Thorfun

I decided against one to start with as our toilets are flushed from the RWH tank so that shouldn’t affect showers etc. I guess if I find we have pressure issues we can fit one at a later date.

There’s not enough room to bend the plastic pipe out within the stud walls. I’m ok with having a fitting behind the wall at each appliance/sink/basin etc. I have no other joins from plant room to tap so my risk of leaks is greatly reduced. And if there ever is a leak I know where it’ll be.

it's a hang on the wall sink but we're putting a unit of sorts underneath.

not had a biscuit since you threw your toys out of the pram a little while ago. tbh, I don't know the benefit! nor do I know the downside. both copper and hep2o can be dismounted if required so I don't see the difference. only thing I can think of is that copper comes out of the wall straight but it's hard to get plastic to be nice and straight? maybe @Nickfromwales or someone else who actually knows what they're doing can answer your question.

I need to 90° out of the wall so converting to copper is easy as I can push fit it into the 90° hep2o elbow. I don't see the issue here! I see most posts that people come out of the wall in copper and run plastic in the walls. 🤷‍♂️

that's the HRC. if you can tell me how to make that connection NOT inside the wall without having a load of connections under the sink then I'm all ears! I did think about the potential risk of making that connection behind the wall and then figured I'm already putting 90° elbow bends behind the wall to bring the hep2o out so there's already a risk behind the wall. to make that HRC connection outside of the wall I'll have to bring the 15mm hot and the 10mm HRC out through the wall via 90° elbows and then join with the reducing T. all sounds rather messy.

small black pipe is condensate pipe from an AC unit. 18mm ply fitted within the studs for fitting the basin to. that's also on tomorrow's list of things to do!

decided to stick with 32mm as suggested by @joe90 and given the go-ahead by @Nickfromwales! this is my first attempt at a basin waste and pipework and this room will be boarded Monday so if anyone can see any issues then please tell me now! I wasn't sure where to bring the copper out for the taps but there'll be a cupboard under the sink eventually so figured it didn't really matter? on to the toilet waste as toilet water pipe tomorrow.

Sure can! It’s a great way to save money. if anyone questions it just call it landscaping.

Problem is it’s a very small room already and losing an extra 18mm will make a difference. I could add the ply between the studs though so as to not lose any room size.

But how will taking nearly 50% of the timber width affect the structure of the wall? That’s my concern.

next question which is related to the previous discussion on upsizing waste pipe. i know that @Nickfromwales is a big advocate of doing this, so for a wc basin the waste pipe would be upsized from 32mm to 40mm. but in our downstairs WC i will have to drill holes through the internal stud wall to run the waste pipe. it is 89mm CLS and so if i'm drilling a 45mm hole (to account for the fall of the pipe) through the 89mm CLS that's quite a fair chunk of the timber missing! is this an issue? should i just stick with 32mm in this situation? the waste run is about 1m at most from basin to soil stack.

our target was 1ACH. our house is much more complicated that a basic rectangle and we spent a lot of time taping windows and membrane around attic trusses and fitting Tony trays etc. we ended up with a score of 0.98ACH@50Pa and were very happy. we know we could've got it lower if we had the time (and a diy blower to keep testing with) but as we'd already hit my target i was happy to leave it there. so 1ACH is very achievable doing it DIY.

is your house actually being run on all 3 phases? we have a 3-phase supply but i decided to reduce complexity to just run the house on a single phase and run 3-phase cable to the garage where the EV chargers will be just in case i decide to go 3-phase charging. Our PV is run off a single 10kW Single phase inverter (the same phase that the house runs on) again to reduce complexity and our battery storage is also on that same phase. IF i ever need 3-phase then by that time hopefully 3-phase smart meters will be more readily available and it can be configured for net metering as @joth mentions above and then it doesn't matter if i draw on the 2 phases that don't have PV on them as any excess generated that is sent to the grid will offset any draw from the grid on the other 2 phases.

this subject has been debated quite a bit on here and i don't think there is a perfect solution! you could absolutely go overboard with insulation, resilient bars, soundbloc etc but then you need a gap at the bottom of the door to let air in/out for the MVHR! so sound will escape that way. in the end we decided to use resilient bars in certain places where we wanted to reduce the sound transfer, e.g between my study and the kid's bedroom above and we used 100mm Rockwool in the ceilings between the joists and 50mm on internal walls. we haven't used soundbloc anywhere and are using 12.5mm standard plasterboard. was that a good choice? ask me again once we've actually finished building and have lived there for a while! my conclusion was that we'd never eliminate the transfer of sound without spending a lot of money and detailing every wall to ceiling to floor junction with sound sealant etc so we just tried to take the edge of it all.

we filled our 89mm studs with 50mm Rockwool as well. no issues with the cabling that our sparky mentioned. I presume it's because the cables are running in the insulation but rather sat on top like this photo but maybe @ProDave can give a definitive answer?

Seriously? Why bother? Save your time and money!! It’s already insulated and airtight to passive house standards. Any additional insulation will give very little gain I would’ve thought. Plus you’ll likely have to uprate your electrical cables as they’ll be running through insulation.

Yeah. For the bathrooms will only be part plastered as a lot of those are tiled. But the WC is so small it’ll be trivial to just do the whole thing. But I’ll ask if there’s a cost implication and make a judgement call. As @Pocster says, I am a penny pincher! 😂

SWMBO wants a part tiled WC. And she gets what she wants. The clue is in the title SWMBO.

My plastering is shit. The end.

Cheers @nod. Will just use standard PB and get them to skim the whole thing. Will just be easier that way I think.

ps. if it's ok to tile on to plaster would it just be easier to get the plasterer to skim the whole room rather than stopping at 1200mm above FFL? it's a small room and wouldn't take long to just do the whole room!

hi all. I've done a quick search and pretty much all the threads about tiling on tile backer board or plasterboard or cement board etc seem to be about a bathroom/shower area. But in a downstairs loo that will be part tiled to about 1200mm high and then painted the rest what is the best board to use? is standard 12.5mm plasterboard ok? it seems possible for the tiler to use a primer to tile directly on to the plasterboard and the plasterer can skim from 1200mm and up. but is there a better way? also, how accurate does the plasterer need to be to the level of where the tiles will be? if they go a bit below the line is it ok for the tiler to tile on to the bit of plaster or will that need to be taken off? I'm sure these are all beginner questions but, in most things, I am still a beginner despite being 2.5 years in to our build!

I decided to redo it. in the end I only had to cut one piece a bit shorter and that gave me a better angle of descent. I'm now at 1:40 which I'm much happier with! I'm glad I did it as well as when I removed the horizontal piece there was a bit of water still in it. so it was definitely worth it in the end.

Sadly have too much to do! Need to build a stud wall to block this work in so it can be boarded and plastered next week. No rest for the self-builder!