JohnMo

T This sounds like the conversation I had about cellulose, they wouldn't even quote until I had all the drawings changed to suit what they expected. So zero idea of costs without going back to architect to amend drawings - so moved on.

But to do this you first need to understand what the boiler does and doesn't do. You can make massive reductions to gas consumption just by running the boiler differently. I more than halved ours with no other changes. Combi they tend to be big (generally massive, compared to heating duty) and sized purely on the basis of hot water. To get them to run well, you need a boiler with good modulation - most are rubbish. The higher the minimum output (at 35 degs) the bigger the water volume you need, so big radiators are good, zones are bad. A simple design is best, but designed well. Your bog standard install will be high flow temperature, small radiators, lots of thermostats. Most boilers short cycle a lot, but knows or cares, they just lay the bills, because gas is pretty cheap.

Something isn't correct, I would start with a decent heat loss calculation and go from there. Big rambling pile with a wall missing maybe 50+kW, but would more likely suspect way smaller.

From original post Heating and hot water are different heat pump - or at least that's what I read?

With a boiler If you are set on a combi, a storage combi would give better hot water performance. Then oversized the radiators so you run a max temperature of 45 or lower. Run either weather compensation or load compensation on a single zone, with simple TRVs on bedroom rads to limit room temp. Ideally complete a room by room heat loss calculation to size radiators, not a plumbers thumb in the air guess.

Are you sure you have a 56kW heat pump? If so you must be heating a castle. 2000L will contain 46kWh with a start temp of 55 and dropping to 35 degs. So not much, plus you take a huge CoP hit heating to that temperature, so why bother. Think you need to think simple. I would say dump the buffer altogether, if you need more water volume (approx 20L per min kW output of heat pump), use existing buffer as a volumiser for heating system. So connect in supply or return line not both. You can delete the secondary pump. You need to look at zoning also, i.e. remove as much zones as possible and the ones that exist make as big as possible. You want heat pump running low and slow all the time generally - not the red days obviously.

Crates are really an alternative to what we did. That design just follows the recommended design by SEPA. If you have space its easy and almost no material costs.

https://www.cotterillcivils.co.uk/blogs/guides-to-flood-management/how-to-install-soakaway-crates?srsltid=AfmBOoohgOP6ReHBhn3MNaLCNlKWv0QntWy-0RO-CJBHyVViWn_e6_77 We didn't use crates at all, just slotted 110mm pipe in crushed gravel, geotextile below and above. The pipes were covered with more gravel then geotextile.

Come on now, you can't simply tick a box that says "eco" if you need to do some justification. That just isn't a easy to do.

You may well have included all this, but just in case Have included the grout spacing in your calculations be a shame if it doesn't match perfectly. Will you be skimming the ceiling or dry lining have you included this in the calculation? Also, if a shower tray will this be bedded down on anything that may elevate it?

If using crates follow manufacturer instructions?

Back to the good old days of oil lamps then

Put a doubler on to strengthen. To do this correctly you would drill and bolt both the doubler and the original joist. So you are making more holes, is this fixing the issue? What issue so No. Will filling make it look pretty possibly, will it add and structural integrity - No Move on with more important stuff, like putting the floor boards down so no one breaks their neck.

In our last house we had GU10 led things (if not bulb, what do you call them?). They had a poor installed life, tried a few differences they were all rubbish. Think the main issue, the GU10 holder isn't optimised for the cooling LEDs need, so they overheat and fail quickly, dimmers and 7W don't help either.

I doubt you would add any structural integrity by filling holes. Wouldn't overthink it. If you are finding loose boards, sounds like like an older not new house, so holes have been there for years, why fix it if it isn't broken

I did ours at 600mm and had to alter to 400mm

Electric UFH, you will be paying a second mortgage, about 4 to 5 times the cost of gas. UFH isn't a small job, are you ok rising the floor. Any possibly getting the floor screed?

I would get some 25mm PIR insulation. One sheet should be enough. Also get some aluminium tape and mineral wool or B&Q do some white plastic wool insulation. So make a box out of PIR to insulate the manifold and pipes below, cut to shape and tape together. Fill with wool insulation, make a spacer to wedge the whole thing against the wall from the MVHR unit. The metal pipes also need insulation, you do similar to above.

We have had good weather, but maybe not as good as yours. Won't hurt to give it all a clean and make sure I have no issues.

Clean and check over tomorrow, I think for mine.

Watching with interest

Superfoil in that situation will add almost no insulation value. Don't you have acoustic insulation between your joists? That will provide insulation. You could could just do egg crate panels screwed down and the screed over

Here are two weeks a year apart. Above 2024 Above last week I thought this year was better, but seems last year wins.

We also have 20mm (oak) flooring, but pipes at 300mm centres. There is zero issues I generally flow at 35 degs, floor temp has never been above about 24. The temperature through the pipes is dispersed via distance, as heat radiated outwards. Floor temp and flow temp are different things

Use what is linked in the video. 20mm insulation is a waste of time in the grand scheme of things. Adding the insulation in this case just decouples the existing slab from the UFH. You are better having it coupled, then run low and slow per video. You will suffer downwards heat loss, but that is true with any of these systems. Not sure I would trust a super thin layer of screed on top of the 20mm insulation. Cracks etc.