Nickfromwales

22mm backbone is fine if there’s a hot return. Otherwise, just painfully slow to get hot water from basin taps. Avoid.

Totally. For woodcrete I’d get them in before you have boarded, as that will allow you maximum exposure for the magic goop to do its thing. Follow on trades will all need inductions and in agreement to maintain the integrity of that airtight layer. On an Isotex job the client tried a liquid membrane, spray and brush applied, but the woodcrete simply has too open a pore for this to work well on bare woodcrete. Another parged first and got 0.66ACH, but neither were ‘cost effective’ (they were expensive as feck). AB is your friend here, but obvs a certain amount of prep needs doing ahead of their arrival.

But……would the pipes not move also?

That’s good to hear. They are doing it correctly. 👍

As you’ve gone for woodcrete, I would tell you with my last breath, to get AeroBarrier in to get you airtight. Leave all the parge coating etc and just let the magic happen. You’ll thank me later.

It took a loooong time to get there, but yes, in a nutshell. lol. 🥳👍

Cheap and quick sanity check. Best to start the process of elimination there as it sounds like that’s defo the choke point.

That’ll work. If it’s 50 a lot, or high 40’s you’ll maybe find it a bit too warm. Perhaps reduce the quantity of pipe to just a squiggle where you’ll be standing when towelling off etc.

This is getting out of hand lol. There’s is zero chance of pulling all these hypothetical cables, from and to those hypothetical locations, without a padsaw, a hammer, a hole cutter, and shares in Toupret (cos you’ll need a lot of filler). Conduit is the only semi-feasible option, to every box, to a central location. Barmy. Sorry.

To answer your original question, you need to work from the invert of the sewer back to the house, unless you're on a STP?

Yup. Defo a curious one. So boiler fires up, heat gets to the mixing valve (defo on the flow pipe?), manifold pump is pumping, but no heat getting into the pipes. Can you try operating the zone valve manually, when this is running, and push the lever across so see if there's no resistance (eg that the ZV has fully opened, mechanically).

At what temp?

Pump spinning freely?

Gypsum ones may have issues with adhesion, so triple check those before attempting to stick tiles down. Cement based T&G boards should work well, but I’m always sceptical as these are brittle and are entirely reliant on the joists being straight etc. Wood bends and conforms, so I just prefer that method. Done plenty with alu spreaders under P5 + plywood + tiles. Works well, but needs higher temps than UFH in screed, so some jobs have needed a separate manifold for the FF bathrooms.

I always use 22mm P5, and then use the plywood as a binder; staggered joints and glued & screwed. P5 for strength, and ply as bulking material and a binder. Never had a floor crack so that’s my preferred method.

When you take the white control (TRV) head off, does the pin push in and release back out freely?

I’ve painted a load of new kitchens, on new plaster, with the (cheap?) trade Matt Leyland stuff, no MVHR in a lot of the older jobs, and zero issues whatsoever. It is very chalky, so you can’t scrub it, but I can’t remember the last time anyone scrubbed their kitchen ceiling vs just painting it again. Diamond on the walls is very good, but a pig to sand / key for subsequent coats.

I use PVA with a 3mm notched scraper on the P5, and lay the ply down onto that whilst wet. Then screw the ply down with 4.0 x 25mm screws at 100-120mm centres max.

Geordies and Maccums scrapping it out on the ships all day was entertaining lol. My chargehand was a Sunderland lad.

Yup. I use Leyland Trade Matt White (high opacity) for all new plaster work on all my jobs, where we’ve taken the job to a finished article. No mist coat or faffing about, just out of the tub, on to the ceiling / wall, and if we got that on by late morning you could second coat the room the same day. Very few people asked for a 3rd coat as it just builds ridiculously well. Looks like shite until it’s bone dry, 24/48 hrs after the 2nd coat, and then you’ll swear it’s had 4 coats. @Spinny go for the Johnstones tinted as required, but beware any sanding or priming as you’ll need it to be applied perfectly to not see that you’ve applied it. You obvs need to take steps forward, vs sideways or backwards. Defo do NOT use the diamond Matt on the ceiling.

@Super_Paulie I just noticed that you come from a dodgy area. I worked in A&P Tyne for years, both Hebburn and Wallsend, on RFA contracts. All hail the stotty! Many a curry consumed down Whitley Bay.

You select this to your advantage, to balance floor levels from room to room, sir. 6mm is plenty, just make sure to glue and screw it down to the P5, and you will be triumphant.

Thinking you’re going to be able to add cables , retrospectively, is a little optimistic; myself, I think it’s practically unachievable. You’d be into breaking in / out of plasterwork, going up / down walls filled with (supposed to be filled with) acoustic insulation, and other services. It’s just way to hard to plan what’ll need to go in, and from where, and to where its “then” needed, to be a realistic approach. You’d need a complete redundant conduit network left in abeyance, throughout the dwelling, to ever attempt to mitigate this sensibly.

I pay >£1.8k for a decent (PH certifiable) MVHR unit, or more if it’s above 300/325 size.

Thanks for the suggestion. I’ve made it so!