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Flooring and Carpeting/Install tile over old asphalt mastic


Hello, we bought an older farm house last year and are in the process of tiling the kitchen floor.  We removed two layers of "layer cake" flooring (by this I mean there was a layer of vinyl then 1/4" plywood then vinyl then 1/4" plywood),  only to find another layer of tile adhered directly to the original hardwood floor.  We removed the final layer of tile to find that it was placed with an asphalt mastic.  we have scraped the mastic off as much as possible but it is not completely removed.  My question is can we tile directly over the mastic?  The hardwood is solid and there is a subfloor below that, consisting of 1"x 4" boards.  We would prefer not to install a backer board as the difference in floor heights to adjacent rooms would be nearly 3/4" when the tiling is complete.  Thank you.


You can not install tile over wood floor directly. And the mastic makes it even more precarious regarding a good bond.

In the old days a layer of plaster lathe wire was laid down and fastened to the wood floor and a 3/4" -1" bed of mortar was floated on top of that, once dried, then the tile was laid. a very stout and excellent method ...if you ever tear one up you will know.

Since the cement board has been around for many years it is easier for DIY's  and if directions are followed a very sound system. I have used it repeatedly.

They offer the cement board in 1/4" and 1/2" by HARDI BACKER and I prefer that brand due to the density. The wonder board is too fragile and crumbles when handled roughly. I don't like the way it takes a screw compared to the Hardi product.

Since you tore up so many layers I would assume that a 1/4" backer board and a 1/4" or 3/8" tile would not be a difficult transition.

What type of new tile / stone are you planning to install ?? Maybe I could offer transition suggestions??


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20+ years flooring installation ...carpet,wood,tile and vinyl. Residential and commercial. I do not sell the products , just install what ever the shop / customer has purchased. I actually love seeing the finished project completed and it gives me great satisfaction to help others acheive that goal. If I don't know the answer I will say so, and then I will recommend another expert for you. I may even research the subject and answer to the best of my ability ...including links to my sources. I wish you all success Chris


20 years as an independant contractor

H.S. diploma A.S. agriculture Mt San Antonio JR. College

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