Replacing Existing Floors

Is it possible to remove worn carpeting from a concrete subfloor and then apply a decorative treatment or overlay? You bet, says Harris, but it can be a major undertaking and may require hiring a professional. Here, he discusses some of the challenges, such as disposing of the carpet in a responsible manner and removing any adhesives used to glue down the carpet, which may require the use of harsh chemical strippers. Once the carpeting is removed, you may find tack-strip holes or cracks in the existing floor that will require patching.

As with carpet, removal of linoleum and sheet vinyl from an existing concrete subfloor can be a major undertaking. In addition to the laborious task of scraping off the tile from the floor, Harris explains that you also have to remove the mastics used to glue down the flooring. He cautions against removing tile that contains asbestos because of the potential health hazards. One option is to cover the tile with an overlay.

Removing ceramic tile from a concrete floor can be very labor intensive, says Harris, and may be better left in the hands of a professional. In addition to taking up the tile, you have to remove all the grout. And once the tile comes up, you'll need to scrape or grind the surface to get it smooth and remove flaws before applying a decorative treatment or overlay. Another option is to cover the tile with an overlay (see the video Installing Concrete Floors Over Tile).

Unfortunately, not all existing concrete is a suitable candidate for a decorative overlay. Harris explains the difference between minor flaws that can be successfully covered by an overlay, and major flaws such as wide structural cracks and severe spalling that will require more drastic repair measures. He also shows examples of how to address minor cracks and joints in existing concrete and discusses how you can even "accentuate" cracks and color inconsistencies using stain, to achieve a distressed or rustic look.

Is it possible to install a decorative cement-based overlay right over vinyl floors? Yes, says Harris. You must make sure the vinyl is well adhered to the concrete before installing the overlay. He explains that it's a good idea to ask the material manufacturer if it can be applied over vinyl. If the vinyl is not removed Harris will use expanded metal lathe and staple it to the floor for structural support. The cement-based overlay is poured over the lathe.

Is it possible to install a decorative cement-based overlay right over ceramic tile? Yes, says Harris, but only if the tile is sound and in good condition. He explains how to determine this by conducting a chain-drag test for tile adherence. Other factors to consider:

• If the tile is glazed, it must be scuffed up first to ensure a good bond.
• Before applying the overlay, you must preseal the grout joints so they won't absorb moisture from the overlay. This can result in differential curing and ghosting of the joints through the overlay.
• Ask your contractor if the overlay to be installed is suitable for going over ceramic.

Even wood flooring can be covered with a concrete overlay if you want to change the look or the flooring is in bad shape aesthetically. The main consideration is how much deflection the floor exhibits, which is usually determined by the joist spacing and the thickness of the wood used. Harris recommends hiring a structural engineer to make sure your wood floor can bear the extra weight of the concrete, especially in a second-story application.

Installing a concrete overlay over an existing wood floor is substantially different than resurfacing existing concrete. Harris describes the methods he has used successfully and some of the precautions to take, such as ensuring that the overlay product is suitable for going over wood and stabilizing the floor first to give it enough rigidity.

When installing concrete overlays on existing floor, dealing with baseboards and transitions from room to room can be tricky, since the overlay will add thickness to the floor. Harris takes you on a tour of his own office to show you his strategies for dealing with these issues and how to apply them in your home.