Skim coat accomplishes much of what its name indicates. It is a coat of a cement product that is skimmed over the existing flooring to provide a smooth and level floor surface. This surface can then be used as a base for vinyl, wood or tile flooring. While the process of applying the skim coat is rather involved, it can be accomplished by a dedicated do-it-yourselfer.
Preparing the floor
Any loose surfaces, dust or dirt must be removed from the floor before attempting to install the skim coat. This may involve using a wire brush or some other tool to free any materials from the floor. The area should then be thoroughly swept or vacuumed to remove the materials.
Installing the skim coat
Mix the skim coat according to the package instructions and prepare it for installation. Wet an area of the floor that can be coated with the skim coat before it dries. A hand-pumped spray tank can be used to wet the floor.
Some skim coat materials are installed in two coats. Spread the first coat using a squeegee; this simply coats the floor. Allow to dry. Use paint brushes to apply a layer of the skim coat in corners where the squeegee can't reach. Allow the entire first coat to dry. Drying times will vary depending on the manufacturer of the skim coat.
Finishing the project
Mix the second coat of skim coat according to label directions. This batch of skim coat is often mixed thicker than the first coat. The floor is again wet with a sprayer before the skim coat is applied.
Apply the second layer with trowels rather than squeegees. Pour some of the skim coat on the floor and work with hand trowels. The ideal depth of the skim coat is 3 mm (1/8 inch). Experiment with the trowel while attempting to create a smooth and uniform surface.
Continue to wet areas of the floor and apply the second application of the skim coat to the wet areas. Work the edges where the new areas intersect with areas of the floor previously worked. Make sure these joints are as smooth and level as possible.
Drying times vary with the manufacturer. Some products are ready for installation of flooring in less than two hours while other products need to dry overnight.