How to Replace Damaged Hardboard Siding with Fiber Cement

Replacing water damaged hardboard siding with durable fiber cement siding.
Replacing water damaged hardboard siding with durable fiber cement siding.

Water from rain or sprinklers can damage hardboard and wood siding over time, causing it to rot or deteriorate. This usually occurs on the bottom rows of siding near the ground, or on siding that adjoins a roof or chimney.

To remove and replace damaged siding:

  1. Use a pry bar to remove the damaged siding.
  2. Remove any nails from the top piece of good siding.
  3. Cut the fiber cement siding to length (wear approved dust protection).
  4. Blind-nail the fiber cement siding in place, starting with the bottom piece.
  5. Face-nail the top piece of fiber cement siding through the old siding.
  6. Prime and paint new siding to match the old.

Watch this video to find out more.

Further Information

Replacement is the only option for rotted, hardboard lap siding. However, you don’t have to replace it all, just the damaged pieces, which are usually near the ground or adjacent roofing.

First, pry the damaged pieces off the wall using a crowbar. As the bottom of each board comes out, you can pull down on one end of it and free it from the nails going through it and the row above. Occasionally there will be nails left behind under the last good row of old siding, which have to be cut or removed so the new siding can go in.

Fiber cement siding is a great replacement because it easily matches hardboard profiles, but it won’t ever rot or be eaten by termites. Fiber cement is usually blind-nailed, which means the nails go in the top edge of each piece, so the next row above it covers the fasteners.

When it’s painted the new siding looks as good as the old, it just lasts a lot longer.