Redbeard

Not mine - @nod's, but the cost is per m2, irrespective of the no. of storeys. A smaller extension may have the highest cost/m2. A porch I did once certainly did! The 'mastertradesmen etc.' site seems to be a register (though I don't know how you get on it - didn't look that far). They have a number of plaudits from members on the site. I know nothing of its history or operation, I am afraid. I would value personal recommendations from local people above any number of web-sites, though even then you have to bear in mind that people will 'value' different elements of the service differently.

Re 1-3 (dot, dot and dot) above: 1. You and your designer. (In certain circs you may opt to get a Certificate of Lawfulness if you think the PD is too 'open to interpretation' (you say it is, Planners say it isn't!) in your case.) Cannot remember how long it took but the one that I have had to do (before online submissions) took about a tree's-worth of paper! 2. Yes, unless perchance your chosen builder has a preferred architect. This of course has advantages and disadvantages. If the architect is used to communicating with the builder directly and responding to 'dynamic issues' as they arise you could, potentially, find yourself with things you have not strictly agreed, however sensible they are. Even if it's the 'builder's architect' you would engage them. 3. Costs: Sorry, no idea. Others will have.

@steveoelliott, if you are in any doubt whatsoever perhaps try, via the contractor, to get another couple of clients who are prepared to talk directly to you about this contractor. May help to put your mind at rest. Is he a Ltd Co.? If so you could do some background research at least about the status of the company.

So sorry that you have had this ****. Did they say it in writing? If so, a written reply confirming that you will not pay sets out your stall. If they did not say it in writing still write to them with a statement confirming your belief that they agreed this on x date and have done/said nothing since to change the parameters. What does their contract say about payment terms and the status of the grant in the 'negotiations'?

I still have vivid memories of getting my cast-iron bath up our stairs (incl 2 winders) 38 years ago. I was younger then, and had 2 friends who were built like 'masonry toilets' (phrase amended for delicacy). One got underneath 'wearing' the bath like a turtle-shell, and the other one and I (definitely the weakest link) took the ends. I do not recommend this method, and I very much like G&J's idea, which could not have worked for us. The only circs in which a Genie lift might have helped would have been if we had removed the bathroom window - and we hadn't! Why ion earth did we choose a cast-iron bath? Because we had bought our replacement 'suite' from my preferred bathroom supplier, the local scrap dealer. He had plenty of plastic baths, which I wanted as much as a hole in the head,but I wanted a pressed steel one. They did not have pressed steel, but 'we've got this'... From the manual handling point of view, not one of my wisest choices! It's still in situ, though.

Make a feature of it with a step-down 'cascade' made of gutter off-cuts screwed to (a board screwed to) the wall, then it won't be 'in your face', but artistic.

I like drainage membranes better than I like trying to make tanking slurry work, but they can have their issues. Firstly, before lining-out consider 'closing' the top of the membrane. The training I went on with a supplier didn't suggest this, but I found that the % moisture content of some of my joist ends increased after the installation. External ground level was a little below the bottom of the GF joists, so for some of the area I was able to use primer and butyl tape to 'close the environment' behind the membrane, so that the only route would be down for mainly liquid water, not upward (towards vulnerable timbers) via the open top of the membrane. That's one issue, and another (formerly addressed by at least one system provider) is that failure to provide full vapour control around the full perimeter of the insulation can leads to condensation on the inner face of the membrane behind the insulation. If the wall membrane is taped to the floor membrane (again, as suggested by a number of system providers) there is a risk of a 'pond' that your board floor might sit in. The alternative suggested by the system provider was to run the wall membrane down below the floor membrane so that any moisture on the 'wrong' (inner) side of the membrane can at least escape into the perimeter drainage channels. But this in effect 'legitimises' interstitial condensation which is, at very least, a bit hard to get used to. Air-tightness here can be tricky to achieve. Floor is easy - VCL laid over the insulation - and that can join the foil on PIR or A.N. Other VCL, but a conventional VCL at ceiling level will be a VCL on the wrong ('cold') side of the insulation sandwich for the (GF) room. Installed where? Has the extension got a drainage membrane? Surely not? Can you clarify? Can you provide more detail please - words and drawings? More responses when I have a full understanding of the circumstances.

The moment you start doing retrofit a 'bit at a time' the un-done bits arguably become vulnerable. This should not be a cause for panic, but regular observation and risk management are your friend. I have differing U values throughout my house ('Incremental Retrofit', or need for a round Tuit). Not least, if you think about it, filling your loft with the 'approved amount' of quilt insulation will give you 0.16W/m2K. If the rest of the house is uninsulated elemental values could be as high as 5 (metal s/g wins) and fairly widely 1.5 - 1.7 (unfilled 50mm cavity and 225 solid brick respectively).

Yes, section dwgs wd be great. Could the post perhaps sit on compacfoam at btm and have a further chunk of said compacfoam at the top? If you know what 'look' you want, why not simply have the post made with the necessary 'tangs' to which to mount your cladding/expanded metal/what you will?

Does the fact that you have put 'boundary line' in inverted commas suggest that you have doubt about the boundary? The existence of a 'hard' 'boundary' in the form of the fence makes me wonder if the land under the hedge is classified as 'amenity land' - owned by you but with restrictions on use. Is that your driveway in the front of the picture?

'Decent U values' for a new extension may be very different from those for IWI'd solid walls. (All values which follow are W/m2K) I'd be looking at something like 0.12 for a timber frame wall. I got about 0.16 for my extension, about which I felt quite smug when I applied for B. Regs approval (when the target was 0.28), but less so when, within months, the new regs came out, requiring 0.18! So I guess I'd try to enclose/'wrap' the old building with the extension as much as possible. You may be looking at only about 0.5 - 0.6 for those insulated stone walls. For roofs of course you ought to be able to get down to 0.10 or even 0.08 - 0.09W/m2K whether the roof is old or new, but if you have sloping soffits you may be limited in terms of room height, and awkward choices ('unfriendly' insulation and really good ins. value vs 'Friendly' insulation and not-so-good U value) may have to be made. For the extension I'd do timber, just because I build in timber whenever I can. I taught a variation of the Segal Method for about 15 years and am pretty obsessed with it! Above everything it is Ridiculously Good Fun and very empowering.

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.