Nickfromwales

Or you get another builder. Purpose of a VAT man (a qualified VAT advisor) is to give you advice covered by a professional indemnity, which you can reply on, vs random info on an internet forum which is essentially worth its weight in sausage meat. . With such a potential cash saving I’d not want it left to chance or for there to be even 1% ambiguity.

Apologies for the digression. So, I see the b&b flush to the top of ICF, and then in the background I see the opening for the doors / sliders(?), so what is the allowance for PIR over the b&b with an 75/80mm screed?

The step doesn’t want to be on the insulation and screed. Good advice above, but I’d do a second stack of TL blocks to create both steps. Would be good to get a bit of Marmox in front of the blocks of the steps, where the screed hits it, as they’re technically ’cold’. These are marked in green. 15mm will suffice there as they won’t be worlds apart temp wise.

210L of water isn’t much, assuming this is indoor? Is the tub insulated? I think the option to heat from the EAHP UVC via heat exchangers would drive the HP in the cylinder very hard indeed, and perhaps have an adverse effect on its longevity, for one, but also when you factor in the inefficiency of the PHE converting heat then it adds up against it further. Running the tub as a buffer would mean having it heated all the time you are running UFH, so you’d need to insulate it and deal with evaporation losses as humidity too, if kept above the ambient room temps. Likely you’d need dehumidification then too.

Yup. Just re read this when not tired and ‘multi-tasking’…. Defo don’t put type 1 under it, needs to be type 3 clean stone without fines, and free draining. Time for a new SE? 1st year apprentice stuff emerging here. @zzPaulzz let me know if you want someone (SE) who does Kore etc in his sleep and can give you a quick turnaround….

The “reinforced concrete ring beam” needs to be subterranean, with the bricks disappearing into the landscape. You can’t have the top of that concrete exposed at finished outdoor landscape level…. That obvs doesn’t need as significant an amount of EPS under it, assuming it’s only carrying a few courses of bricks(?), unlike the amount shown under the ring beam, so dropping it will have little effect ‘structurally’. That shouldn’t be a major issue to amend, but another oversight is that the EPS defo needs to encompass the RCRB to stop it rolling / migrating outwards, eg it should be ‘sat’ in a kind of EPS recess (channel) vs sat on a shelf of EPS. The compacted layers outboard of the foundation should be pushing back against the EPS in front of the RCRB, vs directly onto the front of the RCRB. Not great currently! It’s wrong in a few ways as-is for sure, so add those points to the growing list of immediately obvious faux pas….

I think the UFH might struggle to get adequate flow when the rads are open path and flowing freely, as the pump potential will always choose the path of least resistance. The UFH loop smallest / shortest will get nice and warm, but the longest one will likely perform less admirably. If you can make all the UFH loops hydraulically similar then it may work, but any time the rads are all open, flow to the floor will take second place. Are you very sure the design is sympathetic to one flow temp from source? If so, I think a pump on the manifold would be wise, but obvs minus the TMV. With the second manifold pump, it will circulate the loops, vs pump flow and return to the manifold, so there will be hydraulic separation. The flow and return from the boiler & its pump would tee into that via 2 close coupled T’s, so the 2 pumps never conflict with each other.

You could give Andrew Jones aka “The VAT man” a call and get some actual, dedicated advice about this. Best to find out everything you can claim etc in case random info on the net falls short and you miss out? Plus he’s Welsh so must be good 🤷‍♂️😀. lol. Mention my name and the forum and he’ll look after you 👍.

Yup. And nope, not on that job as it wasn’t necessary.

These were all short runs, kitchen and utility very close, most bathrooms directly above, so no hot return required. Furthest basin was piped in 10mm and was less than 5-6 secs to get premium temp hot water out of the tap. Far right manifold was 4x wash basins and if you follow the pipe work back you’ll see it is fed via a TMV to cap the max temp at the basins.

Nope. Radial runs from the hot water cylinder vs series run (which is what you have which sucks lol). So each hot and each cold has its own pipe from a hot or cold manifold at the cylinder.

Thermostatic mixing valve.

I do the showers, baths, and (if they’re less than 12m away) the kitchen and utility hot feeds all in 15mm on radials without the HRC feature. I then fit a second manifold via a TMV, which feeds to all wash basins ONLY, on 10mm flow (<12m) or 15mm flow (>12m) and always on 10mm returns to the HRC pump. This means the recirculated water is never over 46°c, so you can use Hepworth (without voiding their warranty) and the dT is much lower than sending 50-55° DHW direct off the primary UVC TMV, thus reducing losses to the point it’s not worth crying about; but obvs the pipes are all insulated too! An HRC is a brilliant luxury I would afford myself in a heartbeat, especially if I had solar PV > UVC all summer and an ASHP for cheap as chips DHW in the first place. Defo include!

Heat direct with a small pool ASHP is a no brainer here, get a little portable outdoor unit and plug n play? or simpler again is: for change of £200, but direct electricity.

Top up or heat back up from ambient (cold)? Big difference, so how would heat be preserved to make you say top it up daily vs heat it daily? What’s the target temp of the then heated tub water?

DIY’ing then? Probably better to discuss that on a new thread lol. Just trying to get an overview so heat loss and UFH picture is clearer. On that note, a full floor plan would help

FWIW, I prefer option 1 vs option 2, but with the DPC both meeting and lapping over, comes the challenge of bonding the mortar / adhesive beds under / over the plastic DPC. The other option would be to use a liquid DPM/C to separate at the mortar / adhesive joint.

You can’t have the DPC up that high and under the tiles as they need to be bonded to the substrate with flexible tile adhesive. That needs to be dropped down under that upper block. Also, you won’t be able to tile that vertical PIR, so that’ll need swapping out to Marmox and you’ll need to set that back against the vertical sections with flexible tile adhesive.

Oh and yes, defo sister new timbers both sides of every joist, extending as far under the preserved sections and perimeter as you practically can. Weight will not be a problem at the perimeter and sink, just focus on the shower area and WC.

Jesus. That’s shocking. I used to love destroying insurance companies, all you had to do there was say you fell over and the impact broke the floor. Automatically gets the claim through under ‘accidental damage’. May as well just get stuck into it and rip the lot up, it’s near total loss. To minimise grief / time, cut around the tiles nearest to the sink and WC and perimeter, on the nearest grout lines, slide more 4x2’s up under the sink and WC to reinforce those point loads with screws and D4 glue, repair all flooring into shower area, and P5 board the lot flush to the edges of the tiles / perimeter you’ve preserved at outer walls and WC / sink. Get a mineral floor laid over latex (to get the falls) and that’s a quick way out of this.

Hi, and welcome aboard 🫡. There’s threads on here from a chap who was a hutter, @Tennentslager Have a read of his adventures here as a start point 👍.

So you'll be having MVHR also?

OK. You keep saying "commission", do you need to commission it or just turn it on to get heat? Big difference, as one makes sense and the other doesn't Some folk have their tilers recommend thermally 'shocking' a newly laid slab / raft foundation to provoke it into hairline cracking ahead of tiling, but it depends on if it's a screed, a slab / raft, and how long this has had to dry. So do you just want heat?

We can help here tbh, what's the heat source? ASHP I assume? Any quotes or spec in for that yet?

Explain please, so we can advise best without kicking the can too much.