Deck Painting & staining in Boxborough, MA.

A 2006 state heritage report describes old farms being divided into house lots after I-495 arrived in the mid-1960s, with growth continuing through the end of the century. Today 59.3% of the town's housing units are single-family detached homes, and on a detached house the deck is the owner's alone to maintain.

Lots that border woods or sit under tall trees create a specific set of deck problems. Boards in shade stay wet for days after rain, pine needles and leaves pile up in the gaps between boards and hold moisture against the wood, and mildew turns the surface gray-green. A deck that gets full afternoon sun has the opposite trouble: the stain fades and the top fibers weather and check. A single deck can have both conditions, one at each end.

Penetrating stain or solid color

Transparent and semi-transparent stains soak into the wood and wear away gradually. When they fade, the next round is a cleaning and another coat, with no scraping. They show the grain, which suits cedar and good-quality pressure-treated lumber. Solid stains and deck paints sit on the surface as a film. They hide mismatched or weathered boards and block more sunlight, but when a film fails on a walking surface it peels, and peeling film has to be scraped and sanded before recoating.

On a shaded deck that stays damp, a film coating can trap moisture and peel faster, so a penetrating product is often the more forgiving choice there. The deck paint vs. stain comparison goes through the trade-offs in more depth.

• Pressure-treated pine: new lumber needs time to dry before its first coat; sprinkle water and see if it soaks in
• Cedar: takes oil-based and semi-transparent stains well; watch for tannin bleed under light solid colors
• Composite or PVC decking: cleaning, not staining, unless the manufacturer approves a coating
• Railings and balusters: often get a solid stain even when the floor gets a semi-transparent one

Prep that decides how long it lasts

The order matters: clear debris from between the boards, wash with a deck cleaner, rinse, apply a brightener to neutralize the cleaner and open the grain, then let the wood dry for at least a couple of dry days. Raised fibers are sanded, popped nails are reset or replaced with screws, and soft boards are replaced. The places to check for rot are the stair stringers, the ends of boards over the joists, and the ledger where the deck meets the house.

A deck on a house from the 1970s, a decade that accounts for 24.1% of the town's housing, may carry old paint if it is original. If the paint predates 1978, scraping more than 20 square feet of it outside triggers EPA lead-safe requirements; the lead-safe painting page describes them.

Condo and townhouse decks

More than a third of local units (34.3%) are in buildings with five or more units, and 115 more are single-family attached homes. On those, a deck or balcony is often a limited common element, which means the association may control the color, the product or who is allowed to do the work. Before staining a condo deck, check the master deed and rules, and expect the association or property manager to want a certificate of insurance from the contractor.

When to stain

Stain needs dry wood, temperatures in the product's range, and no rain for a day or so after application. Late spring through early fall is the practical window in this part of Massachusetts, and working in the morning or late afternoon keeps the stain from drying too fast in direct sun. If the house trim is also being painted, doing the house first and the deck last protects the new finish on the boards. Read how deck stain holds up in a New England winter before choosing a product.