Nickfromwales

4mm2 earth cable was retired a good few years ago, so I fear you’re quite unprepared for this. Please consult a sparky, as the fuse-board aka CU (consumer unit) is very likely in need of an upgrade to make this safe for your little bundle of joy

It’s so much easier to knock a door, with a bottle of wine in hand, and ask how the best way forwards can be achieved. Builder needs a lesson in how to act professionally and courteously, so sounds like he’s used to being somewhat of a bully, sadly. I’d just go and knock their door, and have a normal, regular conversation with them, which will give you an opportunity to explain your prior objections, and the way the builder has spoken to you, I think you must accept the inevitable, and not lose any more sleep. Go talk to them

Shame they couldn’t use a spirit level when setting the ceiling out….

There’s so much velocity with rain / storm water, these things just tend to flush themselves out. Last one had private BCO and warranty by the same company, and they didn’t want / ask for rodding on rainwater. If you choose wisely, the rainwater gulleys can come with a blank access plug, so it maintains a trap but gives rodding access to the pipework. Decent jetters can get around pretty much anything tbh.

Pretty much, unless it’s a cathedral. Temporary tiled displays can go onto decoupling membranes that are floating over the substrate, some I have done exactly like this over floating floors in apartment blocks where the floors are mechanically disconnected by design, for acoustic control. Sounds doomed to fail, but worked perfectly well tbh.

Work out the sizes you need, go to a merchant, and cut up an 8x4 in their yard.

Filler panel to match the wardrobe doors, scribed in to the coving. I never have the coving finish to the panel as it’s a pig to install ‘in reverse’ plus then it can be installed /removed easily.

My PH certified designer is Ok with 1000mm separation, so ergo, I am also good with that; or anything more as a bonus. I feel your pain. Currently on site retrofitting a whole of house MVHR system into a converted 3 storey, brick built Victorian semi….. Done more carpentry and joinery than MVHR work here tbh!! 🥵

£2k for peace of mind and absolute insurance against failure for 200m2 of floor, is not really a “big” cost, considering the project as a whole? Think of the cost and inconvenience of this having been omitted, but necessary, and you're down to a part of 1%, not even a whole. 49%, eg at ‘50% doubt’ I’d be decoupling.

Rockwool fill, 40mm PIR, foil tape, then PB. You’ll need to manage the holes for lighting, or use a surface mount / pendant.

1300mm is plenty, you’d be ok at 1000mm tbh; if you're happy to receive ‘real world’ advice In-wall is fine, done this plenty of times, just a bit less ‘aesthetically pleasing’ to some. How so tricky? Have you not got posi joists?

The thinner the screed, the more likelihood of fractures (slight cracks) which over time could translate to visible failures of the tiles or grout. If it’s 40mm of fibre impregnated, cementitious liquid screed then you’re at the 49% club, if its 40mm of dry screed you’re in the 80-90% club; dry screed does not like going down as thin as 40mm, but you mention ‘poured’ so I’m assuming liquid screed? Then, if it’s gypsum vs cementitious, at 40mm this would have a reasonably high risk of cracks vs fractures imo, so I’d decouple as I can’t take any risks with clients projects. I’m also considering the repeated thinning out where the (?)16mm UFH pipes lay, reducing thickness to 24mm, linear to the whole length of each pipe run. That’s a significant, further compromise when looking at this holistically. If it’s fibrous, cementitious screed, then I think you’ll get away with having just a good quality flexible tile adhesive, with a min 6mm bed, laid over an appropriate primer (with the tiles being laid onto the primer when it’s wet). BAL do a tile adhesive that has (x)mm of decoupling qualities, like an ‘ultra-flexible’ adhesive. I always Ultra (Insta) products, never had an issue. Are you actually using ceramic tiles? These are quite feeble compared to porcelain, so with ceramic and the very thin screed I’d be saying 100% you should decouple. Points B,C,D, and E are all moot.

The only concern is 40mm of screed is as thin as it gets. That is the only reason I would suggest decoupling here.

And they deliver. Been using the one down the road for 20+ years, always great price / value, and stuff is usually in stock.

Is it cool in summer?

Yup. A pita to get a fitting on to, circa 20mm o/s dia iirc.

Why not use EPS instead of the RFG?

Draw some samples and get them to a laboratory!

You princess lol 🤣

Guilty as charged lol. The rubber bungs are very good, and have never caused me any issues, and I have used them for as long as I can remember. I would switch to 1x 50mm pipe / bung, and then T off in the cupboard for the two connections. I bring the 50mm pipe vertically into the bottom of the unit, then install a Y branch. Into the branch I install a 50mm cleaning eye (this will provide adequate rodding access to the 110mm pipe) and use the top of the branch for accepting waste water from the sink and appliances.

Expensive and laborious option? What’s the rationale for using foamglass? You can ‘plumb as you go’ and even have just one loop filled and working, as the manifold will allow you to shut off the ports for the future loops.

Sounds like grey water stink vs SVP “stench”. FWIW, the only smell that makes me being my lunch immediately back up, is when cutting ancient, blocked kitchen sink waste pipes out; the black sludge is just horrific, compared to a whiff of 💩. Do you have a pic of the plumbing?

Is there any known insulation under the existing floors, and what’s proposed for the extension floor? You’ll likely need to put pipe in at 100mm cc on the existing areas, and maybe 150-200mm cc for the extension, to balance out the difference in performance. Running the pipes in to Z2 is easy, just needs some sleeving over them where they exit the room, but why not have the manifold in the back of a kitchen unit?

Stench of sewerage? Is it coming back through the dishwasher?

https://amzn.eu/d/0ejwJXIa Lose the rigid one, and use the above to give you enough wiggle room to get these pointing vertically again.