A bitumen dilema!

[MICK the Tiler]

What can happen when laying over bitumen (Blackjack) is a chemical reaction can take place between the two part flexy addy and the hydrocarbons within the blackjack causing the bitumen to crystilize under the addy and once the crystals begin to form they expand and blow the tiles away from the floor. Isolating the blackjack with a primer might work provided you don't srcatch it whilst trowelling on the addy overboarding or mechanical removal would be the best option IME. another issue you may encounter is bleed through. The bitumen will bleed through the grout and the tile if it is porous like stone sending your expensive tiles a mucky brown colour.

If there is a adhesive manufacture out there that will gladly accept a warranty claim if there adhesive fails if it is used for installation over bitumen........................... I'd like to see that.

 

[GazTech]

We @ BAL offer no warranty, but if bitumen is very thin as in from the rear of thermoplastic or Marley tiles, acrybase leveller over is OK prior to fixing. Careful not to remove bitumen if it is being used as a DPM....Gaz

 

[MICK the Tiler]

Do we know if Andrew's "Blackjack" is indeed a thermoplastic Gaz this is much more stable and would be ok to fix to, but as he has tried to remove some with white spirit and it went all gluggy i'm tending to lean towards a bitumen based substance. What do you think Gaz?

 

[GazTech]

I reckon a piccy would be handy....

 

[Branty]

As has been said, no adhesive manufacturer will guarantee there adhesive over flooring bitumen.
Yet many say 'I've done it tons of times no problems', I too was one of them. It's no surprise to me that the only post from a fixer, with the correct sound advice, is one from another country.
Why are we so happy to keep fixing the way 'we've done it for years'?
If an adhesive company says you cant tile that substrate, it must be for a reason. I mean, they want to sell as much adhesive as possible.
It's down to us a professional tile fixers to find out why the adhesive companies won't recommend fixing onto certain substrates. If every bitumen floor was OK to tile onto, then adhesive companies would recommend it to fix to.
As I said, Ive fixed onto bitumen, done it in my own house (2years later still down), but I now know this is not correct, as I now understand why we shouldn't do it, I won't do it again. Lets hope I get lucky with my own floor, and don't have to rip it up.

 

[Branty]

Just out of interest james...where does it say in BAL literature that there products will not adhere to adhesive residue please....

Does it have to?
If you call BAL technical, they'll tell you why.

 

[Sully]

What a dilemma - I am starting on just such a floor tomorrow in a domestic situation. A very fine layer of bitumen under a laminate underlay. I'm hearing what you are saying BRanty and I'm also noting that Gaz is saying that acrybase leveller would be 'ok'. Loads here have done it with success. My option is to mechanically remove it and line up a painter & director and a team of cleaners to clear the mess after me or take that risk..........and run with the leveller.

Guess I'll just have to sleep on it.

Andrew

 

[TilingLogistics]

Mechanically removing Bitumen is a relatively easy task if you have or hire a floor scrubber

Kev

 

[grumpygrouter]

I had advice from Ardex tech support a couple of months a go regarding a very similar problem. I was given 2 solutions by them 1) if the residue is solid, i.e not flaky then you can prime with Ardex P82 epoxy primer and then tile (I was using Ardex 7001)
2. lay a skim coat of Ardex Feather Finish and allow to set, than tile as above. I chose the second option as it had a faster turn round time, Everything worked perfectly and I have had no indication of any problems from my customer.

Ps - I have a brand new set of P82 primer in my garage if anyone wants to buy it!!

 

[MICK the Tiler]

Will they warrant the adhesive Grumpy after following there advice? Will they give it to you in writing?

Not trying to be smart, Ardex are just one manufacture down here who are willing to step up to the plate on the tricky jobs but leave you on your own when things turn sour.