There are a few ways to fix holes in fiber cement siding. You can use a caulk gun to fill the hole with silicone caulk, which is a common method and usually works well. Another option is to use an exterior spackling compound to fill the hole. This option might be better if you have a lot of small holes to fix, as the spackling compound is designed for patching up small cracks and blemishes on surfaces like this. Finally, you could also use a piece of backer rod (a foam tube) and some exterior adhesive to plug up the hole from the inside. Whichever method you choose, be sure to let the adhesive or sealant cure completely before painting over it.

There are a couple of ways to repair holes in fiber cement siding. One way is to use an epoxy putty to fill the hole and then sand it down until it's smooth. Another way is to use a caulk gun to apply a sealant over the hole.If you decide to use an epoxy putty, make sure that you get one that is made for fiber cement siding. There are different types of epoxy putties, and some are better suited for repairing fiber cement than others. When you're shopping for epoxy putty, look for one that says "fiberglass" or "fiber cement" on the label.