Deck Stain vs Seal: Which to Use
Quick answer: stain adds color plus protection; a sealant is a clear barrier that blocks water and UV. For a new deck, stain it; for already-colored wood, a sealant alone works. One gallon covers about 150–300 sq ft.
- Stain vs sealant
- How much you need
- New deck timing
- Coverage chart
- Worked example
- Common mistakes
Stain vs sealant
Deck stain adds color and some protection, in transparent, semi-transparent, or solid formulas. A sealant is a clear topcoat that blocks water and UV without changing the wood color. In practice most "deck stains" include a water repellent, so one product often does both. Choose by whether you want color or want to keep the natural wood.
How much you need
One gallon covers about 150–300 sq ft of deck surface, depending on the product and the wood's absorbency. New or rough wood soaks more, so coverage per gallon drops. Count the top surface, stair treads, railings, and any visible framing you plan to coat, then divide by the product's coverage.
New deck timing
Pressure-treated wood needs to dry before staining — wait about 4–6 weeks after installation. A fresh deck should weather briefly so the grain opens up and takes the stain. Staining too early traps moisture and the finish peels.
Coverage chart
| Deck size | Sq ft (top) | Gallons at ~200 sq ft/gal |
|---|---|---|
| 10×10 | 100 | ~1 |
| 12×16 | 192 | ~1–1.5 |
| 14×20 | 280 | ~1.5–2 |
| 16×24 | 384 | ~2–2.5 |
Add stairs, railings, and edges — they raise the total and the gallon count.
Worked example
A 12×16 deck (192 sq ft top) plus stairs and railings (~50 sq ft):
- Total ≈ 242 sq ft
- At ~200 sq ft/gal → 1.5–2 gallons
- Order 2 gallons for two coats with margin
The deck calculator handles the lumber count; use coverage numbers above for the finish.
Common mistakes
- Staining pressure-treated wood too early. It traps moisture.
- Counting top surface only. Stairs and rails add up.
- No maintenance schedule. Restain every 2–3 years.
- Skipping prep. Clean and sand before you coat.
FAQ
Stain adds color and some protection to a deck; a sealant creates a clear protective barrier that blocks water and UV. Stains come in transparent, semi-transparent, and solid; sealants are clear topcoats.
One gallon of deck stain covers about 150–300 sq ft of deck surface, depending on the product and wood. Calculate your deck's surface area (top, sides, and stairs) and divide by the coverage per gallon.
Stain a new deck after it's weathered a few weeks. For pressure-treated wood, wait 4–6 weeks to dry before staining. A sealant alone works on wood that already has its natural color.
Restain every 2–3 years, or when water stops beading on the surface. A good rule: if water soaks in instead of beading, it's time to reapply.