JohnMo

I just got my ground contractor to do it. Normal concrete lorry and in our case, but because of distance and access, we use a concrete pumping lorry also.

I wanted as the OP to do the screed before walls, so just used a normal concrete, it really doesn't care about the weather. For clarity we have zero screed, just concrete over the UFH pipes. My build-up is 200mm rebar concrete slab, then 200mm PIR, then as described further up thread.

Buffer and secondary pump and zone valve just delete them - are they needed? Most likely not.

No switching of switches required, it just does it automatically both ways. Generally no idea if there is a power cut anymore. You can see a change in trend data on the app if you look.

Depends on the inverter. I have an all in one AC battery setup, it keeps G98 approved PV inverter online with mains off. It also delivers a continuous 6kW plus PV output with mains off.

Yep No, like this, insulation (PIR) polythene barrier sheet, UFH pipes clipped to insulation through polythene, then 75mm of concrete. Power float smooth. Just like this

Just do concrete, not screed. No effect once cured with weather. Just do fibre reinforced if you need anything. We concrete with fibre 100mm thick.

Doing it again, I would most likely do a version of twin stud construction. And construction stick build on site. No big deposits to companies, builders merchants only delivery as required.

Pretty much.

Only once had an issue, but tried to light it in 60mph winds it wasn't happy. Now just use a fire lighter and it starts every time even with 60mph winds

You need to clean more often. Just get the window cleaner to do them, ours uses a demineralised water and a huge extension brush arrangement, so is done from the ground. Most window cleaners do it that way now. We clean our twice a year. You don't need any chemicals or other stuff.

Why not ICF, pretty easy DIY option. Our walls (200m² single storey upto 3.5m tall) took two of us 4 weeks start to finish.

We had our fire (stove on) when temperature dropped very low (about -6 and below). Although the room temperature was still about 20 to 21, it just felt cooler. Lit the stove and moved the house temperature up a little. Secret is don't overload with logs, heat output is proportional to how much fuel you add. Other factor is get soap stone covered stove, this slows down the output curve considerably. And use the air regulator. Decommissioning - empty ash bucket, done. 5 minutes later complete. Low energy how and stove works, just a matter of sizing correctly, specify correctly and use sensibly. Our first use of the fire caused overheating, but I fully loaded with logs, so no wonder really.

Another good reason for no internet connection to any household systems.

Sorry my view, they are taking the p!ss with mine and your tax money, they don't deserve the trade. And that's my highly editted version.of my real thoughts.

You do really - they are busy and just doing high paying work. Quote everyone high, the richer mugs will pay, so we will keep doing that work, until it dries up

People do over think stuff. With MVHR, just do a recirculation hood. The times you actually need to use them is few and far between. Cannot now remember the last time the hood got switched on. MVHR does most of what you need on its own Keep it simple

Just buy yourself a Panasonic to suit your heat needs about £3.5k, cylinder2go heat pump cylinder about £1200 from memory. Find a plumber to join it together with a 28mm 3 port diverter valve between cylinder UFH. If only UFH no need for mixer or pump. Expansion vessel and relieve valve after tee from cylinder return and a filling loop and a strainer. That's about all you need. So where these rip off merchants get the prices no idea. I just did myself, I paid £1300 (ASHP), £1000 for cylinder and another £600ish for stuff. Spent a few days installing. Got electrician to do wiring hook up. Zero faff, bought what I wanted, no justification about sizing etc.

Try 27, 28 with blinds closed, worst case is during shoulder seasons, when sun is low without cooling. Living room is 6m tall, but with fully glazed end. Although we have large roof overhang when the sun is starting to fall in the west we get the sun all gun blazing. Yes we close blinds. Cooling went on at begining April this year. Heating one day, cooling the next. done that it's still way to hot at bedtime. UFH in cooling mode temperature drops to normal levels before bedtime. We still open windows and doors about 4 to 5pm. With cooling house recovers quite quickly. 2 degs outside the last night, was still 19.5 in the house this morning. Staying in England tonight and had the heating on where we are staying. Quite bizarre we are near the top of Scotland have cooling on and currently 20.8 in the house in Scotland and the house in England with heating on is about 19.

Difference is pretty small, you are only exchanging the house air every 2 to 3 hrs. So don't expect much if any heat movement. Solar gain is way more powerful. I bought an ASHP for one reason - cooling. After living in house for one summer

You do not add target airtightness you add air changes per hour. Lack of airtightness add to the controlled ventilation by about 5%. So airtightness of about 2 m³/m² will add 0.1 to any controlled ventilation. So 0.5 becomes 0.6. (think those numbers are about correct. MVHR set recovery to about 85% anything else set to zero.

I would replace all trickle vents with humidity activated, then no one can sneak the vents closed, as normally happens. These stay a little bit open for background ventilation and as room humidity increases they open more. Make sure there are no trickle vents in wet rooms or kitchen, these will make the fans just draw from that rooms ventilation, not the whole house. Make sure all internal doors have at least 5 to 10mm clearance at the bottom. This allows building cross ventilation with doors closed. The fans in wet rooms should be almost silent, they should be set to building regs flow rates, and ideally automatically boost based on humidity, not via a switch. Next ensure building is signed off as complete before handing over any money - or YOU could end up having to install MVHR to satisfy building control.

Blinds or curtains closed first, UFH or fan coils connected to heat pump second. PV to power heat pump 3rd. It's sunny here and has been for a few weeks. Average temperature yesterday was 9.5 degrees and down to 2 degs overnight. However we have the cooling on and it's been on for the last month (except a few days). Well insulated, quite airtight and lots of glazing. Apart from a brief period 5pm to 7pm house stays pretty stable at 20 to 21 degs. PV pays for the heat pump to run. Generally running the house, ASHP etc paying about 80p a day for electric, don't get paid for export otherwise it would be free.

Just a big standard 100A single phase, job done. Shouldn't need any more than a 6kW heat pump, that will pull about 1400W max during start up so just a minute or so. Induction hob and charging is rarely done at the same time.

As @IanR says is pretty much what Scottish rules say also, for any Scottish viewers. Next steps are dMEV or MEV, 3m³/m² or worse continuous extract. Almost silent fans run at a low rate, with trickle vents. But you can add a condition based system. So trickle vents that modulate automatically in response to humidity levels. And fans that do the same. Then there is intermittent fan and trickle vents. Generally for 5m³/m² or worse from memory. Trickle vents can be through wall or window frame, can be fixed or automaticy. You also passive stack, and PIV.