JohnMo

If you have a cheap overnight tariff then heat at night, if you have solar heat when sun on the panels. Other than that when it's most likely to be warmest.

Why not keep the standing seam look and move from metal to a mechanical fix welded seam EPDM like Sarnafil? The seams are heat welded on profiles

I used 100mm PIR and there was 100mm concrete

City plumbing is also competitive with most pricing. Shop around for pricing.

I used left over PIR insulation, around areas like this, was easy to break out later, make big enough to give some wiggle room to move around later and make connection easy. Once you are ready back fill these areas with concrete if the need too, or leave as is. Our construction is slightly different from yours, 200mm reinforced concrete, 200mm insulation, 100mm concrete. First image is prior to first concrete. Second image just prior to second concrete, where you see the pipe stubs coming up, these were encased in PIR but only on the second pour.

Thinnest screed is no screed, just do a floating floor on pre grooved insulation panels. Not suggesting this company but the first one that came up on a search https://ambienteufh.co.uk/product-category/floating-floor/

Mostly sorted, the room with a bit of echo is the living room, but it's a 6m2 room with a a wall of glass and vaulted ceiling, so 6m tall also.

Buy a pair short ski's or snowboard. Small dry ski slope? We used 8" diameter posts to hold our bank back. Think they are 3M long, with a meter concreted into the ground. .

The noise changed in the house when we installed the plasterboard. The parge coated walls and stud walls filled with installation, was nice no echo and very silent. When plasterboard went on there was a lot of echo, this softened again as soft furnishings went in. But did prefer the noise or lack of, prior to plasterboard.

In Scotland the norm is to dry line, tapered edge plasterboard, taped and filled. Then painted or papered. Rarely do you see plastered walls.

Don't bother installing and get on with life, you will use for the first month and be really happy, then no one will ever use again.

Plasterboarded and taped, not plastered. Didn't insulate in the 50mm void, would if I did it again. All our ceilings are vaulted and insulated between and under rafters. Basically 350mm of spray foam. AVCL, batten service void and plasterboard.

Nothing wrong with A2A, can be very cheap to run. But has to installed by certified person for F gas. No grants, but should be vat free. Is it an Airbnb type of rental or long term? A cheaper more sensible option would be to spend a little to make your heating controls not playable with and more automated, with simple sensors that says window open heating off. Have time control wireless, away from end user in your hands.

Beam are based in Belfast, they sell Titon MVHR units rebadged, at less cost than direct from Titon, worth asking them.

Parge coat was a double cream consistency mix of cement, lime and soft building sand. Mix was applied with a soft broom, just enough to fill the gaps in the block surface. I used 50mm square battens, screwed through the parge coat into Durisol block. I used a CT1 sealant at the point where the screw broke through the batten to help seal. I used airtight paint at the floor wall junction. On the wall to roof junction I draped the avcl membrane down the wall 150mm and used airtight sealant to seal to wall. Some photos

No idea, worth a question - I just designed and installed myself. Pretty simple once you get your head around the requirements. I used 90mm semi flexible duct and a combination of normal terminals and Coanda effect supply terminals to keep duct length as short as possible.

Just thought you need complete sections of wall, so the concrete doesn't just come out of an open end.

Yes it funny to watch, grey slug goes in the top, clear water out the bottom. The structure of the blocks and the resulting concrete shape, is like a lattice structure, not a solid chuck of concrete like polystyrene ICF. Don't see any reason not too. We had had some very small sections of wall between doors and corners so these were filled by buckets, so as not to move anything with the pressure of a cement pump.

Not that was specified by Durisol or structural engineer. I was was pouring in December so plenty cold enough.

Assume you will have a separate heat source for all this hot water, as it will be busy most of the day, either reheating water or making up for the heat loss. Plus may be, if well insulated you may not need much other heat in the house, if you can distribute the heat coming off the cylinders and interconnected pipes. But plenty of cooling in the summer required. Quick calc makes about £10 per day on DHW alone, assuming CoP of about 2 to 2.5. £3.5k a year - you must have deeper pockets than most. Have you looked at something like this, which may offer more flexibility. https://originaltwist.com/2016/06/23/eco-heating-system-for-heat-pumps/

No plasticiser, less than 10mm (I think) aggregate, very high slump. The water basically drains away. We had 2 deliveries of concrete, plus a batch mixer for about 4 hours (for a part fill of Durisol by bucket and several other concreting jobs around site) and 2 hires of cement pump.

We used Durisol, would use again. 365mm will give you a wall with a U value of 0.14, but only if you include a service void, if the plaster direct the U valve falls slightly. Do not get a normal builder to build with Durisol there is a high probability he/she will balls it up, the corners especially. You can screw things directly to Durisol (with the right screws) such as service battens. A service void make plumbing and electrics easy, otherwise you have to recess them. Durisol is very abrasive, so will wear cutting tools quickly. You have to read and follow the build manual, once you start pouring the concrete there is no second chances. Concrete used as like water when it goes in, you cannot use vibrating tools to help compact, hence the water like consistency, the water open nature of the Durisol structure allows the concrete to naturally dewater. You will need to factor in several concrete pours and possibly cement pump hires as you fill with concrete every 6 layers (1.5m or so). Have the architect design the flow of the building around the size of the blocks (corner to corner length, corner to window opening etc) and don't have too many corners (unlike our house). Airtightness - Durisol is not airtight or water tight - advantage and disadvantage. You have to know where your airtightness layer will be and it has to be continuous, so something to think about. Mine was inside so a could make the roof structure airtight inside also. So I parge coated the inside, but you also need to seal the floor the wall junction and roof to wall junction and around window/door returns. My parge coat was a concrete/lime mix and wall remains breathable. Some food for thought

CoP or coefficient of performance. Is basically how many units of heat you get, for how many units of electricity you supply. So a CoP of 3 is one unit of electricity and 3 units of heat. The lower the difference between outside air temp and the water heating temp the better the CoP. So heating water to to 25 degs yields a better CoP than heating to 50 degs.

Isn't this a cut and paste of another topic you recently started? So back to your original question. MVHR and HRV are basically the same thing, they take air from the house and at an efficiency of 70-90% heat the incoming air. The other spin on this is MVHR with built in heat pump. The later is good for heat a DHW cylinder but not convinced it will also heat the house. The next option is some form of post heat on the supply to the house after leaving the MVHR unit. As mentioned above is constrained by flow rates of the ventilation system. As a side note not cheap and generally needs high flow temps so not best partner for an ASHP. As I like saying keep things simple, ventilation let it be ventilation and get on with ventilation. Heating and DHW can be done with a single heat source of your choosing. UFH in a well insulated house has low flow temps, so an ASHP ends being the cheapest to run, and you can cool the floor in summer for free if you have solar.

Can't you just switch to economy 7, electrician to make a few changes to consumer unit - job done. British Gas offered me economy 7 the other week, so it's an available option. Your other options are ASHP, with big radiators run on weather compensation. Multi room a2a heat pump. Both multiple thousand pound options 'v' a couple of hundred for E7.