re-inforcing a wooden floor

[clueless111]

We are replacing our bath with a double bath which holds 250 litres so by the time 2 people are in it will be very heavy so I would like to re-inforce the floor.
There are floorboards down and the bathroom is upstairs above the kitchen which I don't want to end up in
What is the best way to do this?

 

[JohnD]

Look to see which way the joists run - from end to end of the bath or from side to side?

What you want to do is to spread the load from the four small feet of the bath across several joists. You can do this by putting a substantial piece of wood under the feet so it spans several joists.

Joists are typically at 16" centres. If you have no other way of telling, look for the rows of nails through the floorboards.

Something like a piece of 2"x4" on its side. it will only raise the bath by a couple of inches, and the feet are usually adjustable for height anyway.

When you do this it is not relying on the strength of the floorboards.

If you want to tell us what the floor is made of, and how thick, and how big the joists are, and which way they run, this will be helpful. Also, how close is the bath to a structural wall, and is it end-on or side-on; and which way the joists run.

 

[Jasonb]

And while you have the floor up I would suggest replacing the T&G or Chipboard with 22-25mm WBP ply if you intend to tile the floor. This will not only help spread the load but reduce the height build-up when tiling.

Jason

 

[clueless111]

Thanks, I did ask someone who likes to hand out diy advice and they said I would have to re-inforce the joists, e.g. put wood either side of the joists.
So as long as there is a good size sheet of wood under the bath this would be sufficient.
The floor is to be tiled eventually, would a piece of wood covering the whole of the floor be ok? Or is that not needed atall?

 

[JohnD]

Look to see which way the joists run - from end to end of the bath or from side to side?

If you want to tell us what the floor is made of, and how thick, and how big the joists are, and which way they run, this will be helpful. Also, how close is the bath to a structural wall, and is it end-on or side-on; and which way the joists run.

any answers?

 

[clueless111]

sorry, they are running the same way as the bath is going.

 

[JohnD]

and?

 

[clueless111]

OOOps, the bath fits in wall to wall ending on a structural wall (tap end) and its full length is against a party wall.

The width of the joists are 2" and depth 5", and are 18" apart. The floor is floorboards which are approx 1" thick

 

[JohnD]

OK

Because it is so close to a wall the joists will be strong and not deflect much (it would be worse if the bath was in the centre of a large room)

Just put a piece of 2"x4" on its side as a bearer under each pair of feet, spanning crosswise over as many joists as you can manage while still being concealed by the panelling.

If you need to put down any new flooring, use 25mm WBP ply.

Chipboard is very weak, and falls apart if damp.

 

[JohnArnoldBrown]

I wouldn't worry too much about the extra weight of the two people, though.
See Archimedes.

 

[Symptoms]

Well, up to a point ... the principle that the weight of the liquid displaced by a floating body is equal to the weight of the body. Prof Speak: ‘an object totally or partially submerged in a fluid displaces a volume of fluid that weighs the same as the apparent loss in weight of the object (which, in turn, equals the upwards force, or upthrust, experienced by that object).’ For clueless's situation it's only relevent if the bath is full to the brim, then he/she & partner get in slopping the displaced water all over the floor (thank goodness it's not chipboard!)

Like JAB I wouldn't worry too much either unless the double bath is a MONSTER. Spread the weight.