Redbeard

It is hard to tell, but the base coat looks much too rough in parts for a 1.5 'gritty-coat' to 'hide'. The 'tramlines' simply should not be there. A little off-flat, maybe; tramlines, no. They should have been sponged out when the render was stiff but still 'moveable'. Of course we have not seen the whole surface but (assuming everything is now hard as a hard thing) the 'tramline bit' needs another coat, in my view.

Is there a nuance here in relation to the 'after completion PD'? @kandgmitchell rightly point out that your 'during works' use seems to be covered 'for the duration of operations ...' . Then it becomes 'un-PD', but would be PD after completion if you erected it again! If the Planners notice I wonder if they could require you to take it down in order to re-erect it?

I m a little confused by the first few posts. Isn't the easiest way (to find out whether the potential extra space exists) to take off the architraves and measure the masonry opening? If you want to be truly 'belt-and-braces' you could hack a little plaster off on both sides above the door to see by how much the lintel bears on the masonry each side. This would give you an idea of whether, in extremis, you could widen out the masonry opening without risk - a not inconsiderable task, BTW. Find the dimensions of your composite door *and frame* and if that dim is smaller than the masonry opening you are set to go. If not, you're not.

I think moss gets so much less of a 'key' on clay than concrete, particularly when the concrete is deteriorating. I wonder if you will have an issue at all.

Beware air movement in the cavity. I had mine insulated with 'bonded' (ha!) EPS beads to a questionable standard as we had found really significant air movement in the cavity when doing minor works prior to EWI. I am not convinced we 'got it' 100%, but the EWI would have been incredibly expensive external wallpaper if we'd not addressed the cavity issue. As @Mr Punter said yours does not look a promising front elev for EWI with the oriel, bays and porch. I worry about the standards on 'down-to-a-price' work, and I would want drawings of how they would address the bays etc. I have seen some aesthetically dreadful 'solutions' and none which avoided serious thermal deficiencies except where the contractor had removed the bay windows, resin-anchored threaded rod in and fitted new bays on top of the EWI. Very nerve-wracking till they are on and right, I would guess.

Have you had a structural engineer's report? You could argue that this quote means that you are not covered., but this covers damage to floors, and refers to external walls. You have an issue with *walls*, not floors! If you have not had an SE report do get one, and ask the insurers to tell you why they *won't* pay out.

They normally sit inside a socket on WBS but at the bottom of the socket on mine is a 'stop', so little chance of smoke. Like I have never had any).

Why not do it in an insulated plaster such as Diathonite? That way there is no separate insulation and plaster layer. If your proposed nIWI is PIR then Diathonite will not give you as much insulation value, but at least every bit is insulating, unlike a system with battens and plasterboards. PIR thermal conductivity 0.022W/mK and Diathonite around 0.039 IIRC.

I am not thinking of the floors putting pressure on the walls, but whether the change in floor structure in any way 'undermined' the internal walls. As it was suspended floors before that does not seem likely, as each wall would have its own foundation. As I asked above, what ('footings') foundations did the internal walls have?

Ooh err... How long had you had the house before you had the UFH? What were the floors before? What footings did the internal walls sit on? If you were in the house for a while before you had the UFH done it suggests some 'parameter' has been (inadvertently) changed.

Welcome, Until I read your last line I had a couple of thoughts as to what you might do, but the fact that you have already got 37.5mm board on (and for clarification, that's 25mm PIR, isn't it?) could weaken your bargaining position. The one experience I had with trying to argue the 'not-a-15-year payback' thing was that BCO insisted on a SAP assessment which, even 17 years ago, was not cheap. In that particular case it was complicated much further by the SAP assessor managing to 'prove' that it *would* give a 15-year payback (it wouldn't), leaving us with no option but to increase the depth of insulation! As regards the party wall, whether you can make the 'it's free heat from next-door' argument (and whether they can too!) may depend on the BCO's opinion. On the other hand it is not an external wall so I would ask the BCO to point out the specific section of the regs which requires party walls to be insulated as per external walls. As a 'negotiating stance' you may be minded to offer 'cloaking of a potential bridge' by returning the IWI onto the party wall for, say, 1m at each return. That will help your heat-loss a bit. Don't forget to cut back the plasterboard off the external wall IWI otherwise you have just built in another, albeit smaller, thermal bridge.

EPDM grommets

Yes, it probably would - an interesting thought to those who don't want to use trickle vents. More expensive, though, and one more 'moving part' (another - PIV - fan). (And come to think of it, surely one of the 'advantages' suggested for PIV is that you can just sit it in the loft, blow down onto the landing and then it finds the gaps on the gr floor? If you need to duct to dry rooms you may be getting as 'complicated' (in the eye of some 'beholders') as MVHR).

Are you sure it is not condensation? Hypothesis: Cold wall, cold (impervious) membrane - condensation on membrane; droplets run down and permeate both the surface of the concrete and 'pool' within the depth of the slab where the membrane has pulled away.

+1. I prefer dMEV but some prefer PIV. It is a personal choice. Swot up on the alleged advantages and disadvantages before you commit, and form your judgement based on te best info you can get.

"Tom from Wessex Metal Roofing came back to fit the down pies" Meat, potato and ...feathers? (Sorry! Couldn't resist it!)

Wondered about that!

If it's 4 inch you might get a U value of a bit over 0.2W/m2K. I wonder whether you would need to comply with the values in tale 4.2 or 4.3. That governs whether you need 0.3 or 0.18W/m2K. It depends whether it gets classed as improvement of an existing dwelling (it isn't one) or as a 'new fabric element in an existing dwelling' (well, it isn't one of those either!! I'd still go for a 0.18 or better target. It'll cost less to run. You could get the U value down with a little bit of IWI, but consider a condensation risk assessment first.

Can you do some of the work yourself? That's the real thing that helps keep costs down.

Do external insulation if you can!! Does mean you have a cavity, or is it just 9" (225mm) brick? If it's cavity then you'd want to fill the cavity first (preferably with graphite EPS beads) before you externally insulated, in case of air movement within the cavity. If doing IWI get an interstitial condensation risk analysis done, and consider breathable materials such as wood-fibre or cork rather than PIR. Crudely, you can insulate externally to about half the U value (twice the insulation) that you'd get ('safely' - from a moisture point of view) with IWI.

If you go for retrospective BC approval ('Regularisation', which used to cost 130 or 150% of the normal fee - can't remember which - as a sort of minor 'slap' for not doing it right 1st time) I think 2 Qs might be raised: 1. Is all the additional timberwork structurally sound? (You may need a structural engineer for that) 2. Did the roofer install any insulation at all? Since the 2010 revision of Part L, when insulation upon re-roofing 'became a thing', the 'norm' for areas over sloping ceilings (such as you have at the lower part of your roof) was (assuming 75mm rafters) 25mm vent path under slates/membrane and 50mm PIR friction-fitted between rafters. The gov't Best Practice Guidance (2021 or 2022, I think) now suggests a 50mm ventilation gap, which in the scenario above would give room only for 25mm PIR. As far as I can tell from your posts the roofer may have put in none at all, which is a pity, but on a practical level you might be able to 'offer' silly-deep (400, 500mm-ish) amounts of insulation on the flat ceilings to compensate.

Apologies! I had my eye off the ball for over a week. @marmic & others' suggestion of Compacfoam with the threshold sat on it is good, and almost exactly what I'll be using in a retrofit context for my external door following EWI.

I guess the extension is where the drain run is, at present (?). Assume that isn't too much of an issue unless it is shared with next door. I assume also that where the 9m arrow is is your land - to re-run the drain in...(??? )

Biggest problem I can see is that for your repair (unless the original contractor has the remnants of the coloured render they used) you could need: 25kg base-coat and a 25 ltr tub of top-coat (and thoretically some primer too!)

Welcome! How deep are your joists in the loft? I would expect the ground and first floor joists to be 150-175mm, but I would expect those in the loft (supporting only the loft insulation) to be 75mm-ish. If this is the case then your readiness to lose 112.5mm off the FF ceiling height might mean the top of the joists in the loft being pretty well exactly where they were before, not lower, giving you more headroom. *I realise now that I should not really have replied in detail here! (Otherwise 'intro posts' become detailed tech posts!)