Conor

No, it's standard, exceeds BC, and I didn't think about it.

We've 70mm metal studs, standard boards and 50mm isover accoustic roll inbetween... Can't hear a thing through them. Keep it simple, keep it standard.

What thickness screed have you allowed for? If its 100mm, you can easily get away with 50mm insualtion then 50mm liquid screed. I wouldn't even consider your other two options, you can just for the UFH directly to the floor I'd there's no room for insualtion.

As above, as the rise is more than 600mm, you need handrail, and ballustrading at the side to protect against falls, mum 900mm high.) As it's 2m wide, you will technically need handrail on both sides.... But here I think your BCO could show some compassion and leeway. I'd go for a metal free standing structure and just remove it after singoff if it really bothers you. Why is the floor level difference 700mm? Your architect really should have known better. Is there an option to add more screed to the lower level? I'm guessing an onsite change / error And if that last step is less than 150mm rise, could be an issue as well.

If its a case of what had been built does not match the submitted drawings, then it might be a matter of just providing these. Happens all the time, things change, can't put a pipe where you intended. While the work was passed as being "fine", the paper work needs to reflect what was built. That was the issue we had.

Oops

Everything since the date of the granting of your planning permission, as long as it's permenantly part of the build. Includes things like cans of expanding foam, sand, stones for access road, hazard tape for above your water supply. We just got our vat claim approved. I had in pipe welding solvent, decking boards (even though not on the plans), fence posts, shelf brackets (I noted these as forming a built in unit for plant), paint, bathroom vanity units, pretty much everything. Only item not approved was our staircase invoice as it specifically mentioned "design" as a line item and was rejected. I just need a split invoice (or one just with the total antld not itemised) from the company to claim. Just make sure all your receipts and invoices have your name and the site address on it. You CANNOT claim any vat back on items your build has bought in their name. Same for services

If it's to house a water pipe, I'd use 25mm blue MDPE.

2mm white foamy stuff. Don't go any thicker.

You can do it in 125mm and end with a 90bend and fit a Lindab airy valve directly to it.

Bare in mind you won't be able to reclaim any vat that the builder has incorrectly charged you. You'll need to go back to them and reissue invoices and something like a credit note that can be balanced off your next payments to them. If buying materials yourself, make sure the invoices / receipts have your name and the site address on them.

1 in 60 is fine on paper but if you are slightly off when laying the pipes then you've hardly any margin for error. I'd be decreasing the cover on your pipes where they leave the house to get you the little bit more fall. You can have the pipes come though the wall at any depth really, just need sufficient build over the pipe.

Probably render board with a thin coat render on it. Might even be some sort of heavily textured coating.

Inspection chamber at both and run A in to B then single run to the treatment plant.

We had exactly the same scenario. I fixed a 6x2" to the side of the slab using 180mm concrete screws, then fixed another on top with just woodscrews. A bit of ply on the face to act as shuttering for the screed. No issues and job done in an hour. The plasterboard fitted to the edge and then shoe rail for the ballustrading.

tbh, you'd be aiming for 10% TOTAL professional fees for a project like this. Typically 5% architect, 1-2% SE, 1% approvals, BC, PP and the rest other surveys and licences. The capital cost of the works doesn't really change this ratio much. All you can really do at this point is go to the market and get two other quotes. Don't rush in to anything.

No, it's only if they have been used as load bearing - as they can't really be used as structural elements (so said my architect and SE when I wanted to do our basement walls from reclaimed bricks).

We got a payment form HMRC today. No warning, just arrived in our account. Submission end of September. They have not paid ~£600, no idea what for but I suppose we'll eventually find out when something arrives in the post?!

Terrible brick / block work and somebody has tried to fill in the gaps with expanding foam. Worst chimney stack I've ever seen. Context? Own / buying / viewing? How old is it and is that an external wall or a party wall? If that is indicative of the quality of the rest of the work in the build, I'd run a mile.

After spending half the weekend painting our balcony steels with two coats of bitimous paint, I'd stick my hand in my pocket every time and get them galvanised. The stuff is horrible. I've even left stains on the bath FFS.

Lots of different banks have different rules. Some want a fully backed warranty, others a architects certificate, others nothing. Virgin and BOI didn't ask for anything. And a big chunk of others don't ask for anything after 2 years after completion. Just bear that in mind before forking out several £k.

Depends on your ground conditions, how your extension will or won't tie in to the existing, and the whims of your building control officer. If you have an SE involved in your project, then they can advise. And it will be difficult for the BCO to argue against a spec that had been designed and signed off by an SE. A trial pit is really useful.

I'm with @JohnMo. we run ours just fully manually using the room stat timer. If you do get condensation, it'll be minimal, limited to exposed pipes and gone again within a couple of house after the system turning off. You'll only be using it when it's warm!!! we had condensation when flow temp was set to 12c, at 14c there was nothing keep it simple, use your energy and time for something else.

In that case you'd use a rainscreen design. Battens fitted with 150mm galvanised screws, cement board to the battens, then your slips. Obviously a bigger cost, but has other advantages (don't quote me, vague memory from reading a passive house + article about the rainscreen design being preferred option for EWI structures.)

How my windows is that? We used internorm which seem to be on par with likes of Rationel etc but a lot cheaper.