Hello, after overlaying floorboards with ply is it necessary to leave for any amount of time before tiling, in case the ply will shrink slightly?

Heather - It is always advisable to bring the plywood into the room to be boarded at least 24hours before using so it can acclimatize to the room temperature.
Yes the plywood will shrink and the 'slightly' will depend on its thickness/type/storage etc.
Tile backer boards are the answer to this but if you've already fixed the ply down its now your choice!

A few more details will get a few more replies.

John.

Hi heather...ply will shrink and expand depending on moisture and thermal levels in the room and as john say's it is best to climatise the ply before fixing...

I tend to use cement backer boards now and this eliminates these issues.

Originally Posted by timeless john

Heather - It is always advisable to bring the plywood into the room to be boarded at least 24hours before using so it can acclimatize to the room temperature.
Yes the plywood will shrink and the 'slightly' will depend on its thickness/type/storage etc.
Tile backer boards are the answer to this but if you've already fixed the ply down its now your choice!
A few more details will get a few more replies.
John.

Hi John, Thanks for that it is good to know, I Haven't fixed the ply, it was just something I was wondering about for future reference. I'm not familiar with tile backer boards, how do they work?

Heather - Glad you haven't fixed the ply!
Dave's got all the links for tile backer boards etc. If you keep thanking him he'll come up with your info.

John.

Hi again heather.

John's lazy.. here's the pdf for the installation of the hardi-backer 250(6mm), this is the board that i use..

Also make sure the floor boards are well fixed first before installing the hardi..

Hardibacker board 250 pdf

Lazy - me! Don't tell the wife as she thinks I work 7 days a week!

I just knew you would pull the PDF for hardie backer boards out of your file!

And I can't compete with a PDF.

Thanks Dave

John.

Hi Dave and forum,

Thanks for the information. Is this ok to use Hardie-backer board with underfloor heating.

Thanks

Originally Posted by Dave

Hi again heather.

John's lazy.. here's the pdf for the installation of the hardi-backer 250(6mm), this is the board that i use..

Also make sure the floor boards are well fixed first before installing the hardi..

Hardibacker board 250 pdf

Helpdiy - Yes its ideal to use the Hardie backer board for UFH and don't you listen to Dave - I'am not lazy.

John.

John & all, thanks for your help. What else do I need before the underfloor heating can be put on. Am I understand correctly that first Hardiebacker board, second insulating board?, third UFH mat, fourth clue and last tile on? Help....we would like to get it right.

Originally Posted by timeless john

Helpdiy - Yes its ideal to use the Hardie backer board for UFH and don't you listen to Dave - I'am not lazy.

John.