Home>Discussions>INTERIORS>Living Areas & Workspaces>How do I remover black mastic from hardwood floor?
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Re: How do I remover black mastic from hardwood floor?

I was looking back at my old posts and figured I'd share how things worked out for me... I was going to go for heat (hair dryer), but it was messy and I was still concerned about the bit still left on the floor interfering with the bond of mortared tile. So what I did was start with an old sc****r and hammer to chip off the thicker chunks of black mastic. Then I used gasoline. The gas melted the mastic pretty quickly, I wiped with a rag then covered with cat litter. It took three cleanings before I was satisfied that I had clean enough concrete for tile to reliably bond too.

I only had about 20 square feet to clean, so this approach got me through. But I'm not sure I'd recommend it. Having the room smell like gas for a few days was tough. But it worked. It's been a few months now and the tiles haven't poped up yet.

Re: How do I remover black mastic from hardwood floor?

Thanks for the information. I think I will pass on the gas. Sounds like gas will melt it, but I have a daughter-in-law who smokes all over the house. She could smoke at the wrong place at the wrong time. I plan to sand and refinsih the floors so I do not want to use any compound which will harm them. There is probably 800 or 900 square feet to remove. Due to planting, trimming, and other outdoor activities I have been unable to return to my project. I still plan to try the "orange" compound. It worked on the 2 square feet I tried but took a long time.

Thanks again for the report.


Re: How do I remover black mastic from hardwood floor?

Use of solvents (aside from water) are very bad for removing 'cutback' from concrete when tiling for a very simple reason; the solvents disolve the cutback and allow it to sink into the slab making the bond of the tile worse, if it bonds at all. Before tiling we always perform a sinple test; wet the slab with about 1/4 cup of water in a few loactions. If after 20 minutes the water hasn't absorbed, the slab needs to be scarified with a diamnodn cup grinder to open the pores of the slab so the thinset can bond.

Aside from pure muscle, one can grind off the cutback with the same diamond cup grinder, usually mounted on a hand held, variable speed, right angle grinder. Use a dust mask, shop vac, and large fan pointed out a window.


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