JohnMo

I found the network provider, installed the line to the meter box. I had to then get the gas provider to install the meter. Only when the meter is installed do you pay line rental.

G98 form?

Remember the insulation value they are quoting is R value, not U value. 1/R = U. So in simple terms. 1/0.447= 2.24 U value; which is pants.

The 20mm system will be loosing 2.2 W per degree per meter, you'll be loosing about 0.1 W. So it's not that good.

And now doesn't, £14.2k install, to get £10.7k back. So based on your own basis for having it installed it doesn't stack up.

Never even thought about getting a warranty, would strongly suspect they aren't worth the paper they are written on.

If you are not retaining anything, (IE just a wall) not sure you would need any rebar. But it depends on how high wide you make it. Download the Durisol manual and/or speak to them.

Not sure where you live. But in Scotland, you have to have a heat alarm in a kitchen area, you cannot install a smoke alarm. Every home must have: one smoke alarm in the living room or the room you use most one smoke alarm in every hallway and landing one heat alarm in the kitchen All smoke and heat alarms should be mounted on the ceiling and be interlinked. If you have a carbon-fuelled appliance – like a boiler, fire, heater or flue – in any room, you must also have a carbon monoxide detector in that room, but this does not need to be linked to the fire alarms. If an area is open plan, one alarm can cover the whole room provided it can be located where it is no more than 7.5 metres from any point in the room. If your space includes a kitchen area it should be a heat alarm rather than a smoke alarm

Trouble is how are you going to provide ventilation to living and bedroom spaces? Not the prettiest, in my opinion. To comply with building regs you will need them in every room. They only have two speeds and boost. Have a look at Prana https://ecostream.org.uk/d-mvhr/ They have better features and more adjustable.

PIR has little or no sound insulation value.

We used 100mm concrete, slow response, which suits us as we like a steady temperature, one heating cycling per day. We have 200mm PIR below the the UFH pipes.

Wouldn't want one on my doorstep. Polluting the sea is one thing, polluting many thousands of homes not that good.

You can generate electricity from gas at around 60% efficiency, using a combined cycle system. Where the gas turbine drives a generator, the exhaust gas is used to generate steam and drive a steam turbine; which also drives the generator. But once generated, you get system losses to get to the end user. Which brings down efficiency. The beauty of a gas boiler is it converts to heat in the high 90% efficiency, if set up correctly and no distribution losses at the point of generation. Yes other countries, use the heat distributed to heat homes, water etc. Our power stations are well away from residential areas, so does not work.

Possibly the worst of all things as far a cost to run and performance. 3 to 4 times the cost to run compared to a heat pump or gas. Low flow compared to gas combi. Would it be better to use E7 to heat a unvented cylinder for DHW, or a combined cylinder heat pump, basically the same price as gas or a third the cost if run on E7. Space heating with an all in one aircon/heat pump (no outside unit, just inlet outlet through wall), if you have UFH Willis heater's run on E7. Summer heating of DHW with solar either PV or/and thermal solar. That's my thoughts. If knew how our house performance a year before moving into it and wanted all electric. UFH with Willis heated on E7, combined cylinder (stainless or duplex) and heat pump, immersion diverter and solar thermal for shoulder months when PV performance is low for DHW.

Would have thought if it's structural, it would be graded C16 or C24, not bog standard CLS

We have UFH in bedrooms, (single storey building) the issue I have with it, is once it's on, it's on, no turning it off when you want to go to bed, so pretty much a waste of time. If we need the room warm we open the doors and within an hour it's the same temp as the rest of the house.

thermal lightweight aggregate, screed with EPS beads mixed into it.

Are you building a nuclear proof bunker? That's one thick floor. What are the rooms on the first floor? How well insulated is the house? What is on the ground floor for heating and insulation?

We didn't install in these places. Under beds. Under fitted bedroom furniture Under kitchen units. Store room. Under bathroom furniture. In hall or utility, as all other room piping passes through hall and utility.

Not sure why people take years to build a house, a weekend should do it. Few hundred pounds with kitchen and fire and woodcrete insulation.

13/14 for me glued to concrete. No issues so far. Just follow the recommendation of the manufacturer. UFH performs well. You are unlikely to sand, our last house looked great after 10 years.

Heat during the night on cheap rate, as well Insulation etc. Or ditch the UFH and install radiators

Joy of England, we can't get the warrant until structural engineering is completed.

Isn't it defined in your structural calculations what you should be doing?

We are not in the Highlands, but have an IV postcode, and still supplier want to rip us off. eBay is as bad. But if they don't give me a good deal on delivery, I just look elsewhere.