Deck stain vs paint

Penetration vs film decides everything else

Every row in the table above follows from one property. A penetrating finish goes into the wood and leaves nothing on the surface to let go. A film — paint, solid stain, resurfacer — sits on top, and the USDA's Wood Handbook is blunt about what that means on a deck: films blister and peel when there is persistent moisture in the wood underneath, which is "one reason it is so difficult to get a film-forming finish to perform on horizontal surfaces, such as decks."

The tiers within stain — clear through semi-solid — and how to prep for them are in the deck stain guide. This page is the decision one level up: whether to be in the stain family at all. If the boards are composite or PVC the question mostly disappears — see decking materials compared.

What the Forest Products Laboratory found

The handbook's Table 16–2 compiles researchers' observations of how long each finish lasts on each surface, for an average US location. Read the decking rows against the siding rows and the answer to "stain or paint" changes with the direction the board faces.

Years. The paint figures assume an ideal three-coat system (one primer, two top coats); the handbook says a two-coat system cuts them to about half. Your climate and exposure move every figure.

Floor and railing want different finishes

The deck floor takes standing water, sun on its flat face and every footstep. The railing and the fascia shed water and see no traffic — they behave like siding, which is where paint and solid stain earn their long figures. A deck that is stained on the floor and solid-coloured on the rails is not a compromise; it is each surface getting what suits it. The deck stain calculator already splits the floor from the railing, so you can size each finish separately.

One catch on the rails: the handbook warns that film finishes on fences and railings trap moisture when the end grain is not sealed during construction, and pictures a painted railing failing eight years in. Seal cut ends before any film goes on. Fences follow the same rule — size a fence job with the fence stain calculator.

Switching later is a one-way street

Going from stain to a solid colour is easy — Cabot sells its solid acrylic as covering "old stain of all kinds and mismatched boards". Going back is not. Ready Seal's data sheet says every pre-existing product still present must be completely removed before its stain will work, and that acrylic coatings "may require a paint stripper". Thompson's warns that leaving loose or peeling stain under a new coat "will result in continued flaking and peeling."

Resurfacers, heat and slip

Resurfacers are the thick end of the film family. Cabot's DeckCorrect lists 75 sq ft per gallon in two coats, fills cracks up to ¼ inch and is aimed at weathered decks — a way to buy years from boards you would otherwise replace. It is still a film on a horizontal surface, so everything above about films applies to it. Whether the boards are worth saving at all is the question in how long a deck lasts. Compare the cost against new boards in composite vs wood.

Heat. The handbook notes that darker finishes absorb more sun, and the heating causes more warping and checking than light colours do. Cabot markets a solid stain that it says reduces surface temperature against other solid stains — colour and sun still decide the result.

Slip. Ready Seal's own sheet warns that bare or coated wood can be slippery when wet; resurfacers are sold with a textured, skid-resistant face. Whatever you choose, stairs are where it matters — the guard and stair rules cover the rest of making them safe.