Even New Floor Tile Can Contain Asbestos Fibers

February 16, 1991|By Karol V. Menzieand Randy Johnson

Recent columns on dealing with old tile floors drew queries from a couple of readers. Both were considering removing old resilient floor tiles -- one to replace it with other tile, one hoping to find wood flooring underneath -- and wanted to know whether and how to proceed.

The problem with removing old tile, besides its being a messy back- and knee-breaking task, is that even tile very recently put down may contain asbestos. Asbestos fibers can cause lung disease if inhaled. There are two things you can do to minimize the risk: Leave the old tile in place and put down new underlayment and new tile; or remove the old tile using recognized asbestos abatement procedures.

The reader who wanted to put down new tile noted that the old tile, which has been down at least 20 years, was installed over Masonite. Now the tile is cracking over the seams in the underlayment and some of the tiles have spread apart.

This old tile is virtually certain to contain asbestos. Asbestos abatement is regulated differently from state to state. Where it's legal, it can be removed by the homeowner in proper protective gear using proper procedures. In other cases, the work has to done by a licensed contractor. Then the underlayment can be pried up and disposed of.

But this is a case where the old tile might well be left alone, if the added thickness of the floor would not cause serious problems. It sounds as if the old underlayment is loose. It can be nailed down again, right through the old tile, with long ring-shank nails. Then new underlayment (we'd recommended exterior-grade 3/8 -inch plywood, but you can check with the manufacturer of supplier of the new tile for recommended underlayment and adhesives) should be glued and nailed down, also with ring-shank nails long enough to go through the old underlayment. And then new tile can be installed.

The other reader, who hoped to find old wood floors under the tile, should find out first whether there is wood underneath, and if it's worth saving. If the old tile has underlayment, the nails and adhesive used to install it may have hopelessly disfigured the old floor. Or the old floor may have been rotten or patched, and that's why the tile was installed.

The safest way to determine what's under the tile is by examining the underside of the floor. On the first floor it may be as easy as going into the basement and looking up for floorboards. If there are floorboards with a lot of nail points sticking through, there's underlayment. However, some old wood floors were installed with subflooring, in which case the nails will be flooring nails. On upper floors, the best way may be to look at an adjoining wood floor and determine the height difference with the tiled floor. If it's 3/8 of an inch or less, it might be just a layer of tile.

If there seems to be a salvageable wood floor underneath, the safest course is to treat the tile as if it contains asbestos. However, after the tile is gone, the homeowner will still have to evaluate whether the old floor is worth saving.

Another reader wrote from the midst of renovating a 100-year-old row house that he was having trouble nailing furring strips to plaster-over-brick walls and wondered what kind of fasteners would do a better job.

The truth is that nobody has good luck getting furring strips fastened to old plaster and brick walls.

The plaster simply powders, the old bricks are often brittle and the mortar joints are just sand and lime. There's nothing solid enough to hold a nail, and drywall installation over furring is generally unsuccessful.

Some contractors use 16-penny hard-cut masonry nails, predrilled so the nail head doesn't (always) crack the furring strip -- but even that method isn't dependable.

The reader seems to be pretty far along in this process and isn't anxious to start over, so our best advice, which is to frame out or repair such walls rather than furring them, isn't very helpful.

The best we can offer is our system for fastening framing to old brick and plaster walls: using sleeve anchors. (There are a number of trade names for these devices, such as Red Head or Rawl, and you may have to go to a building supply house to find them.)

Apart from the fact that they're time-consuming to install and sometimes fail, they also have a head that is hard to recess into a 1 by 3. The answer is to install another layer of furring perpendicular to the first and install the drywall over that. The second layer of furring can be shimmed out to make it plumb, which would solve another of the reader's problems, uneven walls.

Finally, this reader was concerned about a 1-foot gap between the 8-foot-tall furring strips and the 9-foot ceiling. Quality drywall installation requires catching the drywall on all edges, including the top of the wall, where tape will be applied. In this case, perpendicular strips along the top of the wall would help.

Next: Saving graces.

Mr. Johnson is construction manager for Neighborhood Housing Services of Baltimore. Ms. Menzie is Home Editor of The Sun.

If you have questions, comments, tips or experiences to share about working on houses, write to us c/o HOME WORK, The Sun, 501 N. Calvert St., Baltimore, Md. 21278. Questions of general interest will be answered in the column; comments, tips and experiences will be reported in occasional columns.

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