Sealing chipboard, yes or no?

[RichD1]

I'm laying a new floor in my utility including new floor joists. The intention is to put tile backers on the chipboard before laying ceramic tiles.

Sound I seal the new chipboard with a water resistant finish like water seal or varnish or will the adhesive used to lay the backers on be sufficient? BTW, the floor has been insulated with 100mm celotex and all joins and joists covered in aluminium foil tape.

 

[opps]

The following might be useful.

No More Ply Fixing Guide.pdf

drive.google.com

 

[RichD1]

So I assume the answer to my question is no. Sealing properly around the backer boards will do the job. Or should I put some SBR down first?

 

[opps]

I don't see any harm in using SBR first. It is a very cheap product but if you use the polyurethane glue, and use it properly, it should not be required.

PU glue expands (a bit like expanding foam) and creates a water resistant seal.

 

[RichD1]

We’ve changed our minds, going to fit vinyl click flooring instead. It says it is 100% waterproof but I’d still like to seal the chipboard first. Is SBR the best product for this or should I look at a solvent based solution?

 

[opps]

We’ve changed our minds, going to fit vinyl click flooring instead. It says it is 100% waterproof but I’d still like to seal the chipboard first. Is SBR the best product for this or should I look at a solvent based solution?

Belt and braces- tank it.

I will defer to others to recommend a tanking solution