Tiling over a concrete floor which has already had a coat of PVA

[Harry89]

Hi

I have had specialists in to remove vinyl floor tiles containing asbestos leaving behind the bitumen adhesive (also containing asbestos) which they have encapsulated by giving a coat of PVA. What is the best way to go about tiling the floor? Its a concrete floor mostly covered in bitumen with a coat of PVA on top which I will tile with either a ceramic or porcelain tiles.

-will self levelling compound adhere to the PVA?
-will flexible tile adhesive adhere to the PVA?
-will a tile primer over the top help?

Any advice would be much appreciated.

 

[Time's Ran Out]

If you think there is asbestos in the bitumen and you paid specialists to remove it - GET THEM BACK!!
It's against the law to do it yourself and there's nothing you can do till it's removed.

 

[Harry89]

Thanks for your reply John, the quote I had from the asbestos company was only to remove the tiles and encapsulate the adhesive which is what they've done, they are a reputable company and I'm happy with what they've done. My main concern is will it be ok tile over the PVA/ bitumen? If so what is the best way to prep the floor? Removing the bitumen is not an option as it will be far to expensive.

 

[Time's Ran Out]

Unfortunately I'am not qualified in the handling of asbestos, but PVA would normally break down with the addition of a water based adhesive.
I would suggest you contact one of the major tile adhesive manufacturers technical departments for definitive advice.

 

[Harry89]

Thanks John I'll do that

 

[Tile Shop]

Would be interested to know who you speak to and what the outcome is on this one.

 

[Stevev]

Hi

I have had specialists in to remove vinyl floor tiles containing asbestos leaving behind the bitumen adhesive (also containing asbestos) which they have encapsulated by giving a coat of PVA. What is the best way to go about tiling the floor? Its a concrete floor mostly covered in bitumen with a coat of PVA on top which I will tile with either a ceramic or porcelain tiles.

-will self levelling compound adhere to the PVA?
-will flexible tile adhesive adhere to the PVA?
-will a tile primer over the top help?

Any advice would be much appreciated.

Just asking, how does one know that vinyl tiles has asbestos? what made you suspect they had asbestos in them?

many thanks

 

[ExplodingPudding]

Pretty sure that the Bitumen would blow the floor in the long run?

 

[Matt Bott]

Pretty sure that the Bitumen would blow the floor in the long run?

Like an exploding pudding ?

 

[Ajax123]

Thanks for your reply John, the quote I had from the asbestos company was only to remove the tiles and encapsulate the adhesive which is what they've done, they are a reputable company and I'm happy with what they've done. My main concern is will it be ok tile over the PVA/ bitumen? If so what is the best way to prep the floor? Removing the bitumen is not an option as it will be far to expensive.

whilst you are happy that they have fulfilled their contract i am not certain they have applied due dilligence and fullfilled their duty of care. if they knew you were going to tile the floor they should have highlighted the fact that PVA is not suitable to tile over. also, encapsulation implies temporary in the respect that if you tile the floor then at a later date you or a new house owner after you takes up the tiles you are potentially exposing them or yourself to asbestos which could be pproblematic particularly if you want to sell the house. have they given you any safety certificationmor assurance. many a reputable company routinely do poor work.

 

[Ajax123]

in the

Just asking, how does one know that vinyl tiles has asbestos? what made you suspect they had asbestos in them?

many thanks

during the 1940's and right up to the early 80's some tiles were made using asbestos. they were used extensively in council housing so if you have a councli house with the old style marley tiles on the floor and it was built before about 1980 there is a good bet they contain asbestos. it is possible to proove under a microscope but the reality is that people operate under the law of averages as it is likely they do rather than deffinite. the thing is though with asbestos it is not dangerous unless you start messing about with it, e.g. drilling cutting or snapping it... or chucking it on a bonfire... if these tiles are on the floor my opinion is that it would be better to come up with a solution whereby they can be left in place but that doesnt sit well with tiling. lots and lots of asbestos has ben removed un necessarily over the years. it is not illlegal to do this yourself but disposal is difficult. some local authorities still assist by offering special bags and advice and where i used to live there was a tip that handled asbestos waste under very strict rules. nevertheless it is probably better to get a professional acresditted company to deal with it for you if you aRe not sure

 

[NZ_Tiler]

This is from an old member, sWE, I think it's a pretty good explanation.

PVA and Cementious Materials

I hadn't even heard of using PVA for anything tiling related before I came on here. Thus, I read up on it, and here follows my findings:
PVA stands for polyvinyl acetate, and it is a rubbery synthetic polymer. It is commonly emulsified in water and used as glue. Many know it simply as "wood glue", or "carpenter's glue".
Cementious materials, such as many tile adhesives and grouts, or other materials which contain cement, such as concrete, are alkaline. Simplified, that means they have a high pH.
Alkali slowly attacks polyvinyl acetate, forming acetic acid, which has a low pH. Cement doesn't dry per se; it cures through hydration, which means it binds the water you mix it with chemically. This causes the pH of the substance to rise dramatically. Introducing an acid negates that process to some extent, preventing the cement or conrete from binding all the water it needs to harden properly.
It is hydrtion which gives cement and concrete products strength, and holds them together. Without this process, it would merely be the powder you started with.
The acetic acid which is formed when cement and PVA comes into contact, either through mixing them, or "priming" with PVA, will continually free the water bound in the cement, and that will weaken the bond and/or integrity of the material. The effect is accelerated if the material is subjected to moisture, which is more or less always the case.
PVA isn't water resistant. It becomes slightly live when exposed to moisture, and this in combination with the exposure to alkali, accelerates the forming of acetic acid. PVA which is marketed as "water resistant" or "exterior grade", has additives which makes them water resistant, but they're not alkali-resistant.

 

[Matt Bott]

Wow that is really helpfull

 

[Dan]

We have the perfect combination of tile and flooring related geeks.

We'd give NASA a run for their money building rockets if we had the time eh