ProDave

Outside edge, compriband expanding foam. Inside edge, tape to your building frame with air tightness tape. If you are going for full air tightness you will be doing this anyway.

Are the collar ties being left exposed then? I would have thought you would just plasterboard that as a normal ceiling and then I don't see an issue with surface or recessed lighting.

Why is such a short span flexing? Why did you need to recess for the former? We used an Impey former (and tanking system) and the former fits within the 22mm of a normal floor board so same joists everywhere, and the Impey tanking membrane acts as a decoupler so okay to lay that on chipboard then tile.

Current version of the Titan https://www.screwfix.com/p/titan-ttb653sds-5-9kg-electric-sds-plus-drill-230-240v/6846h#product_additional_details_container It even comes with a spare set of brushes. Mine is 18 years old and an older design, now on it's third set of brushes and working just fine.

A very quick search finds this https://www.amazon.co.uk/Natures-Head-Contained-Composting-Quarters/dp/B009Z7EKIC So thick end of £2000 for two composting toilets (no doubt cheaper ones are available) That is roughly the cost of your treatment plant.

I know of one person that fitted a composting toilet and just ran sink and shower waste straight to a soakaway, and building control accepted that. But if your ground is no good for a soakaway I can't see how that would help. You could pump the sink waste up to an above ground filter mound system perhaps but I would hugely favour the treatment plant rather than that. Unless you are building a bungalow, building control will insist on a toilet on each floor so that is likely 2 composting toilets needed. What is your motve? something that is cheap and simple to install and proven to be reliable? Or something that is "greener" than a treatment plant?

I am sure we discussed this before? It's a no brainer. Air blower type treatment plant and discharge to your stream. It really is a simple and easy system with very little to go wrong and very little maintenance.

Soft start would remove the big inrush at start up that dims your lights and the DNO's hate, but would not allow the unit to modulate down to a lower power level. It would be wise to clarify if possible which it has. Most manufacturers are quick to highlight variable speed inverter drive.

Remember most heat pumps don't heat DHW and space heating at the same time, so no need to over size it to allow for both. That does mean of course it can't do space heating continuously 24/7 so if it needs a constant 3kW of space heating that might be more like 4kW if it is running less than 24/7 My worst case heat demand at +20 inside and -10 outside is about 2.2kW Mine copes nicely with the heating on for no more than 16 hours per day.

Re ceiling heights. We have gone the other way. All downstairs rooms are a pretty standard 2440mm (just slightly over 2.4M so no need to trim any sheets of plasterboard) but upstairs, the two main bedrooms both have higher ceilings, the largest going right to the apex of the vaulted ceiling, with a mezanine platform over the small bedroom adjacent.

Running the pipe across YOUR fields is just the cost of dig a trench and bury a pipe. you would want something quite large over that distance. I doubt Scottish Water would want to do that bit. If the field ditch is yours I would cross that yourself as well rather than paying to cross a road. do you have a JCB or digger on the farm, or even a back hoe for a tractor?

No I just have the one tank, heated by the ASHP to 48 degrees. For much of the summer, surplus solar PV lifts the temperature a lot higher than that.

My LG heat pump had an "optional kit" for a "sanitary water tank" (not my description) It was included FOC with my heat pump. It consisted of the temperature probe on a long (but not long enough) length of flex, and a box containing a contactor and a MCB. That box is wired to control the immersion heater in the tank, so if you want to, you can program the ASHP to do a legionairs cycle toheat the tank water to 65 degrees once a week. I have that disabled. So I could have installed the tank with just the temperature probe, which is a plain old thermistor.

Yes via a Telford 300L Heat Pump cylinder. Two bathrooms, kitchen and utility room. 3 people in the house. We have run out of hot water on a couple of occasions. Because the water is only heated to 48 degrees by the ASHP it will use more "hot" water than it would if it were hotter to run a shower. and given our showers are capable of something silly like more than 15L per minute, you can empty the tank in half an hour. And when the ladies get washing and conditioning their hair, two such showers can use up that half an hour. to guard agains that I have a Steibel Eltron instand water heater in line with the HW tank output https://forum.buildhub.org.uk/topic/8020-stiebel-eltron-dhc-e-810-instant-water-heater/?tab=comments#comment-136666

A quick scan through the SAP (section 8 ) tells you your worst case heat loss is just a shade over 2kW, about the same as my house. And mine is running fine from a 5kW ASHP running under floor heating downstairs and only in the bathrooms upstairs.

Certainly one to keep an eye on. but loads of nice fluffy words and absolutely no detail.

My guess (and it is a guess) would be the council. They may grant you a licence to drive over it or may sell it to you. Has anyone else nearby created a driveway over similar land?

He is making his life hard. Leaving the cut tiles until later which makes them harder to fit and they won't be nailed or clipped. So he's taking off natural slate and fitting interlocking concrete tiles instead. Does that need planning permission? Is the property listed?

The Anti legionela thing was discussed before. The conclusion was if you have treated mains water and a UVC it was not an issue. It might be a different matter with a private water supply.

I found the cheapest place to get one from was Travis Perkins. I think what swayed it was they could use their own transport to deliver it which they did FOC which made it cheaper than anywhere else.

If you have the option of discharge to a stream, definitely do that with a treatment plant. Way better and easier than any drainage field especially if it won't drain anyway. If you are worried about material, our Conder treatment plant is made out of hdpe, not fibreglass.

If you want to answer the RHI question, separate the quotes to general plumbing, and heating system (with or without RHI) on separate quoted. My gut feeling is there is too much to give a fixed quote. I know most people don't like it, but I feel certain you would end up with a better finished price on a day rate. I always maintain a fixed quote has to allow for the worst case of everything which may not happen.

Yes I had an Electrician from the Central belt try and tell me on another forum that I had to be registered with a competent persons scheme. I have never done work down that way so never put it to the test. A while back I worked as a subbie for a small builder and we did a few houses in Moray. I was fed the same BS about Moray council so the builder struck a deal with some other local electricians that they would test the installs and certify them. Until one day they "had some issues" and were not able to do that so I issued the EIC and Moray council just accepted it. It's all a load on nonsense to me, and I won't be sorry to be retiring from it all in a few more years.

Ah yes, make sure you are comparing apples with apples.

Mt findings is each Council must keep a list of electricians they have check. I never get asked now for any proof, but the first time I issued one in InvernessShire They phoned me to quiz me. So if you are new to them you might get asked.