Building An Addition: A Homeowner's Guide

How To Clean, Prepare, And Paint Your Home's Fiber Cement Siding

by Toni Richards

Siding installed on your home can give your home's exterior a uniform and attractive appearance while making its up-keep low or maintenance-free, depending on the type of siding you have installed. Fiber cement siding is an increasingly popular type of siding for homes, as it has the look of wood, but is resistant to rot and insects and can be relatively inexpensive compared to other types of siding. Fiber cement siding is made of Portland cement, sand, wood pulp, and other binding materials, which makes it easy to paint and allows it to hold the paint well to prevent peeling and flaking. Here are some tips to help you clean, prepare, and paint your home's new or existing fiber cement siding.


If your home already has fiber cement siding installed that you want to repaint a different color, you first need to clean its surface. Because of the materials used in producing fiber cement siding, it can easily allow mold and mildew growth on its surface.

Create a mold-cleaning solution of three-fourths cup of bleach to one gallon of warm water and apply this to the mold with a cloth or a sponge. Be sure to wear rubber gloves so the bleach doesn't irritate your hands. You can also use a household cleaner that contains bleach to remove and kill any remaining mold spores. Rinse the area with clean water to remove all the cleaning agent or bleach residue, as this can damage the surface of your siding if it is allowed to remain. 

Next, it is important to clean any dirt and other debris, such as bird and insect droppings, from the surface of your siding. The best tool to clean your siding is a power washer. You can rent a power washer from most equipment rental stores. Be sure you use a low pressure black-colored or 40-degree white-colored universal power washer nozzle tip to avoid damaging or causing gouging to occur into the fiber cement siding. Wash the siding from the top down so you can efficiently clean the surface.

If you don't have access to a power washer, you can clean the surface of your siding with a soft-bristled scrub brush and water. Be sure to rinse the surface clean with your garden hose when you have finished scrubbing to remove any debris and dirt. Allow the siding to dry for several days so all traces of moisture have evaporated from the surface. 

Prepare and Paint 

Your home's siding should already have been primed at the factory before it was shipped to your home. If you are not sure about it being primed, contact the siding manufacturer. If your siding is unprimed, prime it with a high-quality exterior acrylic masonry primer.

Then, take care that you paint the pre-primed siding within six months, as the primer can begin to break down. If your siding has previously been painted, make sure to sand off any flaking and peeling paint before applying a new coating.

It is important to seal any cracks, transition seams, openings, and siding edges where the siding meets your home's trim using an acrylic caulk. This protects the siding material from absorbing moisture through any exposed openings, which would cause the material to deteriorate.

When you are ready to paint the siding, be sure to select an all-weather exterior acrylic paint to protect the siding and prevent mold growth. Apply the paint in two coats, allowing the first to dry completely before you apply the second. You can use a brush to apply the paint, following the grain pattern on your siding.

Use these tips to help you prepare and paint your fiber cement siding. For more information on fiber cement siding, contact a company like Lifetime Exteriors.