• Aspen Construction

How to repair horizontal lap siding

Not every home is a perfect candidate for new siding; sometimes a few repairs will do the trick. Here's a quick how-to for some minor repairs

Spokane and Coeur d'Alene Siding replacement Contractor

When it comes to replacing horizontal lap siding, the process can be somewhat laborious because of the size of the pieces and their weight. If you are replacing a piece of vinyl siding the weight is not a problem, but the length can be awkward.

What we’re going to discuss is going to be how to replace a piece of James Hardie ColorPlus lap siding or a piece of regular James Hardie plank lap siding. Hardieplank siding or Hardiplank siding - however you choose to spell it. Repairing James Hardie Fiber Cement siding can be a daunting task because of both it’s weight and length. The horizontal lap boards weigh 2.3lbs per square foot, so a 12’ stick can weigh just over 15 lbs based on an 8.25” height.

I suggest replacing the entire piece of siding even if only a foot or two of it it is damaged. The reason for this is simple; simplicity and accuracy. If you try to cut only a foot or two out you’ll have to try to cut the bad board perfectly square on both ends and then cut the new board to fit precisely in your fresh hole. Good luck with that. You might end up with a bigger mess than you had to begin with!

Assuming your hardiboards are blind nailed (meaning the nails in the top of the plank are hidden under the board above it) the first step is to slip a flat pry bar under the bad board at either end. Be sure you use something like a piece of scrap board or thick cloth to ensure you don’t damage the paint on the board beneath the bad one and begin to pry the board out from the wall. The fiber cement siding will pull through the nails and pop off - this is where you’ll want the help of a friend to hold the falling board up as you continue to work down the wall. (Hint; your nails should be in about every 16” though sometimes every 24”.)

Once the new board is off, you’ll need to get back under the board above and remove the nails from the wall or drive them into the wall flush with the wall. To drive them flush, I put my flat bar up under the upper hardieplank and on top of the nail head. Then, place a wide piece of plywood or 2x4 over the plank and hit it with the hammer. The flat bar on the nail head will drive it deep and the plywood or 2x4 will protect your finished fiber cement siding.

Once the nails are in (or out) you’re ready to insert the new piece. With James Hardie plank siding the boards have a recommended overlap from the board above of 1.25”. And you’ll need to nail down from the top 1”. Make sure you’re nailing into studs every time and drive one nail every stud down the length of the board to ensure it will stay secured to the wall.

With James Hardie ColorPlus lap siding it is not advisable to caulk the butt joint (that’s where two boards meet), however, with a board you’re going to paint yourself, you may apply caulk, though it’s not necessary.

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