Replacing Rotten Hardboard Siding on Your Home

Rotten hardboard siding on house before replacement with fiber cement siding.
Rotten hardboard siding before replacement with fiber cement siding.

Hardboard lap siding has been used on homes for years because it mimics the look of wood siding but is much less expensive. One of the disadvantages of hardboard siding is that exposure to water can cause it to deteriorate over time. This is most common on the bottom few courses near the foundation.

If you have this problem, you might want to consider replacing the rotten courses of hardboard siding with more durable fiber cement siding. Fiber cement siding is available in the same look and dimensions as hardboard siding but is more resistant to water damage. It also doesn’t cost much more than hardboard, and it’s a fairly easy to make the repairs yourself.

Tools Needed:

  • Tape measure
  • Hammer
  • Chisel
  • Pry bar
  • Circular saw with masonry blade
  • Caulking gun
  • Paintbrush

Materials Needed:

  • Plywood sheathing
  • 15-lb. builder’s felt or housewrap
  • Fiber cement siding
  • Hot dipped galvanized or stainless steel nails
  • Paintable exterior caulk
  • Exterior paint
Danny Lipford replacing hardboard siding with fiber cement.
Danny Lipford replacing hardboard siding with fiber cement.

How to Remove and Replace Siding:

  1. Remove Damaged Siding: Remove the deteriorated hardboard siding using a pry bar and chisel, being careful not to damage the good siding above it.
  2. Replace Rotten Sheathing: If needed, replace the sheathing behind the siding using 1/2” plywood covered with builder’s felt or housewrap.
  3. Cut Fiber Cement Siding: Cut the fiber cement siding to length. Always wear an approved dust mask or respirator when cutting fiber cement.
  4. Install Fiber Cement Siding: Nail the fiber cement siding in place so the rows are consistent with the rest of the wall. Fiber cement siding can be blind nailed near the top of the siding to eliminate exposed nails. Nail the top course of fiber cement siding through the lower course of hardboard siding.
  5. Caulk and Paint Siding: Caulk the end joints in the siding, then paint the siding with quality exterior paint.

Watch this video to find out more.

Further Information

Danny Lipford: Hardboard lap siding like this has been used on houses for many, many years because it looks like wood but it’s a lot less expensive. But one of the drawbacks with using this kind siding is if it gets wet and stays wet, it can deteriorate very quickly.

In fact several of the pieces of the siding had to be replaced here on the driveway side of the house, as well as behind the house where the deck meets the house. That’s where the rain is constantly falling back against the house, keeping it wet and causing the siding to rot.

Now, we replaced the siding with a different type of siding called fiber cement. Fiber cement siding is resistant to this type of decay and is available in the same dimensions and patterns as the hardboard products, so you don’t have to replace all the siding on the house, just the pieces that are damaged.

Now, the process is fairly simple. You remove the old siding carefully without damaging the pieces above it. Now, underneath this siding, we also had to replace the sheathing, so we used half-inch plywood and a layer of builder’s felt.

The fiber cement siding is nailed in place so the rows are consistent with the rest of the wall. Because cement is the largest component of the siding, it’s hard on saw blades. So if you’re cutting much, a masonry blade is a great idea.

After installation, you caulk and paint it like any other siding. And the homeowner here decided to even change the color. And another great thing, it costs about the same as hardboard siding.


  1. We are looking at using hardiplank on the outside of our house. Debating on doing the entire house or just repairing sections with it. Have you heard that if you patch areas that the sections next to it will deteriorate quicker due to the moisture diverting to them as the moisture barrier behind the hardiplank is better?

    Thank you!

  2. I have Masonite siding – about 35 years old now. Years back i saw that it was starting to deteriorate, My first reaction was to take a good caulking and mix in in a pail with water – kind of like thick cream. I then painted all of the lower edges on the board before painting the house. Where the boards were real bad I broke off the worst of it and covered the whole bad boards with ivory colored aluminium. (I have access to an aluminum brake press) That was about 5 years ago. This year I am obliged to repair two more small areas. This time I am going to use 3/8 plywood to make siding and cover them with aluminum. I will probably have to nail through the siding into the studs and caulk the nail heads but I am determined to keep the siding for as long as possible.

  3. I have areas around dormer windows and where siding meets roof that have deteriorated. The last roofer said he could not find any hard board or fiber cement siding that is the same narrow size. Where can I find different sizes of older (1989) hardboard?? Wonder if is cheaper to side about 1/3 of the brick house and forget the repair??

  4. I have same damage on siding around house and damage same on molding trim on windows.Plase can you fixs my problems.

    • Hi, Jozo, features home improvement advice from the nationally syndicated TV show “Today’s Homeowner” and its experts.
      We don’t offer information on individual home builders and suppliers, or provide direct construction services, but we encourage checking your local phone listings for this information.
      Good luck, and thanks for your question!

  5. can you help with a contractor in the Columbus Ga or Phenix City Al area that can replace siding on a house built in 1991.

    thank you for you help

    • Hi, Larry, features home improvement advice from the nationally syndicated TV show “Today’s Homeowner” and its experts.
      We don’t offer information on individual home builders and suppliers, but we encourage checking your local phone listings for this information.

      Thanks for your question, and good luck!

  6. I’m thinking of putting pavers over my existing concrete patio. In some spots of the patio, though, where the patio meets the foundation the thin pavers will be very close (if not actually touching) the fiber cement and trim. Does this present a problem? There is a bit of a small roof overhang in these areas. Does there need to be some sort of space between the top of the paver and the bottom of the siding and or trim? The two masons I have bidding on the job said it shouldn’t be a problem. Would it help if I repainted or sealed the bottom of the siding prior to the paver installation? Thanks for your help.

    • Hi, CC,
      Fiber cement siding manufacturers recommend at least one inch of space between the siding and a concrete slab (or any other horizontal masonry surface like pavers.)
      While fiber cement is much more durable than other siding materials, it will deteriorate if water is held against is constantly.
      Thanks for your question!


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