PeterW

@Onoff Same product. The CB one is an own brand badged version of the one @AnonymousBosch linked.

@AnonymousBosch that is one, I prefer T+2 Rectorseal

Always go 22mm to a heat source - 28mm is even better for long runs however you may need to check the heat pump connections. I know the last couple I’ve seen have 1” or G1 connections so 1” to 28mm is possible but looking inside the units the pipework to the heat exchangers are only 15mm.

Bare render, 5:1 paint to water according to Dulux. Nothing else needed.

Do not use emulsion !!! It will come straight back off. MIs - Manufacturers Instructions - on Dulux exterior weathershield are to do as I said. One coat at 5:1 paint to water then top coat with full strength.

Not sure it needs a base coat, just two coats of standard paint Just checked and MIs are one coat done at 1 part water and 5 parts paint, then one full coat over.

@Taff you will struggle to get 45c from an ASHP - 35c is your target temperature and they should factor that into the design. What is the ground floor / first floor construction ..?

@Taff What is supplying the heat to the system ..??? Just seen it says supply temp of 45c, and that means gas or oil. I would seriously question if they have used a standard set of details or your build spec - that looks like a big heat loss to counter and 45c flow in a timber floor (??) upstairs is going to be hot.

There are far too many thermostats in that design ..! Only works when all doors are closed and no air flow between rooms. I would reduce down to having one upstairs and one downstairs with the en-suite / bathrooms potentially on their own circuits just so you can run them for longer or slightly warmer.

I have and I do, and also have copies of the British Standards and other references to hand - what I have quoted (and apologies) is the PassivHaus minimum ACH calculation on boost, which is used as a background check for ensuring air quality.

That is not correct. The full guidance requires you to perform a minimum check to ensure 0.3 air changes/hour will be achieved. This is calculated by multiplying the total Treated Floor Area (TFA) in m2 by a ceiling height to establish the ventilated volume and then multiplying this figure by 0.3ach and 1.3 (Floor area with less than 1m ceiling height is ignored)

Your concrete slab will take 6 months or more to cure and will continue to give off water vapour too. If you put a piece of heavy plastic on the floor about a foot square, cover it with an offcut of PIR and leave it a day and you’ll come back to a damp patch under the plastic. Big industrial dehumidifier from a tool hire place will dry stuff out in a week or two, and they make it a bit warmer too.

Get the steels drilled with 16mm holes in the bottom web, half the distance / thickness of your walls (ie if they are 140mm studs then holes need to be at 70mm) Then use M10 coach screws with washers through the holes into the top of the timber. If you can get all the way through - such as the timber being less than 100mm thick, then use coach bolts. Don’t crank them up tight, but enough to nip them up.

So it’s definitely a solid concrete floor now ..? And you’re happy that you can go upward on door frames ..?? Get the 150mm additional clearance ..?

No he just keeps drawing options with screed - you don’t need to use it ..! There are loads of wet floor overlay options - if I get chance I’ll ring Wunda tomorrow and speak to Andy and see what he suggests. Other option is the Fermacell floor system over the track panels. Again, not cheap but works well.

He’s got a thing about screed..! Electric UFH can cause issues with LVT so it is not something I would use. To use the Wundatherm system for LVT or Karndean you use Duo boards over the top - not cheap but works fine.

Yep it’s called an Armeg DL100B4IG SDS Plus Drive Adaptor for Square Cutter Amazon, £10

we used to do this but direct the “blast” into a galvanised dustbin laid on its side ..... Swear to god I’ve heard less noise from a 105mm field gun ...

It’s a Scottish thing ... Not required south of the border.

I would drop the T down to floor level and replace with a Y fitting and a 45 degree elbow to bring you level.

Dig a bit further down, and then a bucket of hot water over the top to clean it off but that will be a clay pipe. The hole will need to be bigger - half as much again along its length. The simple way to remove is to take a whole section out - start from the middle and work to the joints. Then use Clay adapters to insert some PVC pipe with a standard Y connector. The new stack will go into the Y branch, when you remove the old WC, seal the pipe off with a cap (unless the WC room is going to become something that needs a drain ..??)

TW50 has a slightly lower compressive strength than TW50 and Thermafloor but other than that there is little difference. It is 125 vs 140 but not exactly a lot when you consider EPS70 is ... 70..! So PIR is half as compressible as PIR

I can confirm that distance and damage seem to be linked with some of their deliveries. I have had two deliveries from them, both in about the 35 mile radius, and they were fine. One of the deliveries was missing a plinth but otherwise it was ok. I know of a couple of deliveries where they were 120 miles or so, and had increased damage. The reason seemed to be that they were part of a bigger set of deliveries and it was the unloading / repacking of the vehicle when the first or second delivery was removed that may have caused issues. They can have up to 5 or 6 on a vehicle so this is probably more down to the delivery crews and packaging than the product leaving the warehouse. I am surprised the driver told you to call as they are clear that if you need spares or to report damage, then you need to do via web as it gets it quickly into the system. They use it to route priority tickets into their production planning system and I’ve also had stuff put into prod that has been made when I’ve been driving to the factory to collect it. I do though think they may be a victim of their own success ...

Have a look at this video for LVT These are the boards https://www.wundatrade.co.uk/product-category/home/overfloor-retro-fit-solutions/wundatherm-underfloor-heating-boards/

PIR has a large point load capability but I expect here the screed was too thin. Any info on the screed depth..??