Floor deflection videos...

[zzr-matt]

My bathroom floor is 12" x 2" joists on 400mm centres covering a 3.0m span. This is overlayed with 18mm chipboard screwed to the joists overlayed with 12mm ply screwed on a 5" grid. The ply had its edges and back face coated in SBR.

The tiles are 600 x 300 porcelain laid on a single part Granfix S2 rapid adhesive on a full bed and has been grouted with mapei ultracolor plus white grout about 2 days after the tiles were laid.

There are some small cracks appearing in the grout after a couple of weeks as can be seen in the photo below.

I have places a glass of water on this tile and jumped around the glass whilst taking a video of it, these are shown below.

Does this look like a subfloor deflection issue or is something else amiss?



[video=youtube_share;9p5ealPD2ug]http://youtu.be/9p5ealPD2ug[/video]

[video=youtube_share;Kadn3XuBB58]http://youtu.be/Kadn3XuBB58[/video]

 

[DHTiling]

Nice bunny hops :lol:

How soon after tiling was the floor walked on..? and it does look rather shallow in the joints..

The deflection seems to be ok..

 

[zzr-matt]

Cheers! I was going for ultimate floor failure with the bunny hops!

It was at least 18hrs between laying and walking on, no rockers or hollow sounding tiles.

The ply was down for a number of months, i wonder if its moisture content is settling to a new level and its shrinking slightly.

Reckon its best to leave it for a couple of weeks and see if it gets worse? Or is it demolition sunday tomorrow?

 

[DHTiling]

No no no not yet... how wet did you mix the grout..?

 

[zzr-matt]

Mixed so that it would hold a peak in the bucket. I may have been a bit quick to start sponging down hence the joints not looking that full.

Whats the correct proceedure for grouting?

 

[Sean SML Tiling]

Aint the ultraplus normal adhesive not flexible?

 

[DHTiling]

Aint the ultraplus normal adhesive not flexible?

ultra colour plus is flexible grout..

 

[Sean SML Tiling]

My mistake, Must be getting them mixed up. The joints do look pretty empty unless its lippage.

 

[zzr-matt]

No lippage i razor bladed each joint for an anti lipped finish. Unfortunately my grouting skills werent quite as good.

 

[DHTiling]

No lippage i razor bladed each joint for an anti lipped finish. Unfortunately my grouting skills werent quite as good.

rake out the grout... mix stiffer and leave to set longer before washing off...


if it cracks again , then you have a deflection issues at said point.

 

[zzr-matt]

Cheers Dave. How thick should it be mixed and how long would you leave it before cleaning down?

 

[DHTiling]

Normally that grout is 1.1 to 1.3 ltrs of water per 5kg bag.. but i mix it thicker as as the polymers soften whilst leaving to slake it can go wetter... so stiffer than normal i say but wet enough to bond.

 

[Ian]

Is there definitely no join in the ply under that grout line?

 

[zzr-matt]

Defintely no join. Its about 500 mm to the nearest join one way and 700 the other.

 

[Mr T]

loved that vid lol... mate it doesnt matter how long after grouting you sponge off.. Just dont put any pressure on the sponge at all when your doing it and you wont dig into the grout joint... But you do have to wait for the grout to start setting before you buff.

 

[DHTiling]

loved that vid lol... mate it doesnt matter how long after grouting you sponge off.. Just dont put any pressure on the sponge at all when your doing it and you wont dig into the grout joint... But you do have to wait for the grout to start setting before you buff.

Sorry but that is so wrong advice.... Ultra colour is a fast setting grout , leave it too long and it cannot be tooled..

 

[Mr T]

Sorry if its bad advice I thought you have to wait for grout to start setting before you buff off mate

 

[Rizzle from the Portizzle]

looks like the grout joint is to wide to hold the thin grout bed you washed it down to thin leaving the tile edges prone to damage and probaly mixed the grout to dry need to rake out do again what sponge did you wash it off with a cheap sponge will pull out the grout .try washing off with an ardex sponge not wet just damp and do one sweep at a time cleaning spong after each sweep

 

[SJPurdy]

What type of ply was used?

 

[Sean SML Tiling]

Whats the ardex sponges like and how much? I use the nicobond sponge which is 4 quid each a little steep for a sponge but very good.

 

[zzr-matt]

What type of ply was used?

12mm WBP

 

[zzr-matt]

looks like the grout joint is to wide to hold the thin grout bed you washed it down to thin leaving the tile edges prone to damage and probaly mixed the grout to dry need to rake out do again what sponge did you wash it off with a cheap sponge will pull out the grout .try washing off with an ardex sponge not wet just damp and do one sweep at a time cleaning spong after each sweep

It wasnt an expensive sponge. What should the ideal ideal grout line look like? Should it just be flat with the tiles or marginly concave but lapping up to the face of the tiles? Any close up example pics would be cool.

 

[DHTiling]

Sorry if its bad advice I thought you have to wait for grout to start setting before you buff off mate

It was this >>>>

doesnt matter how long after grouting you sponge off.

bit i was on about ... it does matter how long you wait

 

[Mr T]

oh no I meant he can do. It straight away as in a prev post he mentioned sponging off too quickly which is wrong.

 

[Houston]

me personally, I dont think its deflection, i would use bal gt1 admix with a bal grout and this will enhance the flexibility more than your pre bagged bal flexible grouts

 

[Stef]

me personally, I dont think its deflection, i would use bal gt1 admix with a bal grout and this will enhance the flexibility more than your pre bagged bal flexible grouts

If its not a deflection issue why would he have to use a flexible additive?

It could be a number of things as already stated...

 

[Houston]

If its not a deflection issue why would he have to use a flexible additive?

It could be a number of things as already stated...

the floor is not bouncing,are the tiles loose? i dont think they are. If there's been a failure with the grout onto the wooden substrates, the gt1 admix will solve the problem.

 

[DHTiling]

@zzr-matt

Can you see any deflection at the point where the grout is cracked, say at the tile corners etc.... this could just be a bonding issues to the substrate..

 

[zzr-matt]

If i stand on tip toes on each end of the tile and try and rock the tile there is no movement!

 

[DHTiling]

I would just re-grout and see what happens from there...