Iceverge

Definitely this option. Out of principle if nothing else.

You can but there's a charge for it. A tariff if you will.

Depending on how much work you want you could always just dump say half the water every day and refill with hot cylinder water to hear it up again. Simple enough calculation to be done depending on how much you are paying for water Vs how much you are paying for electricity. Perhaps not the best use of water but that's your call to make.

Can you temporarily tee off a loop from the central heating and run a coil through the pool water? If you have solar PV you could chuck a cheap resistance water heater into it and just use it instead of exporting. Cost of running will be impossible to calculate without knowing your exact setup and pool. If it's an inflatable pool then you will have a pretty low heat loss so long as you insulated the floor and get a good lid. If you can get your hands on some bubble wrap it would possibly be a practical way to wrap a non insulated pool and you could cut a floating lid from the same.

Not necessarily, high temperatures are fine for Immersions. It's heat pumps that suffer. The catch with immersion heating is it's often best done in a small time window for the best tariff so you need lots of capacity. If you have lots of space or a fossil fuel boiler and/or a solid fuel boiler I think they are a good solution. With heat on demand like with an oil or gas boiler they act almost like a capacitor in a circuit to smooth the cycling of the boiler. Storing much energy is not feasible when you look at the physics if it. A 300l thermal store at 70deg will give you about 7kWh of usable DHW, or it might run UFH for under an hour in a well insulated modern 200m2 house. For the situation in my parents house they can still have pressurised DHW in the event of a power cut as the solid fuel Rayburn feeds the store on a gravity circuit and a small Genny does the water pump. As alluded to above a TS will have far more copper pipes hanging off it Vs an UVC, especially a direct UVC and these loose a significant amount of the energy, even when lagged when compared to the tank itself. Not an issue in a old farmhouse but may ( and has ) led to overheating of smaller or well insulated houses. TLDR, TS good for old houses on solid fuel or Gas/Oil with space for a large tank. TS bad for small/well insulated houses on an immersion or HP. G3 is simple to DIY, don't let it affect your decision.

Difference application but I bought some covered GRP grating for the thresholds of our house from eBay. Simply bridged the wide cavity block wall with it and sat the doors on top. The EPS blown beads filled the holes from underneath and thermally it was quite satisfactory. In computational reasoning at least. Stuff like this.

Cut out some of the XPS to allow the door frame to be partially supported by the concrete

I've done both. UVC and TS. From trial and error real life living the UVC will deliver useable 40deg water until the average temperature of the tank is about 30 deg. The TS is all out of ideas once the average tank temp is 50deg. Assuming you can store water at 70deg on an immersion then an UVC will give you double the hot water of a TS. If you have a heat pump you will have to run it very hot for a TS which will destroy your COP unless you have a really giant tank. That said I really like the TS. It does a nice job of combining heating, oil boiler and solid fuel cooker and pressurised DHW. It could take an immersion and solar too if needed. Both are pointless for space heating though unless you can hold 2-3m³ of hot water. For your situation a direct UVC on a TOU tariff would be the cheapest long term. Have you thought about A2A HP for space heating. Ours is proving economical. I do my own servicing, (no G3 in Ireland). Takes 15 mins a year. Check the safety valves, clean the filter and top up the accumulator. It is dummy level if you have any mechanical competence at all.

For plaster boarding I used to scribble the dimensions of the offcut in big numbers on it and stand it against the wall beside the pallet of fresh boards. Same with timbers. It was remarkable how often an offcut was almost perfect for an infill.

Nope, different beasts. A membrane is normally 1.5m wide, just a sheet of fancy reinforced plastic. A tape is only 50-200mm depending on application and has adhesive included. Along with your understated humility and bashfulness it's your best hidden quality.

Just reason back on Nicks suggestion. It's a good one. I just used a dilute solution of the airtight paint (soudal) as a primer. Going in with a neat first coat resulted in it not sticking very well unless everything was clean room decontaminationed.

Don't get too hung up on certified. Long term flexibility and dimensional stability is what you're after. Look for a product that doesn't shrink or harden over time.

That wide fit masonry tape is bungabunga party expensive. Cut a strip of normal airtight membrane, apply a bead of airtight sealant onto the ply floor and staple the membrane down over the top making sure the bead is continuous. Apply a thick bead to the wall then and press the membrane in place. A sausage tube will go a long way for £9.

Attic hatches should be limited in size to prevent anyone less agile and slim than a circus trapeze artist from entering. Amazingly Christmas decorations survive pretty well in a cupboard. Who would have thought it. If a single box kept out of the loft tips your house over the edge from austere bliss to hoarders bordello then you really have been living in the absolute limit. I would put the UVC into the utility room. Thermally vastly superior and central to all your taps. The only one that really matters by the way is the kitchen tap. Consider 10mm Hep to this if you can live with about 6l/min of hot water. You'll be rewarded by super speedy water delivery. Displacing something else out to the garage would be preferable in my view. Is there somehow preventing you having your ASHP right outside the utility? Absolutely minimising runs of piping outside the unheated envelope. Alternatively if there space you could put your UVC under the stairs.

At a guess I think this if for an external precast threshold. I'll keep an eye when I'm passing. It's a shame the boards are used. It's a generally well done site otherwise.

I had a look at a new site recently. Good job was done on the blockwork I thought. The PIR Was installed in the usual fashion, far far from the worst I've seen mind you. Gaps between boards, wall ties not fitting correctly, mortar droppings on the boards etc. I maintain it cannot be accomplished to a satisfactory standard in real life and shouldn't be attempted. Bonded EPS beads or mineral wool batts are far superior.

Premixed concrete I assume is much the same as a 3:2:1 general mix which I make up for £85/m3 or 2400kg. Bagged premix concrete is about £6/40kg at best or over 4 times dearer. I bought my ballast in a truckload though so that may not be convenient for everyone.

I mix a fair chunk of concrete here in a 300l tractor mixer. The mixing and filing time are the main limitations on output. It was less than half the price of that and I can do about 1m³ per HR if I'm mixing only. The this is a nice machine if you can use it as demonstrated and continually feed and pour directly into your forms. However if you want a particularly lean or strong mix I think you're stuck with what comes out of the bags. Once you need to stick a wheel barrow under the spout I think all the advantages disappear.

Or build it on a floating circular raft in a circular pond. You could motor it to face the sun like a flower. PHPP would love that.

No reason why it wouldn't work. Does it limit you to pre bagged concrete though?

Unusual spec this. I'd prefer Type 1 Insulation DPM Insulation Pipes staples to insulation 100mm concrete powerfloated.