On Wed, 18 Aug 2004 15:13:29 +0000 (UTC), "Charles Middleton"
wrote:


"Andy Hall" wrote in message
.. .
On Wed, 18 Aug 2004 13:29:22 +0000 (UTC), "Charles Middleton"
wrote:

This could be a bad idea. The waste plumbing for a shower tray is
either 32 or 40mm so I would check. Also you have to have a
reasonable slope for the water to run away. Drilling holes of this
size in a floor joist can be a bad idea because of the weakening
effect - I would seek professional advice on that.

Another badly planned project on my part then. I'm not sure what other
options I have and the shower & tray is arriving tomorrow. I thought that it
was safe to put holes in the joists providing that a) it was close to the
supporting wall and b) the hole went through the middle of the joist and c)
the diameter of the hole was no bigger than two thirds of the joist?

I am not sure on this. You could try pinging those in the know like
Tony Bryer.



Also, I was planning to put a slight incline on the run through the joists
to provide this.

Generally 18mm WBP ply (commonly available) is a good choice.

So board the floor with 18mm WBP and then mount tray on motor base on top of
that.

Yes.



You need a mortar base for the whole thing. This is to take out
unevennesses in the finish of the underside so that the load is spread
evenly. The manufacturer's instructions will normally stipulate it
and void the warranty if you don't.

So the mortar really provides a base between the ply and the bottom of the
tray which I presume doesn't touch the floor. Its likely in this case then
that the mortar will be contained inside and underneath the tray - no
problem.

Exactly. It needs to be under the central area and around the rim.
The manufacturer's instructions should give details, but normally
about 10mm or so is used.

Also you need to do some dry runs to align the waste plumbing. There
are shower bottle traps with a mushroom lid where you can remove the
strainer from the top. These have a rubber washer.

What I did was to do the alignment using wooden spacers to get the
height right and then adjust the plumbing. When fitting, I used a
smear of silicone under and above the washer and put it on the trap,
then positioned the tray, applied more silicone to the top part of the
fitting where it screws into the base and finally tightened it all.





CM.


..andy

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