pop! I believe the short-lived Earth Centre at Conisborough had an inter-seasonal heat store too, but I am not sure how well that worked.

1930s house: some render cracking may (or may not) be indicative of wall-tie failure/degeneration. Lots of firms out there, but does anyone have any recommendations from real-life experience in this (S. Yorks/N. Derbyshire) area? In the past I'd have done it myself but not feasible now. Thanks in anticipation.

There's a great difference between using a bit of air-tight foam for specific purposes such as air-tightness round windows and joist ends and foaming up a whole roof. I think it's the latter application that upsets Bldg Soc's rather than the very reasonable use of small amounts for small applications (though I could be wrong and they may be more twitchy than I thought!)

I had originally taken that as 'walls with a 4" cavity'. I suppose it could also mean ' 2 skins of 4(and a bit?) inch brickwork, with a cavity (width unspecified)'. What age is the house? I don't *think* I have ever come across a 4" unfilled cavity. They tend to be around 2" or even less. (I accept that anomalies exist. If you do have a 4" cavity then with graphite EPS bonded beads blown in you could possibly achieve a U value (unadjusted for (e.g) bridging at cavity closures etc.) of under 0.27W/m2K, which is none too shabby.

Hello! Can we assume that the exg masonry is rendered?

Hmm. Exactly what I was going to ask. I have used it a lot, but always hidden, so I have never tried to paint it. Anyone tried painting Orcon F?

Ventilation... 'Breathing Wall'

As @joe90 says, what you do may depend on whether the mechanism extends down that far and is fixed to that part. If it is not, how about trying to get hold of some 'plastic lumber' (think some park bench seats) and scarfing that in? Wood-rot problem gone, and I for one will probably be dead before the 'plastic weevils' (take that either way) have done their stufff.

I like to use rigid wood-fibre on a lime parge (air-tightness) coat. It's fairly DIY if you are quite handy and good at attention to detail.

Vermiculite boards. Do you live in an urban area? Do you have to travel a long way before you see any neighbouring properties? Do your neighbours have wood-burning stoves which make you cough on winter nights?

Can I ask what the pic above shows? Is it the PIR between the rafters, with tape entirely covering the rafters? I did 20-25 Victorian attic re-fits over the years and they followed a similar pattern: Fit insulation between rafters. BEIS Best Practice now suggests 50mm vent gap as compared to typical 25mm hitherto. So for typical 75mm rafters, 25mm PIR between rafters. Rafters carefully marked at top and bottom. Offer up 1200 x 2400 x 100mm PIR boards and fix temporarily - 3 or 4 fixings max - with long screws using a piece of slate lath as a 'washer'. Tape all joints and perimeters as VCL or, if desired, add a sheet VCL. Then offer up and fit 25 x 50 slate lath (that's what I used). You could take the view that a hole with a screw in it is not a hole at all, or take the more pessimistic view and pre-drill holes and 'gun' with silicone to form a 'grommet'. Then I would add 25 PIR between the battens if I did not want a service void. If I did, perhaps 25 PIR and a 25mm void would work. (??) No time for pics tonight but I will try to find some tomorrow and post them up. I rather more favour wood-fibre now if headroom allows. (It wouldn't have done in most Victorian attics I did). I'll post pics of that too.

I have not llooked at the price for vacuum panels (Optim-R) for a long time, and I had to remind myself re the thermal conductivity too. Kingspan say: ''OPTIM-R is an optimum performance rigid vacuum insulation panel (VIP) with a declared thermal conductivity of just 0.007 W/mK,'' If you really mean 40mm of VIP (not a composite board made of, say floorboard with VIP attached) then that would give you an R value of 5.7m2K/W, good enough for a U value of 0.175W/m2K even without adding in the 'base case' R value. That's not too shoddy! Compares with an R value of 1.81m2K/W for PIR at 40mm (U = 0.55W/m2K). IIRC re the price, though, you may need a mortgage - and (in ignorance of the specifics) I imagine you'd need some sort of (less insulative - wooden?) frame to sit them in. They also cannot be fixed through, or they become NIPs instead of VIPs.

Point tooken, to a degree, but water vapour permeability is often talked of as 'breathability', so the lay-up I described has 2 a/t layers and a 'breathable' construction (Brick/lime/WF/lime). Unless there is an inherent damp issue then in this example I don't feel I'd be risking trapping any moisture (but also I acknowledge myriad ways of cat-skinning!).

Fair point @joe90. I always try to go for excellent air-tightness inside *and* out - 2 bites of the cherry. When I was doing IWI NBT used to say the a/t layer was the final plaster layer. OK, but you deliberately sit the wood-fibre on a parge coat designed to make the wall air-tight, so why move the a/t layer at jcts? Hence I do both. (You have highlighted that I did not read the OP carefully enough, though. ;-( Re the original Q, with dpc only I'd worry about capillary action if you were relying on it for weather-tightness.

The dpc might provide a degree of weather sealing depending on whether it sits smoothly or gets trapped and twisted when the windows go in. It certainly won't do anything much for air-tightness. Compriband and/or FM330 or similar, and a/t tape.

If by 'gravel soakaway' you mean a French drain, they only really work with a perforated pipe at the bottom *and an exit*. A French drain without an exit is arguably a moat. Your text suggests a newly-laid path, but the pic suggests a not-newly-laid path. Can you clarify? How much have they raised the level?

Given the kit you are likely to have in a plant room I imagine there's no real need for fire-resistance, but if there were any risk I'd rate Fermacell over OSB. Have BC made any stipulations?

I take it there is plasterboard on the bathroom side of the 'tunnel'? Does it have a vapour control layer (VCL) on the cold side? If not, rip it out, install a really-well-taped VCL and re-plasterboard. Then build up from the cold side, filling any gaps with *air-tight* foam. Butt up tightly to any timbers, and at least one further layer over them. 150 - 200mm of PIR is not, in my view, too much. Keep all the joints tight, and tape them too, with decent air-tightness tape, not just foil tape. The existing does not seem to terminate very tightly at the top where it meets the rafters and the noggin. Make that bit better, and keep it all as tight as the btm of the proverbial duck.

Yes, it would mean you had wasted money on the Intello *if* you believe that several sheets of foil-backed plasterboard constitute an unbroken VCL. Since I don't believe it would anyway, stick with the Intello only.

I was very happy with Green Building Store windows and doors. 1st lot installed by GBS 10 years ago. Have not even thought of putting a paint-brush to them. 2nd lot there were a few logistical issues but I still like the windows! I have heard good things re Ecospheric, too.

Can't guess. Can you measure the gross ext wall area incl. openings and we can make an educated guess. If the original plaster is lime and is not covered in impermeable paint you can use that (augmented where it's 'not there' - between floors, behind skirtings etc). If there's any gypsum I would recommend that you take that off, and *then* do your lime parge coat. When I was doing WF IWI at 100mm it was North of £130/m2 incl basic joinery replacement, and that was quite a few years ago. The reason I say 'Gross' area is that working around and making good an 'interruption' can be as costly as fitting insulation to the same area.

I would suggest an 'Intelligent' membrane such as Pro Clima's 'Intello'. Expensive but good if it does what it says on the tin - and I have worked on the basis that it does!

How high - up the the roughcast? And replace with something else or leave it exposed? And what about the render beneath the crack/DPC? Sorry, I meant 'hack off the render *up to* just above the crack'.

Contrary to what the Building Regs would have you believe (DPC should be min 150 above ext gr level) rain in some parts of the country easily bounces up 300mm, particularly off hard surfaces. If I am 'reading' correctly 300mm is about the level of that waste pipe. I had taken the internal floor level to be below that, but is it? Or is it way up by the stepped-out roughcast?