Floor tiling - floor reinforcement

[MartynG]

I am planning to tile our bathroom floor. I am aware that I will have to reinforce the floor but do not want a step into the room.

I am considering lifting the floorboards and putting down two layers of 12mm ply (not overlapping) but I am still unsure whether this would be sufficient.

My joists are 14" apart and approx 3m long. I was wondering whether bolting a steel plate to a side of some or all of them would work or even sandwiching the steel to make up a flitch plate. Is this ever done or are there better ways.

 

[Symptoms]

Martyn - once the old floorboards are up sheet with 25mm exterior grade plywood (WBP) as this will firm-up the floor below the tiles, screw this ply to the joists. If you have to introduce any joins in the ply ensure these are directly above joists or introduce noggins for support.

 

[MartynG]

Martyn - once the old floorboards are up sheet with 25mm exterior grade plywood (WBP) as this will firm-up the floor below the tiles, screw this ply to the joists. If you have to introduce any joins in the ply ensure these are directly above joists or introduce noggins for support.

Thanks for your help Symptoms, 25mm it is.

 

[curium]

I had a similar conundrum but one good thing about my new build is that once I'd lifted the carpet I found 25mm ply already in place (I measured the thickness through the hole where the pipes come through) so I plan to tile straight on top.