How to Repair Masonite Wood Siding

Patch and repair masonite wood siding.

Masonite boards are fabricated from wood fibers, wax and other resins through a process of heat and pressure. This durable siding looks like lumber, yet does not swell, shrink or blister like conventional wood. However, the siding is very susceptible to moisture and weathering. Some masonite boards fabricated between 1980 and 1998 are not properly compressed and installed, causing the siding to rot, buckle and deteriorate. Fortunately, certain supplies are effective at patching and repairing damaged masonite siding.

Things You'll Need

• Pencil
• Utility knife
• Pry bar
• Hammer
• Reciprocating saw
• Measuring tape
• Masonite siding section
• Exterior caulk
• 2 galvanized nails

Instructions

1. Make a pencil mark on both sides of the damaged section of siding. Line up the marks over hidden stud walls.

2. Cut the wood siding clapboard through the pencil marks, using a utility knife. Make several downward strokes, to thoroughly cut through the siding.

3. Loosen the nails on the siding directly above the damaged siding, using a pry bar and hammer. Remove the loose nails with the pry bar.

4. Insert the pry bar underneath the bottom of the damaged siding section, without damaging the siding directly below. Cut the nails on the backside of the damaged siding, using a reciprocating saw.

5. Remove the damaged section of siding. Measure the damaged section of siding with measuring tape.

6. Cut a new piece of masonite siding section to match the measurements of the removed damaged section, using the utility knife. Apply a bead of exterior caulk over the back of replacement siding patch.

7. Place the new siding patch where the damaged siding section once was. Slide the new siding patch up underneath the siding directly above, so that the siding above is slightly overlapping the patch.

8. Hammer two galvanized nails into the bottom part of the siding directly above the patch, using the hammer. This will secure the siding patch as well.

Tips & Warnings

• Apply paint or stain to the siding patch, if the patch is a different color than the rest of the siding.

References

• Service Magic: Masonite Siding - A Stronger Alternative
• Home Addition Plus: Patching Wood Siding