JohnMo

A gas combi boiler uses a pressurised heating loop, as described. The alternative is your existing header tank.

We have UFH in bedrooms, wouldn't do it again, slow to heat up, slow to cool down, never the right temperature really. Towel rads either electric only or dual fuel (electric/water). Just do something like this for bedrooms, for heat and cooling. https://coolenergyshop.com/collections/radiators-fan-coils

Issues 1. With a combi tank the thermal store header/expansion would be below the level of the upstairs rads meaning they'd need to be decommissioned. Could you run from coil in cylinder, then no issue supplying upstairs rads, just run a pressurised heating system?

Wow £3k, mine about £150, including the tube heater and half sheet of 25mm PIR on the door and hinges and bolt.

Pallets, insulation, VCL, cladding boards, sarking boards, breather paper, all left overs from build. Only added roof sheeting. Needed a shed to hold water borehole filters and pump control. And log store X2. So build this.

I have a wooden garage with steel roof. Mine is surprisingly cool inside, full sun most of the day. So metal roof, breather fabric, sarking board on roof rafter, 100mm accoustic mineral wool between ceiling joists, 25mm PIR below, fully taped. Walls similar, but without the 25mm PIR, just used silver bubble wrap.

But you need at least 6 of the solar collectors linked to give 70% saving in DHW in July. So realistically you could have 9 or 10, so are over £1k just for panels, which is in the 30 evacuated tube price range.

If your leakage rate is greater than 3m3/m2 @50Pa, keep your money in your pocket. As cost to run v savings made will not be a benefit to you. I would instead (irrespective of your leakage rate), look at a demand based MEV or dMEV, more cost effective to purchase, simpler to install, run and maintain and only ventilates at the rate required.

All my 50mm battens are fixed with 90mm nails, unless they are screwed to woodcrete. I have all the ceiling battens and the second layer of external battens (for vertical cladding) all nailed with 90mm

I looked at those and for a house need quite a few, which ended up being quite expensive.

This how I did mine. Nail into the side of the rafter, so the nails have to shear, rather than just fall out. The center section were skewed nails.

Your boiler has weather comp built-in. Go on to heat geek website and have a read up on weather comp.

Confused, what's not condensing? Condensing with natural gas starts with a return temp of 54 degC and lower. The lower the return temp the more condensing that occurs. The more efficient the boiler becomes. With UFH there is no point heating water up, to then mix it down to a cooler temp.

Ours was £4k with slate hearth, the flue, air supply pipe, full labour and Heta Scanline 8 full soapstone. Costs don't stop at just the fire.

If it's UFH, why are your flow rates to high? Seem high temps.

Don't buy a big sand hill. Views great, but landscaping costs are huge. Less glass, or Aircon from day one. More solar. More insulation. No more than one thermostat in the whole house. I had loads caused loads of issues with the heating and short cycling of the boiler.

12 degrees makes it a normal roof, less than that it's a flat roof. But the third person today that wants to miss a designing it correctly stage and make up as they go along.

Insulate

Why are you doing building work without proper structural engineering input. Flat bar will do nothing for you structurally. Primer does not provide rust resistance, it is porous to provide a key to finishing coats. It will rust in no time at all.

We have almost stopped using the recirc extract, just put the MVHR on boost job done. Only really use for smelly cooking.

Can't understand why you would build and not have a structural engineered design and then follow it. I like the Scottish rules, no structural design certificate, no warrant, no build. Keeps everybody right.

With all boiler types you get a big drop in efficiency, every time you go through a start cycle as all the metal parts soak away the heat during the heat stabilisation phase. Reduce zones as much as possible, no small zones, try to reduce central heating flow temperature so boiler has to run for longer. Low and slow, is the way to go.

I used Passive house systems Hi-Thermia Reflective Membrane. Has a mesh woven in doesn't tear, easy to work with

There was another thread a few weeks ago on the same subject, they concluded it was possible. Have a search.

We have a 3.1kW if panels installed and saw 3.05kW being generated, so no issue with mounting direct to sarking boards. I did quite a bit of research before mounting direct to sarking boards. Everything I read led me to the conclusion that in Scotland, it's not an issue with overheating, and if there is an issue your performance drops while the panels are too hot. Southern England may have an overheating issue, but they get better PV production.