Temp

So no Building Control involvement?

So do we. All our internal walls are block but they sit on full foundations like the exterior walls but narrower. Do you have a chimney and what does the foundation for that look like?

I think you need SE input on this, mainly to ensure the roof isn't going to sag and push the walls out. I recall reading that collar ties aren't intended to stop the rafters pushing outwards and that a structural ridge beam should be used if you can't otherwise triangulate the roof.

Email doesn't say if its a horizontal or vertical mullion. Better ask if not obvious. Probably full width or height accordingly.

Yes I think that's got to be discussed with the SE. He might suggest extending that beam to the cavity wall on left of the porch if that works.

That aerogel has a thermal conductivity of 0.015 W/mk compared to 0.023 for PIR boards or PU spray foam insulation (lower number is better). So 65mm of aerogel space blanket is about the same as 100mm or PIR/PU foam... 100mm *15/23 = 65mm

It would also be worth checking the return temperature to the boiler and the condition of any bypass in the system.

Check the pump is working correctly and that the system is correctly balanced first.

Any decent glass shop can make custom glass "shower" screens. In my area i'd recommend Go Glass in Cambridge. They should be able to offer a range of thickness (eg 8 or 10mm) and low iron Optiwhite glass that doesn't have such a strong green tint on the edges. Also different mounting options. Most places will work to a ply template but if any dimensions are super critical (eg it's going floor to ceiling or between two fixed objects) then perhaps ask if they can make the template.

You could try proposing a size to the BCO and see what he says. He might recognise it as being reasonable or he might ask for you to justify the size, in which case you would need calculations done.

This has to have been done lots of times. Google found... https://www.diynot.com/diy/threads/double-garage-lintel-spec.151818/

Welcome to the forum.

Typically you measure the opening and subtract 10mm (5mm each side and top and bottom) to allow for manufacturing tolerances. But the issue isn't a manufacturing tolerance issue but a spec issue. In no way can 46 x 110 be said to "match" 59 x 127. When you have one window above another, as you do here, the Architecturally "right" thing would normally be to match the width. The height normally being less critical. Its common to have higher ceilings and windows on some floors ... If the windows are side by side then the height would normally be the thing to match. PS no thats not my house.

You can probably get enough for £5.

could you lift the osb and move the sound insulation if its just one spot?

No it won't. Aside: concrete will need levelling even if what's underneath is level. Make sure you know how to do that and have people to help when concrete delivered.

The hardcore/infill should be compressed with something like a walker plate. I also compresses the sand. Are you sure the BCO wasn't referring to the overall height? Eg he thinks there isn't enough height left for whats going on top for the planed FFL?

I think it will be fine but I'd put a DPC between the blocks and osb.

Is that with you or them providing the digger?

We have a lot of oak outside, some treated some not. Untreated oak (eg padock gates) went black before taking many years to go silver with green litchen spots.

Don't you just hate it when you turn the TV on and someone has left it on the news channel and the first words you hear are "Hamilton/Botas has won the xyz GP......". Why can't that start with "and in motoring news..."? At least that would give me time to turn my ears off.

On solid clay with no ditches there aren't many options. If there is no convenient ditch you might propose a storm surge buffering tank/crate system with discharge into the foul water. A soakaway mound (or storm surge buffering tank and soakaway mound) might work if there is some surface permeability, but they can need a large area ideally down hill from the house. You can try not collecting rainwater and design the roof so water shoots off away from the house all around. After all before you build the house rainwater will just be spread on the ground. I think in some countries shooting water off the roof into large soakaways all the way around a house are used. Think the UK rules specify they must be a minimum distance away.

My understanding is that its very rare for there to be an actual breach of the right to light rules. https://www.irbnet.de/daten/iconda/CIB16863.pdf That suggests to be that a breech would occur if the development caused more than half of the room to have less than 1 lumen of light.

I would wait and see. Don't rush to change it. There are conservatories and there are conservatories. Does their conservatory meet the building regs as a habitable room (allowing removal of the door between it and the living room)? or should/have they retained the door? If its not considered habitable then you might point out its not a habitable room just a greenhouse.

Stone cills/polished marble like are popular in Europe. Even available in some European DIY sheds.