I am currently embarking on (amongst other things), refitting my bathroom.

My master plan requires the bath to be removed from its current location against a window and across floor joists, and it's replacement to be located against the adjacent wall, away from the window (so i can shower properly), but consequently in line (parallel) with the supporting floor joists.

On new build housing, it is always required that joists are doubled up when running parallel with bathtubs, for loading purposes.

However, retrofitting additional floor joists would be a nightmare. I would much rather layer (say) 18mm chipboard or marine ply across the floor, after removing the old floor boards (which have been hacked about during CH retrofit), so I can lay a laminate floor on top. This should then give a continuous deck below the bath and (hopefully) spread the load across the floor.

Does anyone have any comments/suggestions on this approach. I'm sure plenty of people move their baths around with no consequences.

ALL comments appreciated.

In article , Kevin Brady wrote:
On new build housing, it is always required that joists are
doubled up when running parallel with bathtubs, for loading
purposes.

That's a new one on me too. Domestic floors are designed for an
imposed loading of 1.5kN/m2 - 30lb/ft2. A standard bath is 5'6'x2'4",
say 13ft x 30 = 390lbs. The bit of floor next to the bath is probably
taking next to no load while you're in the bath but is designed to
take another 390lbs. So you've got loads of strength there. In
addition it's usual to use the same size floor joists across the whole
first floor whose size is dictated by the longest span, and those
under the bathroom floor probably have a shorter span so loads more
capacity than the above.

What would be prudent would be to put a solid timber spreader under
the bath feet if they would otherwise just be bearing on chipboard,
perhaps midway between joists.

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"Kevin Brady" wrote in message
...

I am currently embarking on (amongst other things), refitting my
bathroom.

My master plan requires the bath to be removed from its current
location against a window and across floor joists, and it's replacement
to be located against the adjacent wall, away from the window (so i can
shower properly), but consequently in line (parallel) with the
supporting floor joists.

On new build housing, it is always required that joists are doubled up
when running parallel with bathtubs, for loading purposes.

However, retrofitting additional floor joists would be a nightmare. I
would much rather layer (say) 18mm chipboard or marine ply across the
floor, after removing the old floor boards (which have been hacked
about during CH retrofit), so I can lay a laminate floor on top. This
should then give a continuous deck below the bath and (hopefully)
spread the load across the floor.

Does anyone have any comments/suggestions on this approach. I'm sure
plenty of people move their baths around with no consequences.

ALL comments appreciated.

Kevin Brady


I don't think I'd be to concerned about the joists, but rather about the
flooring grade chipboard that makes the final surface. Most building have
joists that will take quite a bit of loading, but the floor boards and other
final layers are less robust. So make sure you spread the loading of the bath
across a double layer of boards, at the least, so you know the thing isn't going
to push its feet through the floorboards.