How many square feet does a gallon of deck stain cover on rough-sawn cedar in New Brunswick?

On rough-sawn cedar, expect a gallon of deck stain to cover 150–250 square feet — roughly half the 300–400 sq ft coverage rate printed on the label.

Manufacturer coverage estimates are calculated on smooth, non-porous surfaces. Rough-sawn cedar is an entirely different story. The texture dramatically increases the actual surface area the stain has to penetrate, and cedar itself is a naturally thirsty, resinous wood that drinks up stain quickly — especially on the first coat.

The rougher the texture, the lower your real-world coverage. A lightly weathered rough-sawn board might get you toward the 250 sq ft end of that range. A heavily weathered, grey, dried-out cedar deck that hasn't been stained in several years will pull stain in aggressively and you may land closer to 100–150 sq ft per gallon on the first coat. New, freshly milled rough cedar falls somewhere in between — it's porous but hasn't dried out to the point of being thirsty.

New Brunswick's climate makes this even more relevant. After a long NB winter with 100+ freeze-thaw cycles, UV exposure from the summer sun, and the humidity swings from our Maritime climate, cedar deck boards open up and become increasingly porous year over year. A deck that was stained three years ago and has been through three NB winters will absorb significantly more product than it did the first time around.

Practical Tips for Calculating How Much to Buy

Measure your deck's square footage (length × width, minus any built-in planters or fixed furniture footprints), then divide by 200 sq ft per gallon as your planning number for rough-sawn cedar. That gives you a conservative estimate that accounts for the texture and absorption without leaving you short mid-project.

For a first coat on a weathered or never-stained rough cedar deck, budget for 150 sq ft per gallon. The second coat — applied after the first has fully absorbed and dried — will go further, often 200–250 sq ft per gallon, because the first coat has partially sealed the wood.

Semi-transparent stains penetrate more deeply and cover less area than solid-body stains on rough cedar. If you're using a semi-transparent product like Cabot Australian Timber Oil or TWP (Total Wood Preservative), lean toward the lower end of the coverage range. Solid-body stains sit more on the surface and stretch a bit further, but they're also more prone to peeling on rough cedar if the surface isn't clean and dry.

Timing matters in NB. Apply deck stain when temperatures are between 10°C and 30°C, humidity is below 70%, and no rain is forecast for at least 48 hours. The ideal NB window is late May through early September — avoid applying in direct hot afternoon sun, which causes the stain to dry too fast and prevents proper penetration into the wood.

When to Hire a Pro

A rough-sawn cedar deck is a manageable DIY project if it's a single level and you're comfortable with a pump sprayer or brush. That said, proper prep — cleaning, brightening with a wood cleaner, and letting the wood dry to below 15% moisture content — is where most DIY deck staining goes wrong in NB. If your deck is large (400+ sq ft), multi-level, or badly weathered and greyed out, a professional will have the equipment and product knowledge to get the prep right and the stain applied evenly. Need help finding someone? New Brunswick Painting can match you with a local professional for a free estimate.