How to Paint Outdoor Railings

Q: I have cedar front-porch railings that I built years ago. The paint is gone in many areas or is peeling away. What is the best way to prep weathered cedar and repaint it white?
—BRAD STUBBS, LEE’S SUMMIT, MO

This Old House painter Mauro Henrique says: Cedar resists rot and insect damage, so it will be worth your while to get your railing back into shape. Paint is a good choice for your railings; it will withstand sun and weather exposure better than other exterior coatings.

Watch as Mauro paints an outdoor railing to match the original railing around a homeowner’s deck.

Steps for Painting Exterior Railings

1. Use painter’s tape to protect the deck and the older railing.
2. Put a dropcloth down to catch any debris, primer, or paint.
3. Use 180-grit sandpaper to sand down any imperfections in the wood. Mauro used a sanding block for the balusters and a random orbital sander for the posts and railings to get the job done quicker on the larger areas.
   a. Wear a mask and gloves to protect yourself from splinters.
4. Vacuum all the debris.
5. Start priming. Use a mini roller for the larger areas and a paintbrush for the areas that are harder to get to.
6. Focus on the bottom wood, that’s where most of the water will end up.
7. Let the primer dry before painting, wait about an hour.
8. Fill in any nail holes with exterior-grade wood filler.
9. Paint.
10. Let the first coat dry and add the second coat.

Pro Tip: Painting contractor John Dee, a This Old House contributor, stresses that priming is “the most important part of the job.” As he explains: “I only use oil-based primers because they adhere to the wood so tenaciously and block the brown stains that bleed through cedar and redwood, something the latex primers can’t do.”

Pro Tip: While Mauro usually relies on his brush skills to keep paint off adjoining surfaces, he always masks off around post bases with painter’s tape to create a clean line.

Don’t forget to prime the bottom of the bottom rail—as painting contractor Mara reminded on Ask This Old House, the bottom unprimed or unfinished surface is going to absorb all the moisture, which won’t do any good for the paint job or the wood itself.

Resources

Mauro wanted to match the paint color of the existing deck, which he did by bringing a small sample of the existing paint to a local paint store. Most paint stores and home centers have machines that can scan a sample and generate a close color match to the paint.

The paint Mauro used for the railings was Behr Premium Plus Exterior Semi-Gloss paint and primer, though he also used a separate, oil-based primer for the base coat.

Pro Tip: As one This Old House painting expert explains: “Sometimes there’s primer and paint in one can. Well, this is the way I like to do it. I like to use the primer first, only primer, and then I’ll top coat it with that.” Using a dedicated primer as a base coat—rather than relying on a combined paint-and-primer product—ensures better coverage and long-term durability, especially on exterior surfaces exposed to the elements.

Mauro notes that his oil-based primer dries in about one hour, making it a very fast-dry option that lets you move on to painting quickly. For cleanup, he explains the difference between paint types: “If you’re working with a water-based paint, warm water, a little soap. That takes care of that.” For oil-based products like the primer, paint thinner is the right solvent for cleaning brushes.

Shopping list

• Painter’s tape (exterior grade)
• Dropcloth
• 180-grit sandpaper
• Gloves
• N-95 mask
• Vacuum
• Oil-based primer
• Exterior wood filler

Tools