Onoff

In section I imagine the edpm in effect comes along horizontal then turns through 90deg up the side of the upstand. I'd be particularly cautious / worried about driving on the paving close to that upturn's internal corner and splitting it.

It's 32mm pipe. An earlier thread discusses a bit more here: I have no extract system anywhere in the house at the mo. Current thinking is a small in line fan. How it's triggered, via bathroom lighting, manual switch, occupancy sensor etc is tba.

You don't have sitting water on your DPM. Totally different scenario. It's to stop damp coming up not water getting down through it. If having the membrane under concrete was a good idea they would do it on commercial roofs and I've never seen it done in 36 years.

I've also gone down the route of modifying a Geberit wall mount cistern to incorporate pan extract: Solvent weld boss: Drilled a hole and Sika Flex EBT'd: Solvent weld pipe taken up through the stud wall into the loft. Not connected to anything yet! All buried in foam:

I'll say out loud I think it insane to have an inaccessible waterproof membrane under concrete. Under removeable pavers fair enough.

Easy to tamp concrete to falls and have it stay there and not slip. See p15 of my mega thread.

Something I've often wondered as I make by bathroom evermore airtight is how MVHR handles "natural" smells. Sod's Law the wife will bring me a cuppa in just as "somebody's" let rip. There's just nowhere for it to go and it's very noticeable. Presumably MVHR shifts this sort of thing pretty sharpish?

So your architect is a dick on two fronts? Specifying a non repairable design and assuming waterproof concrete doesn't exist?

Ideally the whole roof should slope to the drainage channel. What you can end up with is an ostensibly flooded roof, aka standing water that taken as a whole (or just in isolated patches that can't drain) will exert considerable sideways pressure and ferret out any weak points. I recently saw an upside down roof with this problem. The insulation was sat atop the asphalt. Part of the solution was to cut a series of Vs in the underside of the insulation. A guy did it by hand. So neat it reminded me of acoustic tiles. How about making good then tanking the reinforced concrete area. Then laying this stuff: http://www.abg-geosynthetics.com/products/deckdrain.html With the paving on top. Still not 100% on the roof make up? Mass concrete roof EDPM Reinforced concrete Paving ?

Couldn't resist:

Surely there is an industrial strength liquid tanking membrane out there that can be applied to make good the existing substrate?

I've never seen a roof done like this. Traditionally it was concrete, asphalt on top. Then chippings. Sometimes 2 layers of building paper and pebbles or slabs. I've seen hollow pot, straw insulation, lightagg etc. The "upside down" roof came next as I remember. Concrete, asphalt, insulation, pebbles/slabs. Fairly easy to rip up should the waterproof layer fail. Then came the exotics like Sarnafil.

Sika Sarnafil?

A car port over the top would sort this... A big worry also has to be any long, lapped joints in the edpm covering the main sections of the roof. Almost screams "hot tar job" to me. That being said there are different grades of asphalt according to use; roof, loading bay subject to vehicular traffic, car parks obviously.

Look out for the bait trail!

Sod's Law that on the left, the wall fixings for the rad come dead on a grout line as does the pipe coming out of the wall. It has nothing to do with poor planning! Still, should help hide the dodgy tiling between mosaics and plain!

Bought these and a couple of Pegler 15mm compression elbows: https://www.screwfix.com/p/drayton-trv4-white-chrome-straight-trv-lockshield-15mm-x/34063 Should let me put the valves up by the rad rather than down by the floor. @Nickfromwales, how many turns of ptfe tape in these fittings where it screws into the rad? Cheers

Ta. Tbh I only started thinking about it on the back of the Sunamp thread.

He. Thinking this assembly might be better? https://www.screwfix.com/p/drayton-trv4-white-chrome-straight-trv-lockshield-15mm-x/34063

Could you multipanel over a strong carcass and maybe use chrome quadrant edging?

Yep. Try it and see what you think. Whatever you do is a compromise when you go off piste!

Just take your time. See my sketch, you could drop the trim down a tad slightly below the tile so the corner of the tile sits in where the uncut leg and nib meet. Would mean a shallower angle to fill.

The towel radiator... It's going to have to sit a lot higher than I'd envisaged to look right. Currently balanced carefully on a Geberit box: So presumably I need to drop the valves lower onto the chrome 15mm stubs coming out of the wall? Then have chrome verticals coming up to the rad? Going to look strange having that trv on its own low down by the stub pipe. Thinking if I move the rad up a bit I can lose that line of rips at the cill? With hindsight maybe I'd have brought the stubs out of the wall higher up. Or should I just have the rad low? It's been a helluva long time since I've fitted a radiator and never a fancy one. Any glaring mistakes, tips etc? Cheers

Cast concrete? YouTube "concrete vanity top"

Can't believe you don't!