Newbie - Need to build a platform for a bathtub

[superkershaw]

Hello,
Long story short, I need to put a bathtub on a raised platform so that the water can drain into an outlet pipe that is about 40cm from the ground.

The shape of the room and the objects within it require the platform to be about 120cm tall.

I've made an extremely basic plan in sketchup and I don't know anything about construction nor do I really have the tools to do any complicated joinery so I am hoping to do it all with simple butt joints and metal braces.

Can anyone advise me if this plan is at all reasonable and if it will be okay to build this way?

I was thinking of using 78x98mm beams for the construction.

The overall dimensions are essentially (l x w x h) - 2000mm x 1050mm x 1200mm

The tub is a rather light clawfoot and I am a pretty light person as well. I don't plan on filling it with a ton of water for baths but rather more just for showers so it won't be heavy and full of water (although the option would be nice).

Endless thanks in advance as I am at a bit of a loss and need some wisdom and advice!

http://dl.dropbox.com/u/396112/_IMG/_misc/platform-tub.png

[Master Splinter]

Most house construction is simple butt joins and nail guns, so there's nothing tricky there.

Over here (Australia) the solution would be standard 90x35mm pine wall framing with studs at 450mm centres, top and bottom plates, and some braceboard to eliminate the chance of diagonal movement.

That frame would be supporting whatever bearers and joists are required by your local building code for domestic flooring loads. Doesn't matter that you are never going to fill the tub with water, it's still a floor and has to be built to the applicable standards for trafficable flooring.

Depending on the span, you may be able to do away with the need for bearers, or add a third stud wall in the middle to reduce the span to acceptable limits for whatever size joists you use. That'll depend on which way the underfloor support runs, though.

Your local building code may also require that you have a direct load path from the studs to the joists - ie the bottom plate of each stud wall should be directly above and parallel to the joists so that there is maximum load transfer rather than point loads over the middle of an unsupported floor section. This'll require checking to see what exactly you can get away with (here they have to be no more than 1.5 times the joist depth away to be considered as suitably supported).

Your local codes may also stipulate that since it is over one meter from floor level, it requires a compliant handrail, compliant stairs with non-slip covering as it is in a wet area, waterproofing membranes to all surfaces and so on......

Are you sure you can't just dig a deeper hole and recess the pipe a bit more?????