Mapei Technical re floor

[DavieA]

Hi All, I know the backerboard/ply disscusion has been had to death but after chatting to mapei has got me thinking:yikes:.

So some mapei products such as keraquick with or without latex are used to bed down backerboards to a ply or chipboard sub along with mechanical fixings, so it obviously bonds to these materials. Also Keraquick or keraflex maxi is suitable to bond a decoupler to a ply or cementboard sub.

I know alot of pros try to avoid tiling onto ply because of expandsion issues due to moisture and prefer to overboard with a cement product for stability but if your faced with a floor that needs strenghtened it must be ply'd. However if using a decoupler on the installation im thinking that it could be applied using keraquick with or without latex onto the ply sub providing its correct thickness ie 15mm wbp, 2mm expansion gap between sheets, fixed at 150-300 centers and as been primed back and sides as the decoupled will act as a waterproofing to the sub ensuring the ply never become effected by moisture.

any thoughts or anyone agree?

http://www.youtube.com/watch?v=mDqiAEB4Ads&feature=related

 

[The D]

sounds spot on to me

 

[The D]

i do have some issues with that video. at the start you see a tile that is fixed but the adhesive is about 20mm from the edge of the tile you see it again about half way in to the clip. also IMHO the adhesive is a bit stiff and so is the grout.* * *

*

 

[Time's Ran Out]

You lost me!
Not sure if there is a question here or are you asking which would be preferred - plywood with cement board or plywood with decoupling membrane, and is the plywood fixed to the floorboards/weyroc or direct to the joists.

 

[DavieA]

Haha sorry John, I was basically asking if anyone would agree with me that in a situation where a floor had to be strenghtened therefore ply'd wheither there was a need to overboard with a cement product if a decoupler was being used?

Floor setup is 22mm chipboard screwd to joists, 15mm wbp ply screwed at 150 centers then decoupler and tile using keraquick which is suitable for use on timber floors

 

[Time's Ran Out]

I'am back!
I use a fast set flexible adhesive by another manufacturer so the adhesive is your choice.
In the present days of technical development (ie since building paper/chicken wire/sand & cement) and the floor being deflection free, the cheaper option seems to be with some decoupling membranes which have as you say the waterproofing added factor.

 

[DavieA]

So John from that can I take it you also agree?

"If decoupler is to be used in an istallation theres no need for a cement board "