How do you level your floor?

Answer 1

Leveling a floor requires determination of why the floor is unlevel to begin with and what types of floor coverings did you want to use? Structural causes to uneven floors represent a larger more complex series of questions and resolves then is practical from a posting. If you have movement from joists or upright supportive beams, or sinking forms/footings of concrete talk to a contractor or professional! If you simply want a cosmetically level floor then I will try to help. Different types of floor coverings require different tolerances of levelness in the sub floor/substrate. Carpet stretched over underlay (carpet cushion) is by far the least demanding type of floor covering. Sheet Vinyl needs to be installed over a substrate that is porous, will not move around, pass moisture, and be smooth and consistently room temperature. Vinyl tile is the same as Sheet vinyl but less tolerant to unevenness. Ceramic tile is very demanding about firmness, non-moving, evenness, porous. Hardwood (solid) requires a substrate that will accept fasteners securely, stable humidity; levelness is required as the finished installation will only look as level as the substrate it is nailed to. Hardwood (glue down) requires porosity, dryness, normal humidity, levelness. Hardwood/Laminate (Floating installation method) requires normal humidity, levelness within 5/16" across 8-10 ft. Leveling compounds are available to "feather" out small cracks (1/8" square) all the way to 3" thickness. Leveling compounds are typically made from Portland Cement and modified with a polymer. As you increase the required thickness of leveling, the Portland cement is processed with more of a "grainy" shape to increase the compressive strength ("compacted sand"). A latex/acrylic primer coating should be applied to the substrate when leveling areas in excess of 1/2" in thickness. Simple leveling is applying up to 1/8"per application to a maximum thickness of 1/2". Full self-leveling compounds are used for areas greater then 1/2". These compounds can be very expensive. Leveling compounds should be applied with normal room temperatures before/during/after installations. The additives used to increase compressive strength are very strong in odor and proper ventilation should be used. The curing/drying time on various leveling compounds depends on thickness of application, strength of mixture (acrylic), room temperature; amount of mixing/troweling compound is subjected to. The mix ratio of powder to water/additives is very important. Exact mix ratios must be used or curing/drying may not develop properly and is very difficult to remove. Using an 8ft long level or straight 2' x 4' go over entire area and mark low spot perimeters with a piece of chalk or pencil. Mix up only enough compound that you can actually spread within 15-20 minutes. A wide, paint trowel is inexpensive and works great moving the compound around. With larger applications a "screening" board also works great. Remember self-leveling doesn't mean self spreading! Sanding trowel marks and ridges is required when gluing down sheet vinyl or vinyl tile. Also allow 24-48 hours drying time first. If your substrate is very unlevel and structural changes are not possible, you may want to use"D grade" plywood to "build up" the bulk of the low areas before applying the leveling compound. Plywood is always less expensive then compound. Do not underestimate the spread rate of the compound as a 50lb bag doesn't cover as much as you think @ 1/2" thick! Always check for door threshold clearances and appliance clearances prior to pouring. Some products are truly a professional-use only product. Always read the prep and working time before you purchase!