Best method to fix toilet pan to LVT floor over two layers of 18mm hardboard

[dragonfly101]

I have a carpenter replacing my knackered upstairs bathroom floorboards with 18mm hardwood ply. He's kindly screwed an extra layer of ply underneath the area where toilet pan fixing screws will go, so that they have 36mm of wood to be secured in (plus the 4mm of LVT on top).

I've just been reading conflicting opinions though on whether toilet pans should be screwed to the floor at all though. My existing pan has screw holes each side which were being used before. I've seen some people saying the pan should be fixed down on the floor with mastic only, and the screw holes in the pan should be filled with silicon to prevent spills running through them and getting under the pan where they've nowhere to go. Also, if the screws were done tight enough to actually hold the toilet down absolutely rigidly with zero play at all, you would probably break the ceramic pan as you screwed them down that tight.

Conversely, I see others insisting you mustn't put any mastic or sealant around the toilet pan, and it should be secured with screws only.

 

[footprints]

Screws for me unless the pan/floor are very uneven them a bed of mastic helps. I always run a thin bead of silicone around the pan and the finished floor anyway. Do invest in some brass or stainless screws it can save a lot of trouble later.

 

[blup]

Stick it down with sealant, cut the head off the screws and mastic them into the holes for appearance sake

Blup

 

[RandomGrinch]

I've used stainless steel coach screws and washers - I'm happy that it's absolutely rigid, although I put an extra noggin in the floor to screw into, just to make sure!

 

[Madrab]

Always screw the toilet down using brass screws or fitting kit, people tend to dance around when they're on the toilet and I've lost count how many toilets I've had to re-fit because someone just used silicone and it's eventually partied company with the floor. The screw holes are there for a reason IMO

 

[blup]

So that's what Scots mean when they say they love a wee dance.

Blup

 

[oldbutnotdead]

If you're lucky the loo will have some plastic cup washers with it (to spread the pressure from the screws around the hole). If not then 1/2" tap washers are an ok substitute- with brass or stainless screws- you get a solid fix with enough give to cope with timber floor movement

 

[Madrab]

Brass is the traditional fixings for ceramics, they are non ferrous so don't rust and as they are soft they tend not to damage the ceramic. S/S screws really need to have a plastic sleeve as they have the potential of damaging the ceramic, as S/S is much harder.