Repainting James Hardie Siding
Fibre cement holds paint well and doesn’t need repainting often. When the time comes, preparation decides how long the new coat lasts.
When does it need repainting?
There’s no fixed schedule. A factory ColorPlus finish is designed to last a long time and carries a 15-year limited finish warranty. Site-applied paint over primed boards depends on the paint, the painter and the exposure. South and west walls age faster than north ones. Signs that it’s time include general fading, a chalky residue that comes off on your hand, and peeling or flaking.
Plenty of people repaint for a different reason: they want a new colour. That’s perfectly reasonable, and it’s one of the advantages of fibre cement over claddings that can’t be painted successfully.
Find out what’s on the wall now
Knowing whether the existing finish is ColorPlus or site-applied paint helps the painter choose products. If you’re not sure, your original quote or the installer may be able to tell you. If part of the finish warranty is still running, check its terms before painting over it; new paint is covered by the paint manufacturer, not by James Hardie.
Preparation
- Wash. Dirt, chalk and mildew have to come off. Use a garden hose, a soft brush and a mild cleaner. Avoid high-pressure washing, which can damage the surface.
- Let it dry. Completely. Painting over damp fibre cement traps moisture.
- Repair. Fill chips, replace broken boards and renew failed caulking. See repairs.
- Deal with loose paint. Scrape and feather any flaking areas and spot-prime bare patches with a primer suited to fibre cement.
- Mask. Windows, fixtures, stone and anything else that isn’t being painted.
Paint
Use a high-quality 100% acrylic exterior paint. Avoid oil-based paints and stains on fibre cement. Two finish coats give the best colour and durability. A low-sheen finish hides surface irregularities better than gloss.
Weather
Paint needs mild, dry conditions to cure. In Calgary that means late spring to early autumn, on days without rain, strong wind or a big overnight temperature drop. Follow the temperature limits on the paint can, and avoid painting a wall in direct hot sun, which dries the paint too fast.
Going darker or lighter
Fibre cement is stable enough to take a dark colour. Bear in mind that dark colours show dust, water marks and chips more readily. Going from dark to light usually needs extra coats for coverage. More in dark siding colours.
Do it yourself or hire?
A single-storey house is within reach of a careful homeowner with good ladders and patience. Two storeys, complex trim or a sprayed finish are jobs for a professional. Either way, the cleaning and repair steps are what you’re really paying for. Paint over a dirty, damaged wall fails early.
Trim, soffit and fascia
Paint them at the same time. Fresh siding next to tired trim looks unfinished, and the access is already set up. It’s also the moment to change the trim colour if you’ve wanted to. Ideas: colour combinations.