Repairing Hardboard Lap Siding

If needed replace the sheathing behind the siding using 1 2 plywood covered with builder s felt or housewrap.

Repairing hardboard lap siding. Check the siding panel for molds holes or any damage. Make sure to scrub only the compromised area of the siding so that the structure remains unaffected. Use shims to lift the boards so you can easily get at the one you re cutting. 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.

When washing allow it to dry completely for a day or two before treating or curating it further. Remove the damaged siding panel using a claw hammer and extract the nails left on the wall from the old panels using tin snips. You might notice bulging along the bottom edges a loose layer or soft. Immediately fill holes with a flexible all purpose filler such as pre mixed bridging and patching compound following label directions.

Be sure to stagger the joints see photo 1. The siding panels nearest to the ground are usually the first to mold. Promptly repair holes in masonite hardboard to prevent moisture from further permeating the siding and compromising its structural integrity. Repairing hardboard siding if water seeps into joints between hardboard panels or penetrates through small holes it will cause the panels to deteriorate.

Most hardboard siding is 7 16 in. Fortunately you can repair masonite hardboard siding with wood putty. If you can see black marks or streaks anywhere on your masonite siding it is a sure sign of being compromised by water. Remove the deteriorated hardboard siding using a pry bar and chisel being careful not to damage the good siding above it.

Use a 4 foot level to check and then hammer in another nail. Thick so set your blade depth carefully to avoid cutting into other courses. Finish the cut with a sharp utility knife. Holes are a prominent problem with masonite siding.

Be sure the top one goes through both boards.