Redbeard

Welcome. A library near me has kept the original ducting from the gas-fired warm-air system and is now running it with an air-to-air HP. I understand it is performing really well. Of course ASHP does not do domestic HW but I think the standard Johnson and Starley WA boilers require a separate water-heating appliance anyway, don't they? You can get 'heat pump cylinders' with an integral exhaust air HP.

Hi. Are you envisaging that the draught-proofing and insulation will be the main 'driver' for reducing heating costs? I don't have a HP myself but the (anecdotal) experience of some people I have worked with has been that (all other things - insulation status etc - being equal) they may not spend *more* on heating with a HP, but they do not necessarily spend less than with the previous fuel. I realise tariffs and 'running style' will be big variables as, of course, will be the CoP.

Re garage/habitable space I cannot remember whether there is different treatment for a sheltered (unheated but not external) transition such as this. If it's treated as external then you probably want 0.3W/m2K. Can't answer that one, but can note that 100mm PIR in a vaulted ceiling is unlikely to meet the 0.16W/m2K target. (Was this approved after June(?) 2022? Could be 0.18 if before that date. 100mm won't meet either of those targets. BCOs can offer leeway, but as I understand it they do not have to. If you have not negotiated a waiver before now you may not be in a strong negotiating position. On the other hand they might take the view that you're pretty close and let you leave it as is. Do you really want to take tiles off? Why not cut out say 300mm sq of ceiling (bevel the cuts so you can glue it back) then just take out a core of the insulation big enough for BCO to get their tape measure in. Keep the core to glue back and foam-fill before taping as VCL.

Unless the 2022 revision changed it, and I don't think it did, insulating from the top, above an existing room-in-the-roof (R-in-R) is deemed to comply despite a higher (lesser) U value than the Part L target (this came in as part of the 2010 Regs). The thinking is that if you only have the rafter depth to deal with then rafter depth minus vent gap must equal insulation depth. Until 2022 ('21?) when the BEIS Best Practice Guidance docs came out this led to a typical set-up of 25mm vent gap plus 50 PIR (estimated U value approx 0.45ish). Now (as the BP doc requires 50mm vent gap) you'd only get 25mm PIR. An interesting quirk is that if you subsequently take the ceilings down in the R-in-R you now have to install a total of 150 PIR and achieve a U value of 0.16! And how do you tell if the 'from above' installation was done well? When you take the ceilings down, if all the insulation is on the floor, it wasn't! (Been there; seen that!)

Can we have a plan or a sketch? From what you have said I *could* envisage that the current width of your gate is the maximum width of entrance you could possibly have, in which case - since you already foresee them - I think you may have problems. But I don't *know*. You say 'may have to drive over my neighbour's land'. Does your neighbour know that yet? If you think there is any possibility whatsoever of trucks etc putting one little bit of a tyre on the neighbour's land you surely need to sort this first with an agreement (preferably 'for the duration of works, not a fixed term), not try to calm troubled waters later. Show us what it looks like and we'll think.

It would be good if they'd talk to you, but if they won't it sounds like a CLOPUD (Certificate of the Lawfulness of a Proposed Use or Development) might be needed. It's an application (cannot remember the price - I think it was half that of a Planning App when I applied last) to confirm that your proposals constitute Permitted Development. Alternatively a Pre-Planning Enquiry (Chargeable) might work, but if they are already refusing to talk to you it might not.

I am, perhaps, biased, but I have never seen the sense in using, in wet areas, boards which turn into weetabix if moisture gets in. I get it that (theoretically) the laminates are waterproof and so is the glue, but all the 'gone-wrong' examples I have seen suggest that things can 'go wrong. Even waterproof chipboard is only as waterproof as the glue and real-life examples show that water can get in and does 'blow' the board. My vote goes for something joiner-made from 'proper' (even if only soft-) wood. My kitchen is an example. The chipboard became unusable so we had softwood frames made, used the original softwood doors and found an oak tree for the worktops (OK, that was not cheap).

Splendid! And so simple!

Good job you showed us the box. The S7 and S8 I know would have had a right job getting up the stairs. https://en.wikipedia.org/wiki/Sunbeam_S7_and_S8#:~:text=The Sunbeam S7 and S8,to that of a car.

https://shop.smithsofthedean.co.uk/recycled-1520-litre--330-gallon-water-tank-751-p.asp See dimensions - you'll have 15mm to keep the right side of the regs!! (But yo do have to 'pass' a percolation test)

Given the site restrictions it's the overflow which worries me. IIRC soakaways (if your ground is suitable to Soak Away anyway) need to be 5m from buildings and 2.5m from boundaries. That suggests a max dia of soakaway of 1115 if I have read the dwg properly. If you can get them now, how about one of the 1400 ltr(?) cylindrical recycled containers (which used to hold fruit juice concentrate) peppered with holes? I have not seen them on sale in a long time. You can see them in use (above and below ground) at CAT.

Maybe, unless the plaster has been contaminated by hygroscopic salts pulled from the brickwork, in which case based on my understanding (limited, t.b.h) and experience (many many 19th C houses) is that the more that plaster pulls salts through the more likely it is to do so in future. I guess if you managed to make the wall as dry as a bone then there's nothing to pull, but I might be (nay, *would* be) tempted to hack out and replace that plaster (and a bit around it,) at the same time examining the brickwork for any 'symptoms' (whatever they might be).

@peekay, I have a somewhat newer cork-tiled floor, though still probably nearly 20 years old. I am not sure I have ever re-varnished it. I will post a picture later.

As ever I shall deal with the easy ones first: Move the loft hatch: Sorted. You also said: ...which is good. However you have a chimney breast in the way. Why not run the ducts above the ceiling in the void (*very well-insulated*, of course) and, with some 45 degree bends you can dodge round the ch. breast: Sorted (??) Very sensible plan. I don't have a better idea than that.

Is the top metal rail perchance by that nail-plate? In which case could the moisture be where the rail bkt has (*if it has*) perforated the membrane? Of course whatever flashing detail was used should prevent this but it looks like you have a point of entry and then it's running down (or not; I may be wrong!).

Our bathroom floor is looking a bit tired approx 35 years after laying, and having been re-varnished twice at most (perhaps only once!). It is still perfectly serviceable; just looks a bit ratty. These are bog-standard Wickes cork tiles c 5mm thick and approx 300 square. I intend to take them up and replace with... cork tiles.

Glad you said this, @Russell griffiths. It's the first thing I thought of, which avoids loads of complication AFAICS, but I wondered what I was missing. Am I right, however, in remembering that Durgo valves have to be inside?

Do they have to be sliding sashes or would inward-opening mock sashes do? Do they need to be 'scrape-through-the-Regs' double-glazed or 'Fully Monty' triple?

Re air-tightness, ultimately everything wants to connect to everything else! So if the internal plaster is the A/T layer, floor membranes want to connect and be taped. Ditto windows. Have you got your ground-1st floor detail sorted.? Search for 'Tony trays' if not.

Re the roof, yes, go for more. 120 is very borderline. I would put more in a refurb roof. Are you building the roof or others? The thicker the insulation the harder it is to find the timbers with your HUGE screws! I have seen a warm roof where most of the fixings were to the under-layer of 18mm OSB, not to the timbers.

Assume this is a neighbour? Was PP granted or was it PD? It's a while since I looked at PD. https://assets.publishing.service.gov.uk/media/5d77afc8e5274a27cdb2c9e9/190910_Tech_Guide_for_publishing.pdf Some enlightenment on p.12.

Easiest 'application route' is via a Building Notice. Look up your LA BC dept and search Building Notice. It's basically a fee and a pro forma which says 'I'm about to do this. (Strictly!) I will be starting in no less than 2 days, and you can come and look'. That's it. I don't know the fee for elecs but in my LA at least they 'buy in' a suitably-qualified person from 'outside', so you'll probably pay commercial testing rates plus a mark-up, I guess.

Care to share the maker?

+1. Can you post pictures so we can see the roof oversail (or not) etc? If you decide EWI is a no-go: I do wonder if trying to get a solution for the *whole house* using your existing plasterboard and frames might be blocking you from doing a high-quality wood-fibre or cork and lime plaster IWI solution to, say, 2 key rooms as part of an x-year 'rolling programme'.

Usually double-up the rafters either side and trim across as required, but don't take my word for it! Ask your BCO. I have seen 'standard requirements' vary from place to place.