ProDave

Is it this one? That is using a stone hearth, and metal sheets spaced off the wall for heat protection of the wall. That is something like you need to do. And twin wall flue all the way from the stove through the rood.

That would make my blood boil and be showing him the door. My parting comment would give me a best and final quote by post valid for at least 14 days and I will let you know.

That is OLD wiring probably 1960's. Conduit will be the earth, neutrals direct to lights looped light to light. Live direct to switches looped switch to switch and switched L from switch to light. The twisted connections are "Screwits" No idea what the extra cable added does. Honest opinion, your lights need rewiring, who know what the rest of the wiring is like.

I suspect the issue with concrete products is the energy needed to make concrete and rising energy costs.

You would only know that with a proper detailed heat loss room by room. This is the second house we have built, both with 200mm spaced UFH. The first one, 18 years ago was an "ordinary" timber framed house with 150mm insulation in the walls, 200mm under the floor and 300mm in the loft and there was no issue with cold rooms. Closer spacing does not create problems so no problem going closer just to be sure.

It remains to be seen what is going happen to energy prices. While many are indeed predicting electricity at 30p per kWh, a 50% increase on what I thought was already a stupid high price, the same people are predicting gas may go up 100% We have no control over this, but you DO have control over the house you build and it is becoming more and more important to get at least close to passive house standards when you have the chance at a major renovation or rebuild.

If you relied on a torque measurement, then a lot of the recent MK sockets I have had the misfortune to install the wires would fall out, because the screw is such a lousy fit in it's thread that it is all you can do to turn it at all. (you might gather I never fit MK by choice these days)

And what is "wrong" with 200mm pipe spacing? Care to post the design?

And my other, trying and failing to sell our old house in a depressed market, resulting in a "plan B" a 6 1/2 year very much more hands on "self build as you earn"

More of a concern to me as someone with only weak 2g phone signal at home, is will the 2g switch off mean they finally get their finger out and give is 4g coverage? Or will we be left with none?

Hi and welcome to the forum. Plenty with health issues self build though obviously not full hands on. You plan is good, your idea of budget sadly is not. £100K might get someone to build and erect a timber frame but that is a long way from being a habitable house. With the recent rise in materials cost allow £2000 per square metre for a finished house. The economics are not always in favour of a self build, it is more about getting the house that you want built how you want it. Going forward that should also mean very very well insulated and air tight etc so you get low running costs. Edinburgh is probably the most expensive part of Scotland, others will have to advise where you might find a sensibly priced plot within an hour. Start by looking at https://espc.com/

Re UFH in the original house. You have limited headroom and you NEED at least 100mm of insulation under the UFH so your only option is dig up the present uninsulated concrete slab, dig down further and re lay with proper insulation under it.

What you are seeing there is a woefully poor lack of design and lack of detail. the rafters are probably supported on the wall plate on the inner leaf of the wall, something is supporting them, they are not just levitating there. That is the least of your problems. The way the insulation is fitted, it might as well not be there. you need to ventilate the gap between the rigid insulation and the roof deck board, but you DON'T want to ventilate the space under the rigid insulation and what looks like a poor bit of glass wool insulation below. To make the best of a bad job you want to seal up underneath the rigid insulation so that the necessary air vents in the soffit board only ventilate the space above the rigid insulation. so the space between the rigid insulation and the wall plate needs to be completely sealed, and when the soffit board goes back it needs vents at the top to vent the space above the insulation.

^^ the above 2 posts give me no confidence you know what you are looking at or trying to achieve. Be VERY careful. Yes there can be a lot of wires the same colour in a light switch or a light fitting. It is important you identify them some way before removing a switch so they can go back as they were. I have lost count of how many times I have seen on a forum "I removed the old light fitting. I now have 4 red wires and 4 black wires, which one goes where please?" It sounds like you have neither loop at switch or loop at light but all cables connected from a BIG junction box, and at the rime that used to be common, it was common practice to just twist all the earth wires together outside the box, sometimes over the top to make it impossible to even get the lid off.

I would definitely use twin wall flue right from the stove, otherwise a single wall flue is likely to end up too close to the flamable walls so would require heat protection all the way up the walls. My finding with the cheap little stove in the caravan is the flue gets very much hotter than the quality stove we have in the house. Probably a measure at how poor the cheap stove is at putting the heat from combustion into the room and instead a lot more heat goes up the flue compared to the more efficient quality stove we have in the house.

Small air source heat pump driving wet under floor heating, will be about 1/3 the running cost compared to resistance heating. NO problem with wet UFH under engineered timber floor. It depends what you want, cheap install or cheap running cost. I would say the way energy prices are going cheap running cost is most important.

MVHR is the way to go. It is constant ventilation you want (with a boost speed when showering) Just get the smallest unit you can find, fresh air into living room and bedroom, exhaust air from bathrooms and kitchen.

My ASHP is an outdoor monoblock unit but I still have the noise described. It is the circulating pump and the water circulating in the pipework and the noise can be heard anywhere where there are pipes above or below the room. It is not very loud but I am very sensitive to noise especially at night in a bedroom. simple solution. set the timer so the heating is off at night. In a well insulated house you will not notice much temperature drop over night. And changing the circulating pump for a quieter one (Grundfoss or Wilo) will also help.

And just how do you propose to tape the membrane to the inside face of plasterboard? And if you manage that every switch and socket is a hole in your air tightness. The results will be poor. Do it properly, membrane the entire wall, battens to form a service void then plasterboard all nicely inside the air tight envelope. That keeps all your wiring sealed inside the air tight envelope.

Right at the front of the side wall would be my choice, i.e. facing about south west. I think sun does make a difference, certainly here, when we get a cold spell the north side of the house becomes a permafrost in winter but the south side is definitely very much warmer, so probably less defrosting issues. And although it may seem controversial to put it almost in the front garden (actually the side garden I am proposing) people tend not to spend time in their front gardens so it keeps any noise away from yours and your neighbours back gardens.

Who sized the GSHP at 12kW? If that is correct then an ASHP would also be 12kW. There are reported shortages of ASHP's as well so best of luck. some suggest the last gasp of the RHI is producing a demand peak to get systems in before that runs out.

The membrane is your air tight layer, why are you wanting to seal it to the inner face of the plasterboard? Normally the plasterboard is just something that happens to be inside the sealed envelope of the house.

200mm for me as that worked out nicely with 400mm joist centres. Works very well.

That link does not work for me. That might be because I am not (and don't want to be) a member of facebook.

Ovens don't actually use that much power, typically 2kW for a single oven. It is hobs that draw much more power. If you feel more comfortable and future proof use 4mm or 6mm for an oven feed, nothing wrong with being too big.