Looks like we're installing ceramic floor tile in the living room. I've
done plenty of tile work before. Tub surrounds, custom showers, kitchen
counters & backsplashes, but never a floor.
Underlayment is 40-yr-old concrete slab. We're pulling up old linoleum
floor tile squares from the 60s. These were adhered to the slab with
We intend to use thinset to lay the ceramic tiles but don't know if we
should attempt to remove the old asphalt mastic first, down to bare
concrete. This is NOT an easy or non-messy job. Size of the area would
require several gallons high VOC and highly flammable solvent to remove
the asphalt. (I should know. I've done this job before, too.)
Can we apply thinset & tile over the old asphalt mastic?
We appreciate knowledgeable answers from experienced individuals.
Here\'s some of my work:
You would need a polymodified thinset.
Your floor would be as strong as the old asphalt mastic.
If you remove to bare concrete, then you would not need the polymodified.
I am a profesionall tile layer, I recommend bare concrete.
Thanks, Troy. That puts a name on what I need to do the job one way.
I saw some stuff at HD today; Jasco Sealer & Adhesive Remover
that is advertised to remove old mastic. Sure sounds better than a 5
gallon can of lacquer thinner.
Ever used this stuff or similar?
Here\'s some of my work:
A 40 year old slab will be very stable.
Not _any_ polymer modified thinset will do. It must state on
the bag that it will adhere to "Cut-back" adhesive.
In that circumstance I would use a product called
Laticrete 333. (made by Laticrete of course).
It is a liquid which you mix with non-polymer modified
(plain ol') thinset. It makes the strongest, stickiest
thinset I've ever found.
If you can't find Laticrete 333, be sure to look carefully
on the bags of other thinsets to be sure it sticks to
NEVER trust the sales person...they have no freekin idea
what they're talking about. The chemists who create the
products, and the companies who guarantee them, are
a little smarter than the know-it-all store employee.
There are multiple thinsets for many different applications.
It is amazing to me that people will trust the dopey guy
working the 'tile department' that day, when the bag of thinset itself
has very specific printed information on it.
After scraping off all loose adhesive, and washing the
floor with clean water, skimcoat the floor with
a thin layer of the correct thinset, pressing the skimcoat in
with a flat trowel. Pressing or forcing the thinset into the floor
helps to create a good bond. Let this dry 24 hours and you'll
have a strong thin coat of material over that adhesive that
won't want to let go. Then you can use any polymer modified
thinset to lay the tiles.
Two thinsets (of many I'm sure) that I know of for this specific
Bostic's D-70 ProFlex Thinset Mortar
Roberts' R-Flex III Enhanced Polymer Fortified Thinset Morter
and... a reading link for Frank:
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