Ceramic tiling over old Bitumin based adhesives?

Gastines2

How do other floorlayers get on with the problem of tiling on floors that have had either wood block or Marley tiles laid on bitumin based adhesives. For years I have always scraped what adhesive it was possible to remove,scarified surface with a steel rollered Hedgehog and levelled with a coat of latex screed. Then just carried on with normal tile adhesives etc and never had any problems. This includes houses that we have lived in. However ,the bungalow I am now in had very thick bitumin adhesive throughout and for a change,instead of doing the job then reading the instructions afterwards, I took the trouble to contact the screed manufacturers to see what they recommended. I was advised that latex screed will not take on the surface as I prepared it and they couldn't advise any alternative!!!!!
What do other floorlayers do whenconfronted with is problem including the residue left from stuck down carpet?

missile

Last time I laid tiles, I put down thin ply first.

tpt

dont put thin ply down first. IF you do overboard with ply it needs to be at least 12mm and fixed at 200mm centres, which would be very hard to do on a floor like that.

I'd rough it up a bit with sandpaper, prime it with neat acrylic(not pva) bonding agent and then when dry use a flexi adhesive onto it such as granfix rapidset flexi. If you want to be dead sure i'll give granfix a ring for you, let me know.

Gastines2

Thanks Tpt. Obviously on a concrete floor. On a wood floor I always put down marine ply,well fixed. I have also tried a weak PVA wash,still wet and then put the Latex Screed down, all without problems but on phoning the manufacturers they said a definite no.no. but couldn't offer any advise as to an alternative.
Even worse ,many years ago I was responsible for putting Marley Tiles down before I moved onto carpets. Even a problem for carpet fitters as Marley tiles either shatter when gripper is fixed or come loose off the adhesive over the years. Many of us avoided putting the Bitumin right up to skirtings and door frames as it was a bu--er to clean.

tpt

Give granfix technical a call. 01773 607778 ask for tech advice and they will set you straight and, importantly back you if you have an issue.

Once you know what you need they should be able to tell you your nearest stockist, or i can supply you if you are struggling, but usually delivery charges make me more expensive - even if i discount the adhesive.

jcb208

Layed ceramic tiles in my kitchen over a bituim layer after removing marley tiles over 10 years ago never had a problem and still fixed solid now

tpt

Yep i agree, i know of some that have been down ages BUT adhesive has changed lots in 10 years - one of the reasons that PVA is now a big no no is that that it can react with polymers found in new adhesives. Even a lot of standard non flexi adhesives now have a totally different chemical composition. Always worth a check especially as the line is free.