How to Repair Masonite

Masonite is a common wood siding used for homes.

Masonite is the brand name for a type of hardboard wood siding. It is commonly used as a siding on residences and commercial buildings. Hardboard siding is made of a wood composite consisting of wood pulp and water heated and pressed into the shape of plank. The excess water that is squeezed out results in a stiff piece of siding. Masonite siding is subject to damage from weather or other external conditions, necessitating its replacement.

Things You'll Need

• Masonite siding
• Stud finder
• Utility knife
• Pry bar
• Sand paper
• Measuring tape
• Caulk
• Galvanized nails
• Hammer

Instructions

1. Locate the nearest studs on either side of the damaged portion of Masonite siding. Mark the location of the studs with a pencil.

2. Use a pry bar to loosen Masonite board that sits atop damaged boards. Pry up the board to enable damaged board to be removed. Discard the nails from the loosened board.

3. Use a utility knife to cut the damaged portion of the Masonite board. Drag the blade of the knife from the top of the board to the bottom. Repeat this process until the utility knife has cut through the siding.

4. Place the pry bar at the bottom of the damaged board and work the damaged board loose. Use caution to avoid scrapes or damage to siding below the board you are repairing.

5. Use sandpaper to smooth the rough edges of the cut siding that is still intact.

6. Measure the removed section of Masonite siding and cut a new piece to replace it. Spread a bead of caulk along the cut ends and across the back of the new piece of Masonite siding. The caulk seals patch seams to prevent water leaks behind the siding.

7. Position the new Masonite siding in place. Slide the top edge of the siding under the bottom edge of the siding board, above the area being repaired. This should create a slight overlap between layers of siding. Use a damp cloth to wipe away any caulk oozes out around the edges of the caulking patch.

8. Secure the new piece of Masonite siding into place with galvanized nails across the bottom of the new masonite siding patch.

9. Prime and paint the Masonite repair to match the rest of the siding.

Tips & Warnings

• Cut the damaged Masonite board only where the studs are located. This enables the Masonite siding patch to be securely nailed to the studs.

References

• Servicemagic: Masonite Siding a Stronger Alternative
• Home Addition Plus: Patching Wood Siding