Deck Painting & staining right here in Sharon, Massachusetts.

Roughly 42% of Sharon's land is permanently protected open space, including the Moose Hill Wildlife Sanctuary, which the town's open space plan puts at more than 2,000 acres, and part of Borderland State Park. The same plan names oaks, white pine, hemlock and red maple among the dominant trees in the town's forests and wetlands. A deck that backs onto woods like these sees more shade, leaf litter and lingering moisture than one in an open yard, and its finish has to be chosen with that in mind.

Four things set the plan: the decking material, how much sun reaches the boards, how damp the ground underneath stays, and what coating is on the wood now.

Shade, needles and tannin stains

Pine needles and oak leaves packed into the gaps between boards hold water against the wood and give mildew a foothold. Wet oak leaves also release tannins that leave dark blotches on light-colored stain. Before any new finish, the deck needs a cleaner suited to the existing coating, a full rinse, gaps cleared with a putty knife, and an oxalic-acid brightener to even the color and neutralize the cleaner.

With about 48 inches of rain a year, as reported in the open space plan, a deck in deep shade may stay damp for days after a storm. Semi-transparent penetrating stains with a mildewcide cope with that better than thick film-forming products, which can trap moisture in the wood and lift.

Damp ground, the lake and the frame

Red maple wetlands and the 250-acre Great Cedar Swamp lie in the southern part of town, and Lake Massapoag, a 353-acre Great Pond, sits just south of the town center. A deck near water or built low over soggy soil dries from beneath very slowly. Before refinishing, probe joists, stair stringers and the ledger board for soft spots, replace rotted boards, and keep skirting open enough for air to move.

Sealing fresh cuts on replacement boards and keeping soil and mulch from piling against the posts both slow the damage that no topcoat can stop.

Match the finish to the wood

Floors and rails can get different treatment. Foot traffic and standing water wear a film off a deck floor in patches, so a stain that erodes evenly is easier to maintain there, while railings and fascia shed water and can carry solid stain or paint much longer. Our paint vs. stain comparison covers the trade-offs.

• Pressure-treated pine: new boards are often too wet to absorb stain. Drip water on them; if it beads up instead of soaking in, wait before staining.
• Cedar: turns silver-gray when left bare and accepts oil-based or semi-transparent stain readily.
• Ipe and other tropical hardwoods: so dense that regular stain stays on the surface and peels. Use a thin hardwood oil or let them weather.
• Composite or PVC: no stain needed; a wash with the maker's recommended cleaner handles mildew.

Painted porches on older homes

The open space plan recounts how, once train and trolley service arrived, middle-class Boston businessmen built summer cottages along Lake Massapoag and elsewhere in town. Porch floors and railings on older houses, and on any home from before 1978, may carry lead in the lower coats; 62.7% of the town's housing units were built before 1980. If testing finds lead, the EPA rule calls for ground covering, no dry power sanding without HEPA dust control, and careful cleanup. Scraping loose spots and repainting with porch-and-floor enamel disturbs much less paint than stripping a porch down to stain it. More on our lead-safe painting page.

Planning the work

Stain goes on dry wood with a rain-free day or two ahead and temperatures above the product's minimum. Short, dewy days late in the year make that hard to get, so an assessment in fall or winter and staining in late spring is a practical sequence. The post on deck stain and New England winters explains freeze-thaw wear. If the house needs paint as well, see exterior painting in Sharon.