How to make a 'bulkhead' behind bathroom basin?

Beenie

Currently we have a Roper Rhodes floor based cupboard unit with a built in basin. Water has damaged the bottom of the unit and looks untidy.

We want to change this to a wall-mounted unit with sit-on basin. We want to have a 'bulkhead' behind this unit to hide waste and water pipes which will now be on show at floor level.

If the bulkhead is (say) 3" deep and we extend it further up the wall, it will also make a nice shelf for soap dish and toothpaste etc.

The question is what material is best to make this bulkhead? MDF then tiled to match the rest of the bathroom tiles? Bushboard? Marine plywood that can be spray painted? How do you treat the join where the upright meets the shelf bit? Any ideas?

thearchitect

Well, the two key requirements are strength/rigidity and moisture resistance.

When we are doing them in the office (and assuming it's not a bespoke ISP system) we use marine grade veneer ply with pinned and glued timber trims/foredges.   One of my colleagues, however, is currently trying out wetwall on a project (although I think the trims don't look good on it).

Beenie

We wondered about the material used for wet rooms but couldn't see how you could join  90 degree angle neatly i.e the shelf join.

What do you do with your marine ply? I think paint would look cheap, but tiles might be difficult to fit on marine ply (you can tell I have no idea about waterproof materials). Is there an industry recommended solution or is it customer personal choice?

grumbler

I don't quite understand what exactly you want to make, but if it's just boxing for pipes, IMO the best materials are plastic soffit and fascia/capping boards:

Beenie

This is this isn't an ideal photo but if you look you'll see that the basin is wall-mounted but not on the actual wall - I've called it a bulkhead. Maybe that's the wrong word. However you'll see that not only does it hides all the nasty plumbing, it allows you to create a small shelf for bottles and other bathroom detritus. All  we want to know is the best material to construct such a bit of bathroom furniture. Looks like marine ply and tiles is the way to go.

grumbler

You can use (fibre-)cement backer board instead of plywood.

FreeBear

grumbler said:

You can use (fibre-)cement backer board instead of plywood.

Or Marmox type boards - You can also get right angle sections for corners & boxing in of pipes as well as niches (with or without adjustable shelves).

Make a frame out of treated timber, clad with boards, then render/plaster/tile over the top. Just remember to include access panels if you have any pipe joints, tap isolators, or traps hidden that might need servicing.

Gavin83

I think you need to work backwards for this. Work out the kind of look you want for the finished design, what materials you need to achieve that and then what base/framing you require. You can certainly build it out of wood, the rear of the toilet (hidden cistern) in our en-suite is entirely wood and that works well. Probably easier to go down the tile route though.

If you are tiling don't use plywood, use a backer board instead. I'd recommend something like Wedi as it's completely waterproof so you only need to seal the joints, although in reality given the area it's in a cement board would work too. Just build a frame, attach the board to it and tile over the top.

As for the shelf join again it depends on what kind of look you're going for. You could tile both the sides and the top and consider something like a mitre for the join. Alternatively you could tile the side and use wood on the top which is what we've done in our bathroom. We actually use walnut kitchen worktops but no reason you couldn't opt for something else. You'll need to give it a level of waterproofing though so either a suitable paint or oil depending what look you want.

In our en-suite where it's all wood we also applied several coats of polyurethane varnish to give it an extra level of waterproofness. The water just rolls off of it so that definitely works.