Repairing Hardboard Lap Siding

Holes are a prominent problem with masonite siding.

Repairing hardboard lap siding.

Immediately fill holes with a flexible all purpose filler such as pre mixed bridging and patching compound following label directions. Promptly repair holes in masonite hardboard to prevent moisture from further permeating the siding and compromising its structural integrity. When washing allow it to dry completely for a day or two before treating or curating it further. Use a 4 foot level to check and then hammer in another nail.

Remove the deteriorated hardboard siding using a pry bar and chisel being careful not to damage the good siding above it. Then hammer away on the rest of the board. Use shims to lift the boards so you can easily get at the one you re cutting. Remove the siding panel that is damage and install a fresh hardboard siding panel.

Be sure to stagger the joints see photo 1. The siding panels nearest to the ground are usually the first to mold. Finish the cut with a sharp utility knife. Make sure to scrub only the compromised area of the siding so that the structure remains unaffected.

Most hardboard siding is 7 16 in. Remove the damaged siding panel using a claw hammer and extract the nails left on the wall from the old panels using tin snips. Fortunately you can repair masonite hardboard siding with wood putty. Repairing hardboard siding if water seeps into joints between hardboard panels or penetrates through small holes it will cause the panels to deteriorate.

If you can see black marks or streaks anywhere on your masonite siding it is a sure sign of being compromised by water. Be sure the top one goes through both boards. If you re replacing more than one board in a run simply hammer a nail into the top corner to support it and then move half way down the board. You might notice bulging along the bottom edges a loose layer or soft.

Check the siding panel for molds holes or any damage.