Andeh

I wonder if you could do it in a series of steps to encourage the water down the right direction? Not sure how you would create a reliable fall in one direction?

Very interesting!! Thanks for sharing, I am surprised. When I tried to contact Samsung about this, they refused to engage with me because I wasn't an installer!! Could have pretended to be one I guess, but then my questions would show that I am indeed...not an installer!

I'm not hearing any alarm bells ring from a quick read. We're at about 240sqm non passive/2.5 air tight, but still well Insulated... Yet inefficient home (bungalow, high ceilings, lots of glass etc) with a 12 kw ASHP. We run dish washer and washing machine daily and average about 35kwh during mild winter up to 50kwh during very cold spells. System will run luke warm all day during these periods. That's normal. DHW priority over heating is normal, 300L is your hot water not UFH, second tank would be UFH buffer which is optional but for big homes not required. We don't have one. Your 40kwh seems reasonable enough to me. Wouldn't worry about it.

Self leveller compound?

Still sat here waiting. I'm sure we'll get an answer.... Any..... Minute..... NOW! 😆

Dead easy, just stick a lot of PV on the roof. We snuck in with our new build, above average insulation, 4kw solar array. Not sure we deserve it with windows and very in efficient floor plan (big sprawling bungalow with high ceilings) but I wasn't going to argue!

Following with interest as I need to do the same at some point!!

I'd just use a regular polyfill for that sort of hole, and a painters knife! Let it dry, sand it, do it again, sand it... Until it looks good under a torch (if in visible place) then paint with roller or whatever the original paint was applied with in that area.

They say the third one you get right... 😆

OP, i don't think your ASHP is the problem here!! You yourself have said 6000kwh in 10 months... That's pretty normal, and isn't massively far off what we're prob using with our ASHP....albeit we are a large/sprawling bungalow. The ASHP doing the hot water and UFH is costing you maybe £170 a month. Yes increase the DHW to 50 degrees is a good starter if it's causing you problems. Make sure weather compensation is turned on, YouTube, asking on here or getting the installer it another installer to come out and check is worth doing. The issue you have is a farm and further units costing another £5k a year in power....you need to be getting seperate meters installed so you can actually properly assess where that power is going!

And as said.... Something isn't adding up, 6000kwh used for ASHP, assume 7500kwh for total annual usage, at 26p/kwh is only £160 odd a month. Probably a bit less with solar panel..... All seems remarkably normal?? Your problems are elsewhere, your ASHP is working perfectly fine! It's running for long times, at high efficiency, low temps, giving you a warm house for pretty reasonable heating costs. Edit... Also, we changed our hot water temp to 50 degrees for winter usage and the impact on things hasn't been much, certainly not enough for me to feel the need to change it back!! Yes 45 is more efficient, but probably only to the tune of a couple quid a week.

I spent most days obsessed with insulation and checking and monitoring.... But was away with work for the screed pour, and only this winter found we have a thermal bridge from big sliders against our screed floor. The first 6" of the screed is noticable colder... Like I said, you can't win everything! Reality is though... How often do you stand with your toes against the glass, room is still lovely and warm, and overall house is very reasonable ££ to heat...wife thought I was crazy when I be moaned it. No one else will ever notice or care, but it's still taken me months to get over!!

I don't think 6000 for nearly a years usage is THAT bad? For an average newish home. Especially if you are also warming an annex etc. ASHP running for very long periods can be unnerving but it's what they do, you need to run them long and low!

Could you/I would wrap a few layers of Armaflex tape around the form of it to seperate screed from stairs? Few mm will help provide a degree of seperation, will help reduce the problem of it. Use thicker underlay for your flooring. Wood as you plan for, with a carpet runner maybe? (I don't like wood stairs, with the wrong socks on far too slippy) Reality is you're gunna have to suck it up and move on, else face serious serious cost, headache and heartache trying to fix when EVERYONE will roll their eyes and think you're OCD. The £canceled screed alone cost will be worth more then 10 years of that thermal bridging, let alone piss off factor, delays and cost for whatever bodges you try and introduce to fix. You can't win them all! Building houses is not a zero sum game. Just double down efforts elsewhere to try and offset it, move on and forget about it. Edit.. Damp won't come up as the block and beam has dpc and is ventilated to keep it dry anyway.

What research did you do into ASHP and it's applicability to you? How did you come across the need for one? Are you on mains gas? DHW is an instant odd one, ours currently heats ours to 50degs, and can do nearly 55 degrees. Yours should be able to do the same. Do you have UFH? Did you over size the radiators? Your heat loss is pretty average for a newish buildin the last 10/20 years and isn't the worst I've seen, but it won't be cheaper to run then other sources of heating... I wouldn't expect it to be ruinous to run though. How warm do you like the house? Also, what's your actual usage of the ASHP? "powering external units" clouds the information you're providing.

Sorry OP, that's a pretty basic thing to have gotten wrong! You need to weigh up the cost to rectify back to what you had permission for vs time, money and effort vs fighting it. Probably win in the long term if you can show what you've built is in keeping with existing design principles in your immediate area. Porch may be tricky if it's in front of a building line or equiv. How much bigger did you make it? I'd probably look at finding a local planning consultant in your immediate area to advise on the potential of a successful appeal, and pull something together! I could imagine being on the back foot for

Heatmiser, it's a good one but we have over zoned it..... But nothing plaster and paint can't fix if it does prove to be an issue... Which for now it isn't!

Does everything have a U bend? Your picture implies they all do? If virtually no fall, and regular use with soap etc it will gunk up. I presume you have a very shallow distance to enable a proper fall to be installed? Could surface mount a proper soil pipe and box in? Create a low shelf, tile it in etc

We used 25 to 50mm PIR with expanding foam to fill in the gaps!

I would be wary of one potential awkward tenant ruining it for all. One tenant having a full, hot bath in the morning or evening.... would deplete a large portion of that 300L. And/or several hot showers in the morning or evening emptying it again. Broadband... A couple of people downloading torrents etc can have an impact if everyone else is watching Netflix or gaming. That hot water situation would be a concern though, as could be a massive headache as people will NOT be quiet about semi regular cold showers which they can't control, predict or plan around.

Don't forget the context before you fall out of love for your house. Buildhub is here for the extreme high end of the market, so your scores are not great to this forums standards, but that's still a better score then 90% of homes on the market, and all the savings you mentioned might save you £15-20 month. Top up loft insulation, and some additional detailing around the edges will get you an extra a few% few average UK home. I imagine your heating bills anyway won't be much more then £150 a month?

Could they Rockwool behind, timber battern in, fire rated expanding foam sealing it all in tight, then plasterboard over the top?

As has been said, use this storm to inspect how damp the walls get. Generally you get it rendered down to 2 engineered blocks, which is where DPC is. I'd be tempted to use this storm and the damp near ground level to get the render trimmed back up. Not a great pic, but you can see where my dpc as the render stops, I have raised beds/driveway etc to go in yet!

I think you'll struggle with something so rigid. Rockwool will at least scrunch up and can be torn up and stuffed in!

Have you got any pics of before installation? Or during construction?