Redbeard

Can you show us a pic with a little 'boat' spirit level on the cill so we can see the nature of the fall (or not)? I *seem* to see a fatter mortar bed at the back than at the front, which suggests a fall, but an accurate spirit level will be a better judge than my old eyes. I have used the EWIstore overcills with success.

'Renovation of a thermal element' is 'adding or replacing a layer'. The 50% is *of the relevant thermal element in the room you are in*, so if there are 2 external walls and you IWI them both, you have done 100%, so definitely BC approval required. Theoretically if you did 49%, 49% and 2% in separate tranches you could arguably do it 'outside the Regs'. However when questions are asked when you come to sell the purchaser or their solicitor may not understand the 'letter of the law' under which you carried out the works, and may ask for an indemnity of a Regularisation Certificate. Your walls and ceiling to unheated space would be treated separately if done at separate times, but for counting purposes the 2 external walls are 100% of the wall area and the ceiling is 100% of the ceiling area. I always get BCO approval even for IWI of 1 external wall since, if and when I sell, I would want to be able to wave the completion cert in front of the person who was trying to find reasons to reduce the price. 200mm of wool will not reach the 0.16 U value for compliance (Edit: It might, just, if the exg 200mm was 'extra special' sheep's wool with a (lower-than-mainstream-sheep's wool) lambda of 0.035W/mK) but if it was done at a time when 200mm did 'cut the mustard' then as you are not adding a layer or replacing a layer (the pl'bd) you do not *have* to add anything. I would if I were replacing the ceiling (and of course arguably at that stage you have to stump up the £180 or whatever (may have changed since last I did one) for a Building Notice).

Can I ask what you had there before? I think I understand that there was simply the existing opening - unadorned by frame or anything - and a conservatory bolted on the back. What was on the floor at that junction between room and conservatory - i.e. over the area in which condensation and mould is occurring? Hypothesis is that the brick was 'sucking' enough to disperse the condensation so that you did not see it as droplets. Then you put something else hard and not terribly insulated next to that area and *that* became the 'target area'. As I say, simply a hypothesis....

OP, forgive me if I have missed this, but where do you see the mould and condensation? Is it on the main frame members (perhaps the bottom of the uprights and on all of the horizontal members) or perhaps only at the very bottom of the bottom members? The former could suggest that the specific frame sections are much less well-insulated than many of us thought* and the latter that it's perhaps the cold floor cooling the frame and taking it below the dew-point, in which case replacing the course of bricks immediately below the cill with Compacfoam could arguably warm things up enough to address (I hesitate to say 'cure' as we do not know enough about the specifics) the worst 'manifestations'. *Do they still use galv steel reinforcement at the corners of bigger frames?

@fandyman sounds like a 'bowing-out' post. I was about to trawl back for/ask for further details of the condensation/cold, and exactly how it was manifesting. I thought I had read more of cold spots than of condensation of mould, but I may have skipped past a significant bit. If you're bowing out I won't trawl back/ask my Qs (which would have included what the issues were with condensation and mould on the old door. Edit: I think maybe you did not have a door there at all, as you had a conservatory.). Is the condensation forming on the frame and running down onto the screed, or forming on the screed, *not* on the uPVC? The more detail you can give the more help we can be. I wish you luck with it, whether you pursue it here or by other means.

I think the points being made by those who have responded to your OP suggest that, however regrettable it is, most window/door re-fitters do 'fit the hole'. In the absence of any other instruction (such as re thermal bridging mitigation, which might be included on an architect's or other professional's spec.) that's 'what they do'. If they have not 'fitted the hole' very well (the sealant is poorly-detailed or the opening lights do not 'kiss' the draught-stripping well) this can and should be amended. Then they would have done the job 'with reasonable care and skill', 'fit for purpose' (it's a door without draughts) and 'as described' insofar as their 'offer' probably said something along the lines of 'supply and fit XYZ door'. (What did it say?) If peripheral insulation measures had been promised and not installed then the CRA (of which I know nothing, TBH) may 'kick in'. Knowing that you are unhappy about the cold threshold I suggested a careful and painstaking 'stitching' job with Compacfoam or similar. That could be done (with caution - don't accidentally introduce 'droops' as others have said) but it would be an extra over and above (as far as we know) what was quoted for.

Deleted: Edit: I had not read @RedRhino's post above, so I had just effectively repeated their theme. Sorry!

Answers: 1. I doubt if any of us here would say it was acceptable but I suspect it is common. 2. Yes for me, and I guess for all of us here. 3. Not much, and yes. 4. I don't know. I fear that there's no obligation to insulate below a cill. I'd do it anyway, but whether Bldg Regs would *make* me do it, I think perhaps not, but not certain. The last patio doors I was involved with were sat on Compacfoam. 5. No, sorry. I think if I had been presented with what you have there I would be cutting out a brick at a time and replacing with something like Compacfoam - expensive but effective load-bearing polystyrene. I am sure there are lots of really good uPVC window and door installations. Unfortunately I have seen a large number of average-to-awful ones, so this detail upsets me but does not surprise me. Was the uPVC door a replacement of an existing door, or is that a 'dropped' window opening? The latter, I think, given the odd cuts on the bottom half, RHS. Edit: Thinking about it, the patio doors we did were in a wall with EWI, so the compacfoam was 'buried'. In your case you'd have a 'raw edge'. It's late, so I'll think in the morning how one might deal with that. How far above ground level is the external cill? If it is close you'll get a lot of splash-up. OK, it's not a timber door, but neither is it ideal. (And whatever the Building Regs say, rain splashed up more than 150mm in many areas!

Oh I do like the potato connector idea!

?1 or 2 IBCs, cut out as necessary.

Ah! Thank you! It did, however, get me digging for relative weights of alu vs timber frames, and I could find no general authoritative source. AI, however (which I don't rush to believe generally but which may be right in this case) suggests that alu and timber frames (the alu being hollow and the timber not until the CFBs get in!) are similar in weight. So I ask the OP, or anyone, where does the 350 - 450kg come from for a 4m2 window?

Thanks for that?! At least it encouraged me to check the relative weights of alu vs timber. From motorcycling days I always thought of alu as very light, but then I never rode a wooden motorcycle...Rest assured that I never have installed alu windows and do not intend to, so all is well from that point of view!

A question: ''350 - 450kg?'' I have just looked at the order conf for one of my windows - 3G timber approx 2.3m2 - weighs 82kg. Yours are nearly double the area, so say double that weight - 164kg. I find it hard to understand what gives you the extra 190-290kg. Or have I misread the Q?

Could you perhaps build them in plywood boxes like some do for EWI and fix back to both brick and block? In EWI the EWI would form the reveal, but in your case perhaps you could tape in airtight and waterproof tape over the ply 'end-grain' and cover that end-grain and tape with, say, 25/ 32mm scotia moulding?

Sorry, did not spot this till now. I kept the OSB - it was anti-racking, too, and stapled the Intello directly to it. A/T tape over each staple...