Mr Punter

Yes. A few others do similar. Celotex suspended theirs, which was a shame as theirs had a better interlock to prevent water ingress. Be aware that some u-value claims include for insulated plasterboard and lightweight blocks, neither of which are my favourite.

Full fill rigid (PIR type) insulation will meet the u-values and work out cost effective. Correct installation is critical, so you need to make sure your bricklayers follows the instructions to the letter.

Be very wary of the proximity of trees with the clay soil. Even if they are small, Building Control will expect you to calculate and design the foundation on the basis of their fully grown height.

Leave it to the designer to decide but I would think timber should be simpler, cheaper and easier to connect on the truss press. You can specify the max floor deflection if you have concerns about bounce.

If you want good acoustic insulation the dense mineral wool is better, if you want thermal the PIR wins. You could stick some Celotex - say 30mm to the wall then a 10mm gap and 70mm metal stud with 2 layers of 15mm soundblock infilled with dense mineral wool. I am not sure if this applies:

You may be overthinking this. Independent stud wall (95mm timber or 70mm metal) with the face of the studs 110mm from existing wall with dense mineral wool infill and 2 layers of 15mm soundblock and there will be no thermal or sound issues. The regs give you lots of leaway as it is an existing wall and not exposed to outside. Metal stud would be my preference.

What is the wall makeup for the party wall? Is it 2 x single 100mm skins with a 50mm cavity, a 215mm solid wall or what? What BC are suggesting does not sound outlandish.

Was it building control who said this? You are right, the gaps underneath the infill blocks will give adequate ventilation, especially if you are detached with air bricks all round.

CT1 has its uses but it is very difficult to get an average finish and the clear and white look piss yellow after a while.

Pull the black collar towards the bit.

As above, get a professional to look at this. You may need to apply for consent to have a condition removed or varied and you can use the professional's advice to establish that the proposal will lessen the impact and is in line with policy / local plan. Do it now as it will probably take 3 months to get a decision.

I have used low iron glass in some 25mm thick external balustrading without handrail and the difference in colour is noticeable, especially when looked at from the edges. It lets all the light through, so make sure you have decent solar control. Does it work OK with low e coatings?

Fantastic job. I really like to see quality craftsmanship and it seems so rare.

+1

Really? We have several different glass specs on the same elevation - double glazed, triple glazed, toughened, laminated, different gap widths and pane thicknesses and I have not noticed any difference.

If you used stainless they will only have a bit of surface rust and should not cause any problems once rendered.

The glass in a frameless Juliet balcony should be toughened and laminated. It is likely to be at least 12mm thick. The glass thickness and the location of the fixing points are the main factors concerning how much flex. Are you having a handrail on the stairs? I wouldn't want my mum trying to grab the top of a sheet of glass to steady herself after one too many drinkies.

If the timber is left a natural colour, the bits you have coated will weather differently, so coat the whole elevation or it may look crap.

As long as they are the same colour and general style (modern, traditional etc) they will look fine.

I have known BC to object to any FR coating that requires periodic re-coating, which was why the non-com stuff was oft specified. A right pain and vast cost. As per @Ian this is only an issue if you are near a boundary (not necessarily another building) and if that is the case you may be better choosing a fibre cement based cladding.

Very strange having a Pozi joist ground floor. How do you get access to fix the non-combustible board? Also, fitting 150mm rigid PIR insulation between Pozis is near impossible. Can you not do beam and block or concrete hollowcore instead?

The gaps are not very even but should be fine with mesh coat and the render will fill the gaps in any case. You could have used plastic packers. I would not fancy grinding a gap - sounds messy. If this is a "proper" expansion gap going through render and board with the special bead then he may have a point but I have done some fairly large walls without. I think horizontal expansion gaps are more important than vertical on timber frame, but you need a break in the vertical battens to match the expansion gap in the render. As yours is not multi storey I would not bother with any. For fixing I use stainless screws. They react less with other materials and were recommended by Bluclad and other board manufacturers.

Regarding the materials, if the rest of the house is brick, you could do the extension in render or vice versa. Regarding the windows, the CO makes a reasonable point and I do not think the rear elevation looks well resolved. It is hard to see where floor and ceiling levels are, but I would want a decent ceiling height in the kitchen and the new extension looks a bit squat.

The danger may be that the house has far less value when you come to sell. I rather liked the idea of tiles. The combination of timber cladding and green roof would be too much like a hippy shed for my liking.

Solving the dampness issue is best done with type C which involves stripping all internal linings. I can understand why the idea of a croft house conjures up romantic notions of renovating a beautiful old building but it will be lots of work and cost and you will end up with a poor layout and a substandard house compared to a well designed new one. If you find a plot and start from scratch you could build a lovely home that is sustainable, easy to heat, clean, dry, airy, light and with spaces that work for you. There are also far fewer unknown costs with new build.