MortarThePoint

I'm starting to lean in that direction. 4no. direct pipes to taps would have 8 joints (4 at manifold, 4 at taps) where as 1 pipe branching at a sub manifold would have 10 joints (1 at main manifold, 5 at sub manifold and 4 at taps). If each joint is a worry, I 'only' increase the worry by 25% but massively reducing the routing headaches. If I'm worried enough, I could always put the sub manifold into some form of draining sump. Their plastic manifolds are all 22mm in though and only up to 3no. 15mm out.

Perfect, thank you. Looks like 40mm spacing.

I don't know unfortunately as the link is broken 🙂

I've worked out that if I have all my outlets as independent runs from the utility cupboard, I'd have 31 runs (12no. 10mm and 19no. 15mm). It would use 108m of 10mm and 132m of 15mm and no additional fittings vs 34m of 10mm and 108mm of 15mm with a dozen or more fittings. The extra cost at the manifold likely wipes out the saving on fittings, but means if I have a leak it will most likely be either at the manifold or at the outlet itself. It would involve passing 26 pipes through a blockwork wall though, rather than just 12 pipes. I haven't made provision for this, so is the simplest thing to do to core drill larger holes, passing multiple pipes through each? The cold ones would need to pass 15 pipes. Whilst that could all fit through a 70mm core drilled hole, that would be a nightmare to route or make any future changes. Below shows that you can fit 4no. 15mm pipes or 7no. 10mm pipes through a 40mm core drilled hole. Using a 50mm core drill should make it easier and might allow the holes to be lined. I'd want a good gap between the holes to ensure each behaves structurally as a single hole, guessing 100mm would do that. I'd end up with 6 such holes, spread over about a metre. Does anyone know the spacing of the outlets on the brass manifolds?

How should I deal with the junction between plasterboard and screed? I know normally you raise plasterboard up but that leaves a gap for tanking. Can you recommend something to fill the gap with in the shower area as would be good if there is something waterproof. Or do you have the plasterboard come all the way down to screed?

Top tip for Acoustic studs, use a different brand of screw. When inspecting a wall after the fact, if you've used a different branded screw with a logo on its head (e.g. Dewalt has DF on) or a BZP screw like the Screwfix ones it is then easy to inspect. The screws mustn't be too long (e.g. you want 25mm with a 15mm plasterboard) so if you only have 25mm screws of that type it's easy to check the correct screw has been used. https://www.screwfix.com/p/easydrive-bzp-bugle-head-fine-thread-uncollated-drywall-screws-3-5-x-25mm-1000-pack/25899

I like the idea of having completely separate loo feeds (10mm?) Which go all the way back to the manifold. Makes swapping to harvested water easy. Additional pipe and clips probably adds £50. Water is about £1/m3 and 20 flushes per day would work out as around 10p/day, so £37/yr. May make sense. Any harvesting method wouldn't have zero annual cost though.

I know, it's a staple of modern building. It's to do with indoor air quality and VOCs. I don't think it's really an issue but we've started down that road now so need to see it through

How about a 50mm pipe clip having padded the pipe with UFH perimeter insulation or some other padded tape. I'm avoiding using spray foam in the airtightness envelope (I know, it's a pain).

Aren't CLS and Regularised both eased edge? Why does Chippie prefer the CLS? Is it because it's lighter? Or is CLS typically straighter? Spot whose not a TF expert 🙂

Brilliant, I'm feeling a lot more optimistic now. Thank you!

Should I use a tape like the one below at the blockwork / plasterboard junction, or will I need something more flexible? https://www.amazon.co.uk/Everbuild-Aquaseal-Waterproof-Tanking-Tape/dp/B0086FC8S8

Cool thanks

Thanks, Can you think of any product names, or is it the same stuff as the plasterboard tanking kits?

I have mixture of two substrates for my shower walls. One shower is 1 side MR plasterboard and 1 side blockwork, another shower is 2 sides MR plasterboard and 1 side blockwork and the last is 2 sides blockwork. I know the 'easy way' of doing is to use a foam board like Jackoboard/Abacus Elements/Marmox/... but we're not using any foam products inside the airtight envelope. Why we are doing that is a different debate and once we've started down the road backing out undoes all the sacrifices made up to now. It's very hard as building today without spray foam is hard to do. This also precludes foam tile backer boards like those mentioned. I know you can get tanking kits to tank plasterboard and make it suitably watertight for a shower, but what about the blockwork?

I can understand that. Murders the timeline though

Attached are the dimensions sheets that Mira emailed me, converted to images

Just went to City plumbing and they said would be spot on but was slightly over 1210mm. That was the with up stand type (see pic below), which may be slightly larger. The guys in the store were genuinely surprised when they saw what I measured. This was a 4 sided up stand Mira Flight 1200mm x 800mm.

Thanks, I had wondered about that. It's very snug where it passed through the studs (in fact concerned it may squeak due to thermal expansion) but clips would be good I agree.

@Nickfromwales this is what I've ended up with. The cutouts are only slightly larger than the pipe so no real way to isolate. I've used rubber edge strip which will hopefully help. I'll be putting some Kilmat on the pipe and filling wall with Acoustic Partition Roll.

Thanks nod, good to hear it is used. There's a lot to be said for following the standard recipe. I can appreciate a sealant could help air leakage, but am doubtful about the sound. Sound can't leak through small gaps like air does due to diffraction. Think of your microwave door with its mesh. Perhaps it helps by acoustic coupling the frame to the background.

BG show this used all over the place. They recommend it is used around the edge of metal frame, so between frame edge and wall, floor or ceiling soffit (couple of examples below). I'm a bit dubious as you're then putting plasterboard over the top and skimming or taping and jointing which ultimately adds far more material. Am I missing something, or are BG just trying to get more of the value chain? They say it "Boosts acoustic performance by sealing gaps". If it is worth putting something there, why not just use caulk or something similar/cheap (Gyproc Sealant >£12/tube, caulk ~£1/tube). I often find I phone up merchants trying to buy parts of a 'system' that it turns out nobody actually bothers with. https://www.british-gypsum.com/products/finishing-products/gyproc-sealant https://www.gyproc.ie/knowledge-centre/cad-drawings

It was my plan to get the walls up this weekend 🙂 Change of plan time

1200mm x 800mm reasonably low. Not too fussy about style but needs yo be white or very light grey, but the waste needs to be in the middle of the short end or in the corner shown below. Something like : https://www.screwfix.com/p/mira-flight-low-rectangular-shower-tray-white-1200-x-800-x-40mm/1906x

That was my fear. Is there anywhere you can think of with shower trays on the shelf? Would be good to unblock progress