Floor Adhesive Not Bonding To Floor

[kstandsteve]

I have just finished tiling my bathroom floor. I have used BAL Rapidset Flexible Adhesive onto a timber overboarded floor.

However I noticed one tile seem loose and when I tried lifting it it wasnt stuck down at all. It hadnt bonded to the timber.

Dreading the fact now I have to start all over again.

Should I have primed the floor with something first??

Steve

 

[Richard C]

I have just finished tiling my bathroom floor. I have used BAL Rapidset Flexible Adhesive onto a timber overboarded floor.

What did you overboard with? What is the original floor underneath? Is there any flex in the floor? Did you walk on it before the adhesive had fully set?

However I noticed one tile seem loose and when I tried lifting it it wasnt stuck down at all. It hadnt bonded to the timber.

What sort of tiles are they? Is it just the one tile or are there more the same? Has the adhesive stuck to the underside of the tile? Has the adhesive fully hardened or is it powdery? How wet did you mix the adhesive? How did you apply the adhesive?

Dreading the fact now I have to start all over again.

If it hasn’ bonded you have little choice but you need to establish what went wrong the first time; no point in making the same mistake twice.

Should I have primed the floor with something first??

Priming the tile surface is not normally necessary with WBP ply although BAL recommend sealing the back with SBR primer. Did you use Admix AD1 in the adhesive mix?

 

[kstandsteve]

Cheers for reply.

Its overboarded with normal 6mm ply over original t&g boards - there is no flex in the floor its really sturdy.

The tiles are common 450 x 300mm Ceramic floor tiles - all the same - edges are cut down to 3/4 tile as I have centred the pattern on the floor so no small tile pieces.

The adhesive has set well and is stuck to the back of tile - in fact I would say thats not going to come off! Which prob means I need new tiles now.

No didnt use any admixtures just 4:1 by weight - used scales and did this spot on. What is AD1? - Just looked it up it doesnt mention using it with Rapidset Flexible??

Edit - One thing I did do which may be a factor. I used the "half round" notched trowel not the castellated square type - anyway I applied the adhesive to the tiles rather than to the floor as I found this easier as the tiles were quite big.

 

[Richard C]

Its overboarded with normail 6mm ply over original t&g boards - there is no flex in the floor its really sturdy.

What type or ply did you use? Was it dust free & clean when you laid the tiles? Also, 6mm ply is nowhere near thick enough for over boarding; it takes very little flexing to cause failure in just a few months. British Standards & BAL recommend 15mm minimum but in most cases 12mm should be sufficient, it depends. If I over board I always fix through with screws into the joists not just into the top of the floorboards; locate any pipes/cables first.

It doesn’t sound as if this has caused your problem though.

The tiles are common 450 x 300mm Ceramic floor tiles - all the same - edges are cut down to 3/4 tile as I have centred the pattern on the floor so no small tile pieces.

Fairly large tiles, even more reason for using a thicker overboard.

The adhesive has set well and is stuck to the back of tile - in fact I would say thats not going to come off! Which prob means I need new tiles now.

Sounds as if the moisture has been sucked from the adhesive before it had a chance to bond; either it was too stiff/dry, spent too long in the pot (only mix enough for 35 mins), was of insufficient thickness &/or the tile sucked all the moisture out; what size notched trowel did you use?

No didnt use any admixtures just 4:1 by weight - used scales and did this spot on. What is AD1? - Just looked it up it doesnt mention using it with Rapidset Flexible?

See page 2;
http://194.223.92.131/pdf/Technical Data Sheets/B & C Technical Data Sheets/BAL_Rapidset_Flex.pdf

Edit - One thing I did do which may be a factor. I used the "half round" notched trowel not the castellated square type - anyway I applied the adhesive to the tiles rather than to the floor as I found this easier as the tiles were quite big.

As a general rule you should never apply the adhesive to the tiles, always to the floor/wall. The tile must be set onto a continuous bed of adhesive once it’s pressed into place, what size notched trowel did you use?

I’ve only used BAL products for many years & have never had a single problem or failure. They are one of the best (although expensive) on the market, providing you use the correct product for the application & follow the manufacturer’s instructions.

 

[kstandsteve]

Hmm sounds like the ply is a bit thin but as you say it sounds more a bonding problem. Poss the ply used not being ext grade. The trowel was a circular 10mm one.

No probs with mixing and using the adhesive I only nixed enough for 4 tiles at a time.

The pdf data sheet is very interesting as its different to what it says on the bag! It doesnt mention admixtures on the bag for timber floors. I have tried calling bal but they are shut till next week.

 

[Richard C]

Hmm sounds like the ply is a bit thin; Poss the ply used not being ext grade.

Definitely too thin & you should always use exterior grade WBP, ordinary ply will delaminate if it gets wet to any degree. You don’t need Marine ply though, its way OTT. Personally, I prefer to remove the old floor & start again using either 18 or 25mm WBP (depending on the floor construction) as this has a negligible effect on the threshold height. If you do have to start again, you should seriously consider replacing that 6mm ply with 12mm or overboading with a decent tile backer board is probably a better solution if not replacing the floor entirely.

it sounds more a bonding problem.

Unusual if the mix is right but I would say so. I just mix by eye, similar to the consistency of soft ice cream; I don’t know how this equates to the stated adhesive/water ratio. Always clean your tools & mixing bucket with clean water before starting a new mix or the residue will cause the new mix to go off quicker, mix at slow speed & if using an electric mixer & over mixing also causes aeration & the mix to go off quicker.

The trowel was a circular 10mm one.

A circular notched, solid bed trowel is fine & is what I use. The notches must be wider than they are deep to give a solid adhesive bed when set but the size always seems to cause confusion; my trowel lays adhesive strips 10mm deep x 20mm wide approx.

The pdf data sheet is very interesting as its different to what it says on the bag! It doesnt mention admixtures on the bag for timber floors. I have tried calling bal but they are shut till next week.

I would be interested to hear what they have to say; to be perfectly honest with you, I’ve used it both with & without Admix AD1 & it didn’t seem to make much difference both when initially laying the tiles or with long term reliability.