Mr Punter

By the time someone has broken through toughened laminated glass they will have made a terrific amount of noise. I recently had to assist a neighbour gain forced entry through a triple glazed window by breaking it. Took a while and was quite a racket.

I cannot see why this would not be acceptable a little larger. Make the floors the same size and get rid of the step in the roof and the kink in the flank walls. It will be simpler and better thermally. I would make the footprint 400mm shallower and 400mm wider and have a normal pitched roof. It will help mitigate the increased ridge height. Don't sink it down to the extent that you may have drainage / damp / flood issues.

British Standard BS8621 Dead Locks have a thumb turn. If you are not replacing the door or the lock I don't see why it would apply to you. The front doors we fit on new build either have thumb turn or just door handle to open. It is also an NHBC requirement.

A friend of mine does access control including automatic gates. He likes to use FAAC gear for the gates and Videx for the intercoms. There is a lot to go wrong and a lot of rubbish out there and he does not want callbacks.

The stairs do look very good. Could you figure where the wires could go to make them acceptable? They may have been better under the on the inner face of the string on the left hand side as you go up.

I think you need to approach the manufacturer and installer. Something is not right.

I like 2 x 1 battens fixed with long screws and plugs through 60mm PIR insulation. Finish with 15mm plasterboard. Gives a service void for cables pipes and sockets. Either foil tape the joins or cover with polythene.

That gives you 1 in 50 which should be OK.

A bit like buying a printer cheap and getting shafted on the toner. LPG is massively expensive. We once had LPG and it was cheaper to switch the heating off and go out to the pub.

Sewer pipe is smooth plastic with no obstructions and laid to a consistent fall on a firm bed of shingle. Flat roof are built with timber joists and OSB sheets, which can twist and sag, supported on walls that can settle, with complicated junctions, upstands, verges and outlets. Often there are trims or leadwork added at the point where the water should run off. There are a couple of flat roof puddle threads on this site at the moment.

The point is that people change flooring throughout the life of a building and on the bottom step 13mm will not matter. A thick carpet and underlay or some wood flooring can be over 20mm. All you will do is piss off the builder.

Make sure you have firrings to give a fall of at least 1:40. Not much will bond to expanding foam, but as the gap is only 12mm it won't matter. Dress the vapour barrier up the parapet a bit.

On an early project I bought a bungalow with consent to replace with 3 houses. A friend and I stripped out all the timber. We got someone to strip the roof tiles free. They were only concrete plain tiles so I am not sure why they bothered. We burned all the timber in the garden. The trick was to get the fire burning very hot. Not acceptable now, so I guess it just goes to landfill.

10mm is normally tolerated but they are very unlikely to pick up on this. It is better on the bottom riser than, say, mid flight. If you were to carpet the stairs and have vinyl on the bottom landing there would be no difference in rise anyway.

It makes little difference where you are if you are in England the building regs are the same. Maybe get quotes from people based somewhere less affluent, although I am not sure where that would be. Mansfield, County Durham?

The upstand is fair enough. Neither GRP or felt look very good. As per @SteamyTea I would have thought felt on top of the GRP. I assume you re the GRP and your neighbour is the felt?

@kxi and @Dreadnaught I have bought the Illbruck Compriband TP600 external sealing tape on ebay in the past at a very competitive rate. Keep it in the fridge before you apply it. I found it easiest to do after the windows were in. I have never used the internal stuff, just TP600 as external seal, squirty foam inside and polythene VCL to lap. I guess the inside stuff is to stick to the frame and VCL?

Steel rebar has fallen around 18% from the peak in May 2021. I think there is some profiteering going on over here!

Build up from the footings in blockwork, then swap to York Stone as soon as it will be visible (if it is suitable for below DPC). I think it will look better. Lap the floor DPM up and onto the DPC.

Privet can work well. If you are looking at Eleagnus, consider Elaeagnus × ebbingei 'Gilt Edge'. It is lighter and is variegated.

As per manufacturer spec. Often 2 fixings per tile for vertical.

M10 bolts are fine for connecting the timber to the beam. If you use the universal / adjustable hangers you can face fix or wrap over to set the joists at the level you want. https://www.strongtie.co.uk/products/detail/joist-hanger-with-adjustable-height-strap/769

You can hire a Hilti gun and shot fire the timber to the steel.

I have to agree that having neighbours, relatives and passers-by pissing in your ear while you are spending a shedload on a complex building project is enough to push most people to their limit. Put them on ignore. Hopefully this is the dark hour before the dawn.

You will need a lot of very long drywall screws to fix your plasterboard. I don't envy the tackers.