Expansion gaps in ply?

[2020Tiling]

Hi, I have just had to sort a job out I done 12 months ago due to stress fractures , all cracks where between the expansion gap between the sheets of ply running in a line. I have lifted 15 tiles and would like to know what I did wrong in the first place ( apart from using ply) substrate was chip board with no bounce so I over boarded with 18mm Marine ply as I had a lot of height to play with, I staggered the boards & left a 3-4mm gap between boards and screwed each board every 150mm. I filled the gaps with SPF while tiling the floor. Any ideas what I did wrong and how to correct it after I have lifted the tiles? Cheers. Tiles are all Ceramic.

 

[White Room]

What room was it you tiled....

 

[2020Tiling]

Kitchen mate! It's been a nightmare..

 

[Protilers]

hello 2020,

did you "cross" the joins of the chipboard?..........
IMO you should have filled the gaps with silicone and not spf.......the spf made it "really" rigid......silicone would have allowed some give!

check this out:

[video=youtube_share;gJo-DcwZKbw]http://youtu.be/gJo-DcwZKbw[/video]

hope it helps

Lee

 

[2020Tiling]

Great clip mate Cheers! That explains a lot. I have been stopping the ply from expanding due to filling the gaps with SPF instead of silicone

 

[2020Tiling]

So I should be ok if I get rid of the SPF in the joints , then fill them with silicone and maybe scrim tape ?

 

[Protilers]

Great clip mate Cheers! That explains a lot. I have been stopping the ply from expanding due to filling the gaps with SPF instead of silicone

exactly........expansions are always filled with either silicone or a dedicated expansion joint!.......

best of luck in the future!

Lee

 

[DHTiling]

Kitchen floor.. ? .. Is it a floating floor ?

 

[Time's Ran Out]

It's time to re write the instruction manual on floor preparation now IMHO .All wood will 'breathe' so it needs to be covered before the introduction of a moisture layer of adhesive so either a uncoupling membrane or cement boards should be used.

 

[2020Tiling]

Not a floater mate.

 

[2020Tiling]

So why do they recommend using SPF to fill the gaps in Cement Board? surely it would be a safer option to use silicone even though it should be rigid.

 

[2020Tiling]

Will Ditra or similar stop stress fractures?

 

[On one]

It's time to re write the instruction manual on floor preparation now IMHO .All wood will 'breathe' so it needs to be covered before the introduction of a moisture layer of adhesive so either a uncoupling membrane or cement boards should be used.

On a similar note....I can recollect from memory(a few years ago now) that 1 adhesive manufacturer required that overboarded wooden floors had to be ventilated.....so theoretically every 400mm(joist spacing) you would have to have have a vent hole........practically unlikely......but a get out clause for any failures.

 

[On one]

Will Ditra or similar stop stress fractures?

Not if you have any vertical movement in the floor joists