18mm WBP ply prior to tiling

[chris_elevate]

I’ve bought 18mm WBP ply for the bathroom to fix directly to the joists and got noggins every 400mm.

Is this base ok to tile onto with flexible adhesive and grout? It’s having electric UFH too.

The reason I went for 18mm is because it’s 18mm floorboards running to it at the door threshold.

Thanks

 

[Andy Allen]

I would put some 6mm insulation boards down first..

 

[chris_elevate]

Warmup insulation boards like these you mean?
Warmup Insulating Board 6mm | Topps Tiles - https://www.toppstiles.co.uk/tprod4423/warmup-insulating-board-6mm.html

 

[Old Mod]

I would put some 6mm insulation boards down first..

On top of the ply tho Andy yeah?

 

[jobdone]

Insulation boards as above but there are more cost effective suppliers than topped. CTD keep Jacko board in stock.
Or try the forum sponsor U Heat

 

[chris_elevate]

So you don’t think it’s possible to put the UFH and tiles down onto the 18mm ply? You think it best to use 6mm backer boards prior to the job? Screws at 100mm centers too?

 

[Dumbo]

Ply is not what is was . Tiling will probably delaminate from background and you could get tanins coming through staing the grout

 

[chris_elevate]

So to be 100% spot on you guys suggest the following...

1. Lay the 18mm WBP ply down onto the joists and noggins at 400mm centres. Use something like gorilla glue (expanding glue) on top of the noggins/joists if considered necessary to stop any creaks etc but not essential.
2. Overboard it with sheets of 6mm tile backer board and screw through at 100mm centres.
3. The tiler can then go straight onto this with the UFH wire and tile on top.

Thanks again for the input.

 

[jobdone]

Insulation boards
Heating cable
SLC
Then tiles. Better heat distribution and far easier to lay the tiles on flat smooth surface. Less likely to damage the cable.

 

[Andy Allen]

On top of the ply tho Andy yeah?

Yes mate......ment before the ufh..

 

[chris_elevate]

I've just found this in the WarmUp manual....

"SUBFLOOR TYPES Timber Subfloor: Secure existing floorboards. Floor boards should then be over boarded with a Warmup insulation board (min 10mm) or WBP plywood (Min 18mm) screwed down at 200mm centres.

Fixing Ply directly to joists will not provide a stable floor finish to accept the tiles. Fixing 18mm tongue and groove then over boarding with WBP plywood or the Warmup Insulation board."

So they are saying I need 18mm followed by 10mm insulation board on top? Surely having 28mm plus adhesive and tiles will create a "step" from my landing carpeted floor into the bathroom at this rate? My landing floorboards are 18mm.

Thanks for your input on this.

 

[Flintstone]

18mm ply is structural, same as a floor board is. The 6mm insulation is to insulate, and also give you a better more suitable surface to tile on than ply wood.

 

[Dumbo]

As regards your step . Function over form not form over function. What mean is if it works you will get over the step . If you take form over function and it fails you wont get over that . Probably you have come up a flight of 8 inch stairs i sure yiu can manage a little step into your bathroom . Dont forget descent underlay and carpet probably 20mm .

 

[hmtiling]

I'd glue and screw the insulation to the ply using an s1 adhesive.

 

[chris_elevate]

So 4mm notched trowel onto the 18mm ply with the s1 adhesive, 6mm insulation boards onto that, screws every 200mm, glass fibre take along the joins and it’ll be ready you’d say?