Deck Painting & staining across Arlington, Massachusetts.

Outdoor wood here ranges from a new pressure-treated deck behind a single-family house to a century-old porch floor on a two-family. Census estimates count 37.9% of the town's housing units as single-family detached and 23.9% in two-unit buildings, so the outdoor space in question may be a private yard deck or a porch and stair that two households share.

The finish that works depends on three things: the wood species, how much sun and water the surface gets, and what is on it now. Getting those right matters more than the brand of stain.

Wood species and what they want

Pressure-treated pine is widely used for backyard decks. New boards are often too wet to take stain well, so they need time to dry out first. A penetrating semi-transparent or solid stain suits it better than a film-forming paint, which tends to peel on horizontal boards that see standing water and foot traffic.

Cedar weathers to gray if left bare and takes an oil-based or penetrating stain well. Fir porch flooring takes a porch-and-floor enamel well once it is sealed on all sides. Mahogany and other dense hardwoods resist absorbing stain, so they need a product made for hardwoods and a lighter hand. Composite and PVC decking is a different category and normally just needs cleaning.

• Wash or strip the old finish down to sound wood
• Replace split boards and set or replace raised fasteners
• Let wood dry fully before the first coat
• Coat railings and balusters with the same system as the floor

Historic district rules for decks, porches and steps

Inside Arlington's seven local historic districts, the commissions' design guidelines require visible steps, stairs, decks and porches to be built of finish-grade wood such as fir, cedar or mahogany. Pressure-treated lumber is allowed only as concealed framing, and exposed composite, PVC or vinyl isn't allowed. That rule has a direct effect on finishing: a district porch built or repaired under these guidelines will have exposed wood such as fir, cedar or mahogany, and it needs a finish suited to that species.

The guidelines say the commissions don't review paint color, and replacing boards with exact duplicates is handled as a like-kind repair with a Certificate of Non-Applicability. Swapping wood for exposed composite is a different matter, and the district guidelines don't allow it.

Stain or paint?

A solid stain or paint hides more of the wood and lasts longer on vertical surfaces, but on walking surfaces it wears in traffic lanes and can peel. A semi-transparent stain shows the grain and wears away gradually rather than flaking, which makes recoating simpler. Our comparison of painting vs. staining a deck goes into the trade-offs, and the post on deck stain through a New England winter explains what freeze-thaw does to each.

Shaded decks that stay damp dry slowly and grow mildew, so they need a thorough cleaning before any coat. Decks in full sun fade faster and may need recoating on a shorter cycle.

Scheduling around the weather

Stain needs a dry surface and a few dry days, and late-fall dew can keep boards damp well into the day. If the season has closed, the estimate can still be done now and the cleaning and coating scheduled for spring. Neighborhood notes are on our Arlington Center and Jason Heights pages. If the siding and trim are due too, see exterior painting in Arlington.