How to prepare subfloor For a successful installation of your hardwood flooring project, the foundation must be solid. In the preparation of subfloor, the crucial components to examine and achieve are: moisture content, structural integrity, and a flat, even surface. Moisture content It refers to the amount of moisture held within a particular material. What's more, moisture content is relevant to both wood and concrete. Concrete is mentioned here because typically, most wood sub-floors are installed on top of concrete slabs. This is particularly true in tropical climates such as Panama, Costa Rica and other Latin American countries in the tropics. Moisture is contained in the wood's walls and nucleus, while every concrete mixture also holds a certain amount of water. Moreover, concrete pulls moisture from the air and ground, making solid wood floors installed over it more vulnerable to moisture, especially when the installation is placed at or below grade. It is advisable to keep both the subfloor and concrete dry prior to the installation of any flooring on top. So the question now is how do make this determination without moisture testing? A moisture meter can come in handy. In fact, for every 1,000 square ft., a minimum meter reading of 20 in subfloor is recommended by the National Wood Flooring Association, while concrete's moisture content should not exceed 4%. Some common moisture content test devices that are subfloor-friendly include Tramex Concrete Moisture Encounter meter, Calcium Chloride test, and Polyfilm test. If the area where the construction is located is not of super low humidity such as all tropical locations like Panama, Costa Rica and other tropical countries, it is advisable to make use of underlayment that is accompanied with a moisture barrier. The order of the materials used typically goes from the bottom on up as follows: concrete, underlayment, subfloor, and hardwood floor. Underlayment is a sort of structural layer of cement, cork, or plywood board, on top of which the flooring rests. Although it is not always essential for flooring installation, underlayment does contribute to leverage the overall performance of your hardwood floors in certain cases. Underlayment comes in rolls and are typically rolled out to cover the entire floor, with each roll's edge to be joined with a special tape. In certain cases, the finished flooring requires a specific type of underlayment. So, check with your flooring manufacturer whether the placement of underlayment would be necessary and useful for your Project. Structural integrity How well your hardwood flooring performs depends greatly on your subfloor's integrity. First, sweep the area and then take a close look. Remove any nails or screw heads. If it is not possible to level and countersink these nails or screw heads, replace them. Walk on the surface. Do you hear any squeaks or detect any spongy or hollow areas? If the answer is yes, it might be due to a weak spot in the concrete below, which should be addressed before the installation proceeds. Typically, the recommended subfloor's thickness is ¾". Double check with the flooring installer so that all requirements regarding thickness and width are met. A clean, flat and even surface Make sure your subfloor is broom cleaned, smooth, and scraped. There should be no wax, oil, debris or paint. Specifically, subfloors should be approximately 3/16 of an inch over 8 to 10 foot span. This means there should be no dips that are beyond 3/16 of an inch within 8 to 10 foot range. When you search for uneven spots, get a flat 8-10 foot plank, lay it out, and mark trouble spots as you move it across the entire floor. Don't panic if you find some minor bumps on the subfloor. They can be sanded down using a rented or hand-held orbital sander. Remember to wear protective goggles and a dust mask while sanding, as the work produces a lot of dust. In terms of dealing with dips, gouges and imperfections, you can fix them by using a leveling compound made of cement. You would mix it, following the manufacturer's instructions, and patch the subfloor with it. Mixing floor patch requires similar consistency to mixing pancake batter. Follow these steps to floor patch evenly: Firstly, take the board you are using as a straight edge Next, apply the patch that is sufficient to fill the target gap or gouge Lastly, with one person on each end, pull the board back and forth over the target area for the patch to be spread. This is called screeding. Let the screed dry completely after filling all the gaps. Check for flatness and sand if necessary. Note: Avoid using large areas of floor patch if your hardwood floor is to be nailed and stapled, as the patch will crack. Visit Wooderra.com for more woodworking related guide.
