Floor preparation advice

[jackthehat]

Quick hello to all who reads & responds to the post.

I'm after a bit of advice and guidance on a floor preparation prior to tiling.
Bathroom will consist of a wetroom with underfloor heating.

In order to keep the floor as low/original as possible I'm thinking of ripping up the old floorboards & fitting 18mm hardwood ply screwed down onto the joists & then placing 6mm insulated tile backing board over the ply.

I'm a lil unsure of how to prep the different layers-
Does this sound correct:

• 18mm hardwood ply on joists screwed down 250mm apart
• Bal single part flexible adhesive with notched trowel on top of the ply and then fix the insulated backer board to the ply with screws & fixing washers.
• Fit loose wire heating & fix tiles to the backer board with Bal flexible adhesive.

Upon tanking the wetroom- should I "overtank" the wetroom by 50mm or so or just the former tray and wetroom walls?

Regards
Jack

 

[Qwerty]

All good apart from once UFH down, I would SLC then tank the whole floor (not just wet area). You can tank just past the former, but I would go the whole hog personally.
What size is the floor? and what make of insulation boards?
You could utilise the insulation boards as the tanking depending on the make & method of fixing

 

[TJ Smiler]

Agree with PlanTec, If it was me i would go the whole hog and tank the lot and i always latex over my U/H Wires.

 

[jackthehat]

Thx for the replies

The floor is just shy of 6sq's (3 wetroom walls 8.1sq's) so I'll order another kit and tank the lot for peace of mind.

Insulation backer boards are Jackoboards- edges slightly damaged during shipment but nothing the waterproofing tape wont be able to seal.

So to recap-

Rip up floorboards
18mm hardwood ply screwed to joists
Flexible tile adhesive on top of the ply
6mm Insulated backer boards screwed on top of the ply & all joints sealed properly
Uhf goes down next
Latex Slc to just above the wires
Tank up the whole room & then start tiling.

Regards
J

 

[Qwerty]

Thx for the replies

The floor is just shy of 6sq's (3 wetroom walls 8.1sq's) so I'll order another kit and tank the lot for peace of mind.

Insulation backer boards are Jackoboards- edges slightly damaged during shipment but nothing the waterproofing tape wont be able to seal.

So to recap-

Rip up floorboards
18mm hardwood ply screwed to joists
Flexible tile adhesive on top of the ply
6mm Insulated backer boards screwed on top of the ply & all joints sealed properly
Uhf goes down next
Latex Slc to just above the wires
Tank up the whole room & then start tiling.

Regards
J

You got it!

 

[beanz]

You'll need to add plenty of noggins to get your 250mm centres.. It's no good just doing the 250mm down the existing joists. You may or may not, already realise this, but just in case.

 

[Tony Robins]

Sounds as though you've get everything covered.