Gap between wall and wall hung toilet

[Robin123]

Hi,
My builder fitted a wall hung toilet with a soundproof foam mat and I can see a3 mm gap between the end of the toilet seat and the wall tiles when I sit on it. The sealant is not on yet as the builder will put it on later once the bathroom is comlete. The wooden structure behind the tile backer board is solid, wall and tiles flush and there is no movement on or behind the wall.the foam is compact at the bottom of the toilet and compresses more when load is applied. is a little movement creating a gap expected for wall mounted toilets when you sit on it?or does something need to be adjusted? Thanks for any advice.

 

[Alec_t]

The gap looks wider at the top than the base, so it seems the floor is flexing locally.

 

[Robin123]

Hi Alec. The foam that is behind the toilet gets compressed at the bottom so I think that's why the gap is narrow there and not at the top..the foam at the top isn't compressed when someone is sat on it... so now it permanently looks narrow at the bottom as the foam is so compact. Is it generally recommended to use the foam? When you say that the floor could be flexing..what do you mean? And do you know how I could check/prevent this? Thank you

 

[Alec_t]

Is it generally recommended to use the foam?

If it wasn't recommended then the toilet manufacturer/installer wouldn't have provided/used it .

When you say that the floor could be flexing..what do you mean? And do you know how I could check/prevent this?

The floor at some distance from the foam line is moving downwards when there's weight on the toilet. Reinforce the floor supports if practical and you're really concerned about the movement.

 

[Tdw1982]

Surely with a wall hung toilet, it is more likely the panel holding the toilet, or the fixings are loose.
Seems extreme that a toilet that isn’t touching the floor is flexing because the floor is moving.