Redbeard

Which ones? I suspect 'put boards' should read PIR boards.

I am not clear what the issue is. Is this a house which you lived in before the works, which has a proven record of noise transfer issues from GF to FF and vice versa? If so do you get the impression it is (a)impact noise which is the main one, or (b)airborne noise. If the former I would not necessarily expect a big change, as much of the 'noise' could be transmitted through the structure via joist pockets. If the latter it may help. If there was not much of a problem anyway why bother? (Unless you are using the insulation for both sound and heat *and* you want to 'thermally compartmentalise' the house).

As you say the front looks difficult for EWI with the incoming power-lines. How would you deal with them? Lots of Red Tape there, I guess. Step-cracks above front GF window (are you happy the original problem has been solved before you 'box it up'?), questionable boundary (? - your porch roof seems to meet a line down from next-door's FF window cill, so is that the boundary?) Where, then, does the fall-pipe go once you have EWI'd? I think your idea to IWI may be less fraught. However if you were to EWI the front... If there is no soffit and you think it would look daft to extend your roof-line only, how do you deal with the EWI projection? 'Industry Standard Capping Details' (bits of bent alu gunged in silicone) have a limited life, particularly if they are of the 'downstand' variety. Measure carefully, outside and in, the height above the window. It is not unknown for EWI to stop before it reaches the height of the ceiling inside, in which case what do you do? If that were left 'un-treated' you could face a strip of mould at the top of the room. Internal 'downstands' can be done. Bring it down well below the line of the top of the EWI. I am probably not alone on here in not regarding 300mm as a huge lot for the loft. Assuming you are not storing stuff in there, and that you are using 'cheap stuff', why not use 400, or even 500mm? You'll only do it once. If you do that you'll probably find the biggest 'shortcoming' is then at the hatch. It's difficult to leave yourself a way in *and* achieve excellent insulation coverage and air-tightness. Get inventive!! I worry about the plan to IWI the gable wall in the garage, certainly at 100mm - with a lot of PIR on a wall giving onto soil. If you look at a Glaser-method condensation risk assessment for PIR (which you can get for free on many manuf'rs' web-sites), and the manufacturer's advice, you'll see that they require you to keep the 'outward path' vapour-open (by removing impermeable treatments inside and/or outside). That's because the VCL on the inside (if indeed it is functioning as a 100% effective VCL) blocks the possibility of any retained moisture in the wall coming back in. As far as I can see, if you block the path inwards, you have no moisture-loss path at all. I may be wrong, though. Enlightenment welcomed! I've written a lot. I hope it is useful - it is certainly meant to be. A lot of 'thinking-through' to do, I reckon. Do come back with Q's and comments. Perhaps ask Nottingham Energy Partnership (0115 985 9057) if they can recommend an assessor. A retrofit assessor course may well increase your knowledge level (of course I don't know how much you already know) but it will not necessarily (AFAIK) give you access to a measured survey model and software, so while it may help you to make a judgement it will not allow you to spit out 'numbers' - running costs, kWh p.a. etc). You can, of course, do that 'long-hand' if you have time, and I bet there are some free access models out there somewhere. Edit: Re EWI - do not automatically think you cannot go below DPC. You do have to think it out carefully and perhaps use different materials but it can be done - down into a French Drain. Caveats re where does the drain exit, have you just dug below the footings, etc., but with care it can be at least considered. I see countless examples where the EWI Co has dutifully avoided bridging the injected DPC which is 150mm at least above internal GFL - leaving a cold bit just behind the 120-year-old skirting...

Hi @Julestools. I don't know what mix was used. That was before my involvement. I am not a lime expert but I think I share your idea that something as rich as 1:2 or even approaching 1:1 might be required. I don't know if having it that rich has any downsides. (Come to think of it I have used lime putty when I want a really creamy mix. Could you do that?). Out of nosiness I note that you are proposing mechanical fix only. I take it this is probably onto existing gypsum plaster. Others (including specialist merchants) disagree, but having gypsum in a 'sandwich' always makes me a bit uncomfortable. I usually strip that off and do a lime parge coat, but then maybe I like making work for myself!!

Hi @flanagaj, I tried to send a private message, but I gather you cannot receive them. Have you intentionally disabled the PM function, or has it just disappeared and is this an issue for Forum mgt?

... and I was just about to write that too. PIR externally amounts, in my view, to a VCL on the wrong side of the 'sandwich' - and I wince every time I see a TV show depicting it. How about rigid wood-fibre with a scratch-coat of lime render before the battens and (?hit-and-miss?) larch?

I know someone who tried to use NHL for the same 'economy' reasons. I think the main problem was using it as the 'adhesive coat' behind the boards. As I recall it simply did not stick at all - not even the 'light tack' afforded by RK70. I don't think he ever tried it on the boards, since he had to buy RK70 for the 'adhesive' coat anyway. Particularly if you are doing it yourself and have not done a lot of plastering I'd recommend RK70. It is so 'forgiving'. Slow, in colder weather, but relatively easy for non-plasterers to pick up.

I think we need a pic of the other end (the end nearest the camera position, where the stairs open up and there is no wall on the L). Likely no problem spanning from wall to wall in the 'distance' of this photo (where the coats are), but then nearer the camera you only have one wall... Is there a 'stub' of wall behind the camera on the LHS so you can bridge across the stair opening?

I used to hate doing footings and blockwork in trenches, because I did not do it that often. However these were generally small - medium extensions where the footing job was too small to be of interest to a busy brickie. So I was really picky of my own work... So my out-of-plumbs' or 'out-of-squares' were tiny, as I was always pulling myself up - and checking again... and again... To lift a term (thanks @BotusBuild) you need someone who gives a sh1t - sounds like @BotusBuild knows the person. Good luck in the 2nd go.

Hmm. What does that out-of-plumb bubble represent? How far is it leaning in how tall? From LABC Warranty: "How far out of plumb can a wall be in the UK? Wall panels should be erected to the following tolerances: • +/-10mm from plumb per storey height. +/-10mm from plumb over the full height of the building. +/-3mm from line of sole plate, with maximum +/-5mm deviation from drawing". In pic 3 (with a slack line on top of the blocks) where was the line when the blocks were laid? Is this the brickie you were planning to use above ground?

Glad you've found a window of opportunity.

When you say 'partially' do you mean 'the roof, not the walls' or 'only some of the roof'? The former I'd say is OK, but if 'un-airtight' means 'breezy as owt' it probably won't gain you a great deal. If you do propose to insulate the roof can you get to the gables to drill ventilation holes in the gable at each end (you'll need a good few between each pair of timbers)? For minimal structural diminution you ought to drill on the centre line (75mm if they are 150 timbers, for example) but that limits the insulation you can get in. It could still allow 50mm though which (crudely) could drop the U value from say 2.0 to say 0.5W/m2K, roughly adjusted for the 'thermal intrusion' of the timbers. If you are pumping in heat it will reduce the heat loss. If you are expecting it to keep you discernibly warmer on a cold day with the only heat input being the c100W of you I doubt you'd feel a huge difference.

No-one (except me!) has yet picked me up on the fact that using PIR on the top would in effect act as a 2nd VCL where you do not want a VCL. If you substitute 30mm rigid (breathable)wood-fibre you'd get 0.1609W/m2K. I don't think BCO would quibble. I have no idea of the size of the job but it may be that if you took it outside the roofing job it may drop in price. How many m2 are we talking about? Possibly the trickiest bit of all will be removing the floorboards without excessive damage, but it can be done by punching the nails through the boards before you lift them. I did that on a 32m2 floor. We allowed for 20% replacement boards and got away with <5%.

Clarifications: 1. I should have said 'replace the floorboards' after adding the layer of PIR. 2. The VCL goes in 'hammock-wise' first, and the insulation goes over that - the mineral wool within the hammocks and the PIR on top.