Mr Punter

Often have to put a bung in either end of the run. Sometimes with external runs you put a bung at the far end and fill the whole underground runs with water.

I have used https://www.roofingsuperstore.co.uk/product/dupont-tyvek-flexwrap-nf-152mm-x-23m.html around pipes and ducts and for under / a bit up the sides of windows. One roll should do the whole house.

For somewhere cheap - £200,000 - the tax is £1,500 For somewhere more expensive, say £600,000 it is £20,000. Perhaps roughly what each person may pay for a car or annual holidays. Not an unfair tax IMO.

I also don't get the forever house. What is the objective? Things change as you go through life. Moving is fairly cheap and if you are lucky enough to always move somewhere more suitable, why not? I spoke to an older couple today who have a fantastic large detached house on 1.5 acres but they are looking for a new house which is central, easy to heat, lock up and leave, no garden maintenance. What they had before suited them with young children, but now has become a bit of a pain, so time to move on.

I have used XPS insulation which has a much higher compressive strength than EPS and PIR type insulation. I have used it on a garage floor under plastic tiles. Fairly cheap. Stuff like Foamglass is perhaps stronger but costs loads.

40m2 is fine for a studio. I think the minimum to be mortgageable may be around 30m2. Normally work well in town / city centres or holiday lets, not burbs or rural.

Timber frame needs a drained and ventilated cavity. to do otherwise is a risk.

Where does the timber frame start? Looks like a fair amount of brick and block so far, so you may do better sticking with that. Maybe you could do timber frame kit for upper floor(s) and roof if you are keen on it. You may need to build solid below ground as this is retaining a reasonable amount. The small below ground bit makes this very awkward as you have extra issues with moisture, retaining soil and insulation bridging.

Get an engineer to look at this again. You could use piles, king posts or sheet piling, none of which require 2 metres.

What is the knapped flint all about? Is that a vernacular style where you are? If not, I would not bother as the panels are too skinny to look anything and the bond will be all over the place.

There does not seem to be any storage space. Also the bathrooms look tight and I can't work out where the landing is. What is the room top right? When you say 1 metre reduction in width, is that side-to-side or top-to-bottom on your plan?

I like that you can change the modules and have several intermediates on 1 switch plate, where nobody else seems to do, say, a 3 gang with 2 intermediates and a 2 way unless you go for a grid switch. Decent value too.

Alu clad uPVC is another option if the planners don't like uPVC. I think the timber colour looks a bit naff.

For warm flat roofs, 100% of the insulation should be located above the roof structure on top of the deck. In practice this does not always happen but you are best to follow the BBA certificate of the insulation manufacturer.

My experience with warn air heating is that it makes the air very dry, making ones eyes and skin feel itchy and uncomfortable. Also the air tends to form currents rather than be distributed evenly. If you could add humidity, this may be OK, otherwise you may want to replace with rads. ASHP will be expensive to run if you do not improve airtightness and insulation. Perhaps a combi boiler with rads is your best option. As you have identified, the solid concrete floor will be a pain to insulate as you probably don't have enough ceiling height to do this without breaking out the concrete, but even 30mm Celotex overlayed with chipboard will make a considerable difference. Blown bead cavity wall insulation is reasonably cheap and cost effective. I am not sure what, if any, insulation is in the first floor ceilings, but if none, this will be and area where you will lose a lot of heat. With the loft part you can just add more loft roll but with the sloped areas you would need to strip the plasterboard if you want to add insulation. All your Immediate items look doable with your budget and although a mile away from the standard of self build new builds it will be a great improvement on what you have.

Cutting in looks neat. Did you have chamber covers? If so, photo please so we can check...

No as it transfers the building loads to the ground underneath. I imagine there is a depth where this could be ignored but it would be very deep and you would likely need an engineer / soil survey etc. and a large safety factor.

You should be able to mount the indoor unit straight on to this as they don't weigh much. For the large hole, you could make a 75mm inspection hole behind the unit with a hole saw, and refit the plasterboard if you caught a stud.

That does not look like toughened glass as it would shatter into far smaller pieces with very few sharp edges.

I have seen some contractors replacing all the glass balustrades on a development near me. They were frameless and recently one of the panes failed, shattered into pieces and fell to the ground. It was only then that it became apparent that the glass should have been laminated as well as toughened so all the panels on the development were replaced. The failure had nothing to do with the weather.

We built a 4 storey terrace next to a river. We piled down 25m but the nearest we could safely install the piles to the river wall was 3m, so the engineer cantilevered the ground beams. Lots of reinforcing near the cantilever, but this was a much bigger engineering challenge. The rear of the houses is cantilevered about 2m and the flood wall a further metre.

If it is just concrete block demolish looks the most sensible way forward. I would not be keen on a "fingers crossed" approach when investing so much money. Get a properly designed solution.

But down the sides they just have soakers that between the slates so even if the window is set a bit high they should still work without kicking them up.

This is in Westminster. If there was a spare 200mm of land, I suspect it would have been built on.

Just go a thick mortar bed on the low spots and a tight bed on the high and you will do it in 1 course.