On Sat, 6 Jan 2007 02:16:39 +0800 Lisa Bates wrote :
If we raised the floor by 20cms this would hide all pipes.
(The existing floor is joists and floorboards. The old bath
suite had a cast iron bath, so can take weight.)

How do we do this?

The easiest way will be to fix some bearers, say 50x75, across the
existing joists (i.e following the line of the floorboards) at
900-1200c/s and then 50x100 joists above them at right angles. You
can then run pipes under the floor in either direction without
notching. Finish with moisture resisting chipboard or ply.

If you need to lose a WC branch within the floor adjust the sizes
accordingly.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk