Installing New Tile

Moved to tiling forum.

What kind of floor is under that adhesive? Concrete slab? Wood?

oh'mike said:

What kind of floor is under that adhesive? Concrete slab? Wood?

Click to expand...

Concrete slab

You may be fine---or not---take a long straight edge and see if the old thinset will cause high spots---should be within 1/8" in 10 feet for large format tile (13x13 or larger)

Often the remnants can be troweled right over with thinset as you tile----

A floor buffer with carborundum stones can get that cleaned up fast--rent one if possible.

Not sure how wrong this may be, so let's hope that Mike is still around to tell you it's nuts, but I'm old school (too old school sometimes), so when we retiled our mechanical room I gave my helper (a.k.a. wife) a fire brick, relatively flat with a mildly coarse surface, to knock off the high spots, and it worked great. Once the ridges were knocked down, we cleaned it good, checked it with a straghtedge, as Mike mentioned, and started laying tile. I don't know if the scuffing she did with the brick was absolutely necessary, but I felt better knowing that we had the subsurface relatively flat.