How to Use Masonite as a Wall and How Do I Cover the Seams?

Jeannine Lowe

Masonite is a product used most often as exterior siding, but also is used for other projects such as interior wall, underlay for flooring or shelving construction. Masonite is made by the Mason method, invented by William H. Mason, by taking wood chips and blasting them into long fibers using steam.

Masonite is a durable material to use in wall construction.

The fibers are then formed into boards or sheets. Masonite sheets are available in different types and grades, and are a good alternative to traditional sheetrock wall construction material. It is relatively inexpensive, durable and can be painted. With the proper tools and materials, you can construct a wall using Masonite and cover the seams producing an attractive look for your home.

Masonite for Wall Construction

  1. Measure and cut the Masonite siding with a circular saw to the prescribed area that you are trying to cover. It's good to construct the building length and width so that a minimum amount of cutting is necessary since the sheets are 4-foot by 8-foot long. A height of 8 feet and a length and width divisible by four will save on materials.

  2. Hold the Masonite siding in place and use the portable drill to install four 1 1/2-inch drywall screws. If someone is available to help you hold it in place, the procedure is much easier. Start at the top and install the 2 top drywall screws so that it will be held in place. Next,install a total of 4 1 1/2-inch drywall screws down each side, top and bottom.

  3. Place the next 4-foot by 8-foot Masonite sheet as tightly as you can against the sheet installed in the prior step. Seams should be close enough together that you can barely see them. Install four 1 1/2- inch drywall screws on each side, top and bottom to secure the Masonite siding in place.

  4. Repeat Step 3 until all sheets are hung in place.

Covering a Masonite Wall Seam

  1. Locate the seam between two Masonite sheets. Apply a thin bead of clear silicone or caulk down the seam.

  2. Use the trowel to smooth out the silicone, so it fills the seams.

  3. Fill any exposed nail holes with silicone or wood putty.

  4. Choose a desired paint and use a paint roller to cover the silicone applied to the seam and nail holes.

  5. Tip

    Take correct measurements to avoid wasting Masonite material. Masonite can be painted with Interior or Exterior paint. Moulding material can be used to cover seams in a wall. Purchase or rent a nail gun to will make the moulding installing procedure faster. Allow silicone to dry completely before painting to ensure it expands to fill all seams.


    Always cut Masonite in a well-ventilated area.