ProDave

Not familliar with that calculation package you are using? What units are the 2 rows of numbers, what are they telling me?

So split the tails between the isolator switch and the CU's. Why 2 CU's in the garage? that's a lot? Is the house joined to the garage?

Then 16mm should be fine. I run our whole house on 16mm over a 22 metre run. It will need to be fed in the garage from a switch fuse with an 80A fuse. Tails split with henley blocks if not already there (picture of what's in the garage please?) You really really really want to avoid having to have an RCD for this in the garage. So this will mean either SWA cable, or if you can route the cable on the surface or in trunking you could use twin and earth.

That will be too little insulation, and insulation of a type (probably PIR) that has a very short decrement delay so by the afternoon the heat will be streaming through the coombed ceilings. Our new build with plenty of insulation and a type (wood fibre and earthwool) that have a longer decrement delay has none of these issues.

Thought it worth adding my electricity use findings: Absolute base load, while away on holiday. Just Mvhr, Treatment plant and one sky HD box left on to record some stuff = 4.4kWh / day A similar test to above, away for a week, but this time also a second Freezer left on, and a few tv's on stnadby 6.5kWh / day. So second freezer and standby tv's using 2.1kWh / day. Normal usage with us in the house = 10.4kWh per day. So everything we "use" (over and above the background load above) is using 3.9kWh /day I regard this usage as "high" probably because the electricity used to power "stuff exceeds the electricity used to heat the house and hot water. Worth noting that these holiday background tests were in the summer, so the real background usage will be more but most of the daytime background use will have come from the solar PV, this is just a measure of what was imported, which would have been mostly at night.

Distance between them and loading? If I came down to Aberdeen I would have to quarantine at the moment?

Hi and welcome. I do believe you are the first from the IOM.

I would just rebuild on the same footings then.

Having seen the site layout, I would go completely back to the drawing board with a new design and resubmit to planning. The bit of garden to the left of the house as shown on the layout plan, will get most of the sun. I would want that to be my main bit of garden. I would want to move the house a bit to the right to make that bigger. The bit of ground above the house (straight on from the drive) is where I would put your car parking and the entrance door on that side of the house. I see no reason for it's odd shape that makes construction more expensive and makes internal layout more awkward, I would go to a simple rectangle.

Is the soil level in the garden higher than the pavement? Is that's what's pushing it over? If you you will need to widen the footing inside the garden to build it as a proper retaining wall, wider at the base (underground) on the garden side.

Nothing about this design flows. Lots of disjointed odd shaped rooms. I don't even like the position of the stairs. Stairs rising from the living room should be for small houses where you have no space for a hallway. And why does the upstairs shape differ to downstairs? Overall dimensions and a site layout might make more sense of it and enable suggestions how to improve it?

Don't like their "flush mounting box" it makes them so bulky and ugly. So it's either that, or a big hole and poke a junction box up. Or just buy aico.

Ah so that sloping ceiling with the window panels in it is a completely false structure and not part of a roof profile?

Ours came from Stone Source in Inverness. they have a yard full of huge slabs of stone of all types to browse and choose from. And their service and fitting was excellent.

Do you have a stone supplier near you? if so go and have a look. Quite a lot of Granites are light colour and may suit your preferences. Ours is definitely impervious to just about anything including red wine.

I have mounted Aico alarms on a wall in a similar situation with approval from Aico and accepted by BC. You must have picked the tea boy to answer your questions. I forget exactly but I think it had to be >300mm from a corner.

Aren't the Kidde ones the sort with flying leads, so you have to cut a bigger hole in the ceiling and come prepared with a load of small junction boxes to poke up the hole? That's why I like aico, just about the only ones that provide a proper terminal box.

A full plan would help, do you have the joist plan for that floor?

I uses the spread sheet above. What really annoyed me is I could not get a definitive answer to the actual extraction rates required by Scottish building regs. Even a call to the duty building control officer did not help, so I have done mine to the English regs. I will find out in due course if it is accepted, but if not I will say well bloody well give me the rates that the Scottish regs require then.

Must be a more easy going sparky than me. Some makes of alarm are not exactly easy to connect.

What do you perceive as a problem with a longer decrement delay?

Aico all the time for me. you won't find another that's better for wiring and neatness. I usually buy them from random ebay sellers for a much better price, but check the "replace by" dates as some are selling old stock near the end of life. I particularly like the fact Aico do a combined heat and CO alarm in one package, perfect for a kitchen with a stove or boiler in it. I just wish they would make a combined CO and smoke alarm as well. What questions do you have that they could not answer?

Middle of the day for us (it will be going on shortly) so it can run from the solar PV power.

In a new build you would hope that the level of insulation included means warm up times will not be an issue. In our previous house, built in 2004 that had UFH upstairs and downstairs. It was noticable that upstairs took longer to warm up mainly due to carpets slowing down the rate of heat transfer (solid floors downstairs) In our present house, it is so well insulated we do not have any heating upstairs. If you choose radiators, they will need to be over size / low temperature, to work with an ASHP.

Winter ASHP usage for water heating is typically 25kWh per week. In the summer that can drop to less than 10kWh as a lot of the hot water comes from the solar PV. It's actually better than that, as my meter still measures how much the ASHP consumes but in many cases most of what the ASHP is using in the daytime is coming from the solar PV. That is for 3 people.