Installing Gypsum Fiber Underlayment

What You'll Need
Tape measure
Utility knife
pH-neutral cleanser
Ring shank nails

When you are looking to install floor tiles you need an underlayment that is strong and flat. It also has to be stable and be able to accept the adhesive for the tiles. The underlayment gives tile a fresh surface for it to rest on. It is always a good idea to choose an underlayment you can work with easily and gypsum is one such underlayment. Many builders do not use it because it is very much like drywall but installing it correctly and knowing where and when to use it a gypsum underlayment is perfectly fine. The article that follows will explain how to install a gypsum underlayment to your subfloor.

Step 1 – Acclimation

Gypsum underlayment, like drywall, is susceptible to the environment that it is in. The boards will swell and contract with varying temperatures. To prevent this from happening you need to get the gypsum underlayment adjusted to the temperature where you are working. Bring them inside two days before you plan to work and make sure you stack them. Placing the boards upright can create a hazard as they can fall down and crush someone.

Step 2 – Clean the Subfloor

You want the gypsum underlayment to have a good grip to the subfloor and so cleaning it is important. Clean it using the pH-neutral cleanser according to the directions on the bottle. This can be done with the mop. You will then want to rinse the floor with plain water and then allow it to dry naturally. If you have vinyl flooring down or carpeting then you will need to remove them to the subfloor. Carpet can be cut off and the nail boards removed. Vinyl tile can be cut and then ripped. You may need to use a putty knife to scrape the tile off. Vacuum the floor before cleaning it and. If there is adhesive left from the tiles; sand it down flush with the floor.

Step 3 – Lay the Boards

Place the gypsum underlayment on top of the subfloor so that the edges butt together. Leave a ¼-inch along the walls. Place as many full-sized boards as possible. If you need to trim the boards to fill open space you will do that last. Measure the space to cover and transfer that measurement to the board. Score the paper with a utility knife and then carefully snap the board along the line. You can then place it. Remember to maintain the ¼-inch distance from the walls. Continue until the subfloor is covered with the gypsum underlayment.

Step 4- Fasten the Underlayment

Start with the perimeter of the boards. Place the nails ½-inch away from the edges and one every four inches. Hammer them in place until the heads are flush with the underlayment. Hammer in more nails within the perimeter every four inches. Check the boards at the seams to make sure they are even. If they are not; sand them down until they are. Sweep away the residue.