Redbeard

Definitely not in the roof unless it is insulated at rafter level. Performing heat exchange in the coldest part of a house is not a good plan. You *could* construct an 'MVHR Shed' - a highly-insulated box for the MVHR unit to sit in inside an otherwise cold loft. Agree with @JohnMo that if you have much over 3 m3/m2/hr (or air-changes per hour - sometimes the scales converge and sometimes they don't - depends on the form factor) MVHR is a very expensive way of ventilating. OTOH I do know of people who have still gone ahead on air-quality grounds for specific health reasons.

No - sorry, but I have done a TF extension clad in WF EWI and rendered. BC (particularly under the 'new' (ish) regs) got a little concerned about 'surface spread of flame' and then decided that since (in my construction) there was no surface effectively exposed to flame - unless the whole sandwich' were already on fire - they had no concerns about surface spread of flame. In your set-up you do not mention a scratch-coat of render before the (cavity and) cladding, so you have, from outside, timber cladding, 50??mm gap, wood-fibre, timber frame. I assume the cavity is formed with 50mm sq battens. So it's all wood. In the past there used to be such details (the late NBT used to have one for a set-up like yours, but under the latest Regs/Bldg Safety Act/Post-Grenfell caution 'regime' I can understand BC asking 'for more'. By the way, what centres would your horizontal barriers go at, and do they not stop it being a ventilated cavity. I may have misunderstood. If I have, the cavity *is* ventilated, but somehow has barriers which would stop fire. I am aware I may be being stupid! Can you dis-confuse me? (Aside of that, how about you propose to BC that you do a coat or 3 of lime render on the WF EWI before affixing your battens (/?barriers?) and cladding, as a fire-stop?)

Hello, Why is the Intello to only come 'up to 400 above the joists'? If you continue it all the way from one side to the other, and do all the details correctly then there is your answer to I have not used Solitex Plus before, so I assume you know (as I don't) that it is deemed OK by the manufacturers for venting *above* rather than *under* the membrane? I would have vented below the membrane, but that's just because I am a 'dinosaur'. You say you but your counter-battens assure that it will not look as it currently looks, surely? I see why you want to vent above the membrane, to keep the 'lay-up' thinner, but if that's at the expense of upsetting the conservation officer then it doesn't achieve much. Have you agreed the roof rise with the CO? Your reference to penetrations and integrity of the a/t layer suggests that you already know it will be a PITA to to all the cutting, priming and taping. It is, though, exactly what I would do. Taking it down into the room below could leave an unsightly 'blurge' of A/T tape at the top of the room, but if you chop out the plaster at the top of the wall you could (a) before the taping of the membrane round the joists, put a thin (say 6-10mm) coat of lime plaster on all the brickwork then, when it has gone off, prime it and tape the membrane onto it with one of the 'plaster-onto' tapes. Then do just that to finish.

I think I have got their first album. And on a more serious note, I saw some thin-film amorphous silicone panels hanging outside a flat recently. Possibly some Qs re safety (and of course I do not know whether that was a low-voltage or an inverted 'system', but the extremely low prices of PV now make it tempting. I wonder how long it will be before Planning implications are brought up? Will all such uses, for example, be PD? (A quick think says probably yes, but there are exemptions for some 'sensitive' areas.

Depends where you live and how high the rain splashes up. Bldg Regs assumes it will splash up 150mm. No-one told the rain where I live that it can only splash up that far, so it goes up to 300mm. 120 sounds unwise, and 80 much worse.

Does the GF WC exit into a vented soil stack?

I haven't - sorry - but what standard of air-tightness are you going for? The answer may answer your Q.

How will you ventilate the 'shed'? If you might want from 'just a trickle' to 'just a bit more than a trickle' put a small window in. You can't leave a bi-fold a little bit open and go out (AFAIK) with any degree of security. If you think you can build it yourself I would build it yourself. You will get what you want (or what you think you want as you start building, anyway), not just something 'not too far away' from that. Check out the insulation detailing and membranes etc. v carefully and build scrupulously tight. Some will disagree but I see SIPS as sometimes the wrong answer to the wrong question. You could consider building a frame and externally insulating and rendering it. All finished in one go.

+1 it needs an upstand. If the existing won't let itself be 'popped up' to achieve this I would make one. I did exactly this on my (OK, pitched-roof) shed 14-15 years ago, using mainly (ughh!) Flashband, and it is still fine. We used a triple-glazed unit which had been made to the wrong size.

You may know this already but PVC cable sheathing reacts with PS, so don't let them hug each other!

Hi. You say Is the wall in question rendered, or was that added as an extra variable? I would do 1 and 2 as you suggest, and add 2(a) remove render for approx 100mm diameter. Fill BIG gaps (should there be any, given a 'clean' hole?) with mortar. Allow to dry Prime area and pipe with air-tightness tape primer. Leave to dry tacky Apply one of the 'fluffy' a/t tapes designed to be plastered/rendered onto. (Pavafix Win or (?) Pro Clima Contega (?may have changed its name?). Lap the tape onto the pipe just a tiny bit less than the depth of the render. Apply render. Alternatively use an EPDM grommet but I have not yet refined the thought-process for ensuring that the EPDM square stays stuck to the wall. You'd still need 'fluff tape' over the EPDM anyway, so maybe this is a non-option. Your mention of render is not repeated in your 'steps', so I may have got the wrong end of the stick. Out of interest what do you mean by taping I am guessing: Bottom piece of tape Tape 2 above overlaps by say 15mm Tape 3 ditto Etc. That sort of thing?

To how far below wall-plate/threshold? I appreciate you will need level access at the door, but I am never happy with the 'standard' 150 to DPC (/wall-plate in this case). No-one told the rain where I live that it can only splash up 150mm, so it does its own thing and splashes up 300.

If you genuinely want uneven render on 'even' blocks you could tack expanded metal on with the odd spacer here and there, and apply the render more with rubber gloves than trowels.

Remember, if it is next to another susp. tim floor which you are *not* converting to concrete, to bed ventilation ducts under the (insulation under the) concrete floor.

Or you can turn it into an insulated solid floor (depends how fundamental your 'redo' is), and have none of the possible issues which can (sometimes) occur with insulated suspended floors even if you follow all the best practice guidance.

If low cost is of the essence then 'contract matt' (once used by volume builders, AIUI, to allow painting a bit 'too early' over plaster - perhaps less so now with taped joints) is probably the one to go for. As @SimonD said, avoid anything with Vinyl in the title (and I think, but don't have evidence to prove, that anything 'silk' may/will be less breathable.

Which is better than many (but not all!) built-up felt roofs, but my slate roof is 130+ years old. Yes, it has had repair, but none of it has had any more than patch replacement. I think the copper roof on my old school is probably 65+ years old.

My first thought was 'yes, you can, but you can also paint jelly'. Slightly more context, yes the jelly would be less successful, but I always fight shy of building in a maintenance liability if I can. Can you reduce potential splash-up by, say, a small gravel-filled trench (even if not a proper French drain), take the cladding down to 150 above GL (The bottom plank may be 'sacrificial' as I would normally say 300) and just rely on the fact that you might not spend too much time lying on the ground looking at the orange bricks?!

Yes, that's effectively the 'Tony Tray' that many on here have discussed. Arguably yes, though it won't be as perfect as a Tony Tray Which continuous top plate? Not sure I get this bit. Can you explain, perhaps with a felt-tip annotation?

Good Q: *Looks* (I think) like a woodburner flue, but as stated above, that should be at v least above the eaves, and quite possibly higher still to avoid downdraught.

Silly quip deleted!

I have no connection with them, but I was looking for an independent WUFI-wrangler recently, and Greengauge https://ggbec.co.uk were apparently helpful to the person I was helping.

I am a little confused. The normal suspended timber floor consists of boards of some description directly over wooden joists (175 x 50mm is a fairly typical size but they may be smaller if they are supported mid-span). You say your floor is planks *over floorboards*, and you refer to the possibility of taking up the planks. My first thought/Q is whether a decorative floor has been laid over the original. Is there a 20mm step in the doorway? Pics would be great. Also how do you define 'wonky'. Loose, or far from flat (or both?). Or something else? The more info you can give the more accurate and useful will be the replies.

1st obvious Q: Is the old house to be demolished?

Last and last-but-one pics - what will happen next?! The phrase 'hanging in the air like bricks don't' - with a little modification - comes to mind.