Mike Barnes wrote:

Hello Mike

MB| Bathroom reorganisation.

Commiserations. I've got to do mine this winter too.

OTOH, I've just discovered that the walled-in section I want to put
the shower is EXACTLY 1200mm across, which is EXACTLY the width of a
standard double tray so I don't need bespoke or homebuilt trays. Not
often that something like that happens! Not like it was intentional,
either. It's also 900mm deep, another standard size. Worrying.

MB| a new corner shower unit. I want the shower tray sitting
MB| directly on the floor so there's no appreciable height
MB| difference when stepping in or out of the shower.

Ah, that buggers up the normal method of boxing it up 2-3" and running
everything through the boxing. Sure you don't want to do this?

MB| * stud the wall behind the shower out a couple of inches
MB| and run the
MB| pipe though the gap

Possible, and probably the least hassle. You don't mention the shower
feeds, but you may be able to use this for them too, making a neater
finish.

MB| * cut a channel in the wall, which is single-leaf brick

Absolutely not.

MB| * cut a channel though the shower base, which is acrylic

Absolutely not, for it'll weaken it dramatically, make it bendy and
it'll split shortly after.

MB| * notch the joists and strengthen them as necessary - I
MB| will be putting
MB| thick plywood and a limestone floor on top of them

Unless they're particularly thick joists, I'd not do this as the
limestone will be adding a lot of weight and you don't want to be
weakening them unduly.

MB| Comments?

The first seems the best, and worthwhile adding some kind of
inspection/access panel if you possibly can (and not doing any tiling,
flooring until you're 100% sure it's working properly) I'd use
solvent weld for the waste as it doesn't tend to leak like compression
sometimes can.

--
Simon Avery, Dartmoor, UK
uk.d-i-y FAQ: http://www.diyfaq.org.uk/