Redbeard

I misunderstood initially (I think). I thought you were going to retire to the bungalow and rent out your house. I now read it and think it's the other way round. I realise bungalows are a bit like hens' teeth, but do you think there is a good market for a tiny bungalow?

37m2? Back in my housing management days 35m2 was a '1B 1P' - one (single) bedroom, 1 person and really tight. Do you have drawings?

It depends to a degree on how well-ventilated the disused flue is. It should be really well ventilated ideally, but in some circumstances the 'in' (at the bottom) will be from the inside of the house (an air-brick in the ch brst in a room), not from outside. Which is the case here? If the air feed is from outside and the discharge is via the top of the stack then I am not sure you have much to worry about re condensation. If the air feed is from inside a room then you may have something to worry about, as the 'feed' is of warm moist air, not cold drier air. The warm moist air can reasonably be expected to condense out in the upper reaches of the flue. Other protection I would argue is less necessary since you will have a padstone below, and arguably a small lintel above. You could put in physical protection at the sides, but I would prefer, say, slate rather than (potentially sweaty) plastic. (OTOH it probably won't be sweaty if the cross-ventilating air is dry enough, as above).

I usually seal the wall with a lime parge coat. Although it is often not done this is quite important if using PIR (I wouldn't, usually), as the condensation risk assessments you get from the PIR manuf'rs will usually assume very good breathability *outwards* through the wall, on account of having closed the breathability path off completely with 2 sheets of foil. If the existing plaster is lime-based you may get away with leaving it, and augmenting where it never was (often behind skirtings, for example, and between Ground and 1st floors). Just make sure to strip off any non-breathable coatings. I tended to use wood-fibre a lot more than PIR. Yes, it is expensive, but much better at 'managing' moisture from the room. Even if you decide to use PIR I would strongly recommend using PIR *and plasterboard*, but not bonded. Yes, each sheet of insulated plasterboard has a VCL, and when you join them together, they don't! If you use separate PIR (or other insulation) and VCL you can tape the life out of the PIR before adding the plasterboard. Yes, wood fibre is only about half the insulation value of PIR but is so much better in many ways. And it does not give off cyanide when it burns.

Flashband or similar are good 'quick fixes'. They degrade fairly quickly, though TBF the last bit I used is still surviving in a 'second-hand' sort of way. The lead or alu could be 'permanent' (theft excluded!)

I am definitely not an expert, but HSE is/are, and IIRC some of the bitumen-based adhesives had asbestos fibres in 😞 I assume you have already read HSE's Asbestos Essentials guidance. This is the one you want: https://www.hse.gov.uk/pubns/guidance/a23.pdf

As possible alternative to lead you could possibly get a good alu fabricator to fold you a cover in self-coloured anodised alu. Lead needs a good lead-worker; Folded alu needs a good folder *and* good measurements to start.

Lead, but do you think it's porous? If that were a cill I would not be expecting to have to clad it. What is the specific issue? (Sorry, perhaps have not read the 'that leak' thread closely enough).

Yes: https://assets.publishing.service.gov.uk/media/61d727d18fa8f50594b59305/retrofit-room-in-roof-insulation-best-practice.pdf Proctors used to do (may still do?) a membrane which claimed to function with no air gap. I have sadly seen numerous examples where serious condensation and mould have occurred with a nominal 25mm air gap (OK, so poor installation and possible insufficient size of eaves vents may also have been contributing factors. For 25mm extra loss of headroom I honestly no longer think it is worth the risk. If headroom is a particular issue on stairs (re BR req'ts) consider sacrificing 25mm of insulation in that area only.

Sounds like foil-backed plasterboard, the foil being a Vapour Control layer/barrier). On the other hand I have never liked it since, at every joint, there isn't a VCL. Is that picky? Especially nowadays when many use the VCL as the air-tight layer, I don't think so. and So if you can afford to lose internal space how about remove the plasterboard, 75 x 50 timbers horizontally at 400-ish ctrs (to suit insulation size), Yes, you still have a full-depth thermal bridge at the cross-overs, but life is not perfect. Either that or go over with some rigid board, such as PIR (I dislike it as much as many), taping all joints and perimeters as you go, and then 25 or 38mm deep battens screwed thro' to the frame and there's your VCL and service void. (and if you take the view that a hole in the VCL for the screw is a hole in the VCL, pre-drill, squirt in silicone and wind the screw through its own 'silicone grommet'. Or can you do EWI? For Best practice you'd still have to address the incomplete VCL but if it is done well it can be a very good thermal overcoat. Out of interest has your frame survived with little rot?

Sorry, I've been trying to find 'Fred Drift''s comment. @ProDave, are you using voice activated posting?! Sorry again!

Doesn't sound right to me, but try the manuf'r. Importantly, AFAIK, it is not a vapor control layer. It is a waterproof membrane which is capable of 'breathing' *out*.

Much as I like to advise getting the heat-loss down as low as possible before considering a HP it is not true that they won't work in a poorly-insulated property, but they may cost a fortune to run, or simply even not be big enough (most single-phase HPs max out at 16kW). Depends a lot on the size of your house. Depending on the current flow temp of your boiler (some old houses run at 60 - 70C) you may need to increase the size of some or all rads. There are high-temp HPs but I am not at all sure of the CoPs (Co-efficient of performance - kWh of heat out for each kWh of elec to run the HP) they offer. You are right also that an over-sized pump (as you improve the fabric performance) could be an issue, though others will know more than I do about HP modulation - effectively the ability to 'behave' like a smaller 'boiler' and not shorten its own life by short-cycling a lot. A buffer tank may be recommended too I am not sure that unless you either have a **huge** array of solar and batteries or need a lot of heat in the summer. By all means note that if you have a HP a sunny day may offer a little bit of help to it, but I would not be expecting much. Lots of advice on here already re internal insulation and what is best for old stone buildings. Does your house have a high degree of exposure?

Assume min 60 yr life required, so not corrugated bitumen board, in my experience (although poorly-supported bitumen boards 'go' a lot quicker). I took off some (?pre WW2?) corrugated in about 2015 and yes, it was 'chewy' at the edges, but (a) so much thicker than modern, (b) still with most of its galvanising on and (c) solid as a rock at all but the edges. Self-coloured, of course. Epoxy if you can. Layers I could guess, but I'd be guessing, so I will leave that to others. Battens and counter-battens will be involved, I suspect.

What you need to stop is the tamped under-layer 'extruding' out and causing the paving to drop. I don't think loose anything will help that much. What I had in mind was to cut away small areas at a time of the cut-down haunching and back-fill with concrete to the 'point of the triangle', with that infill going below the level of the tamped under-layer to form a 'footing'. Then run a sloped area of concrete from the same level as the 'footing' up to the bottom of the cut-down haunching. If I have misunderstood, and there is something solid holding up the under-layer which I think I can see exposed (and thus unsupported) , please correct me.

Get a structural engineer to do sketches and calcs. BCO always took SE's calcs as 'Gospel' in my experience.

Hello. I suspect you need to excavate so that the haunching has a footing, then at very least make sure your new, lower haunching physically connects with the existing 'mini-haunch'. I think I would under-cut the 'mini-haunch' slightly.

Agreed, to some extent, but the aim is to eliminate unintentional ventilation and replace it with intentional, even if there's a bit of overlap as the 'unintentional' is being designed out. Thanks @JohnMo. I had looked at those, but since they 'will open and close based on humidity...' and the 'air in' will be in one room with the fan 'out' in a wetter room it may depend on how good the inlet units are at their job. In a less-than-ideal situation the humidity could reduce in the 'inlet' room, making the inlet vent close. However the dMEV fan is running permanently (albeit at only 1-2W) and pulling against a closed inlet. As @gravelld suggests, at the 'start of things' the dMEV fan will just pull in air via 'unintentional' routes, but when these are all closed...? I suspect the Glidevale unit may be fine, but any comments on my 'scenario' gratefully received.

dMEV usually functions with a window trickle vent as the 'inlet' part. Some of these are baffled which helps to reduce excessive ('unwanted') ventilation. Due to the window design a window vent is not possible. There simply is not enough 'meat' on the frame. I am trying to source a baffled wall vent to use as the 'in' part of a dMEV installation (probably a Greenwood CV2) but am really reluctant to use a bog-standard air-brick which is not baffled at all. Does anyone have any ideas as to what I might use? Thanks.

Was the installer HETAS registered? If not, who signed off for Bldg Regs? If installer is HETAS reg'd may be worth asking HETAS if they have a minimum standard for making good. ('Not leaking' would be part of it if I wrote one!). Of course HETAS is (I guess) more about combustion safety than roof-work, but they are very closely linked - i.e. part of the same job. I would also get a quote for making good properly and inform the installer that this is what it will cost them.

FENSA is a Self-Assessment body, in the same way as HETAS and certain elec bodies for their areas of expertise. If you don't use FENSA (AFAIK there is not another windows SA scheme) you (or your contractor if you have one) have to apply (and pay) for B Regs approval. I nearly always do that via a Bldg Notice. Around £200 when I last did it. May be more now, and prices vary a bit between authorities anyway. If you do all the installation work yourself be sure you are happy with assuming the Principal Designer and Principal Contractor roles yourself (shouldn't be an issue with windows but may be for more involved work. Still *could* be for complicated window installs, I guess.) Given the passage of time S & F for £850 sounds not so far from my c£735/m2 supply only in 2022 for another high-spec 3G supplier.

Agree with Compacfoam, and definitely at the bottom too. I think we used 75mm. Consider removing some masonry if you have already built up.

It certainly isn't invisible, but I have seen far worse. My worry is that they have apparently chosen to site the joint well on your neighbour's side, so that if (as the neighbour seems to forecast) it does leak, your neighbour 'gets it'. Obviously not a great strategy for good neighbourly relations. Since the scaff has come down you are a little stumped in the short term. Long-term bargaining point could be for the roofer to return, make a tidier job of the joint (to your neighbour's satisfaction in particular) and make the joint on the boundary. Of course we cannot see the main joint behind and on the other elevation.

Unless the son is doing the work entirely financially unrewarded there is an argument that a contract exists. If that is the case then, unless his insurer precludes work for family members, his insurance is probably valid for the work - if he has any. Don't worry much about him being a 'sole trader' as opposed to ltd co. Many, including me, have no wish to be more than a sole trader, and it's a perfectly acceptable business model if you don't feel the need to limit liability.

Possibly XPS-insulated tiling board. Seems to have reinforced (?)GRP on each side, made to take internal plaster, which would therefore happily take render. XPS is used outside in below-ground EWI (whether it needs to be or not - discuss - in another thread!) so no problem in this location. Sorted (?). Even better, just checked for vendor - Jackoboard is one, and they do varying thicknesses. Whooppee! Seems made for your job.