Sealing a deck after blasting: timing and product

The strip is the visible half. The finish is the half that decides how long it lasts.

How long you have

Days, not weeks. Freshly stripped wood is at its most absorbent and its most vulnerable, and in our sun it will start greying again quickly. Have the product bought before we start.

Let it dry first

Wet blasting leaves the boards damp. Most finishes need the moisture content down before they will penetrate and cure properly — usually a couple of dry days, longer if the weather turns. Applying over damp wood is the most common cause of an early failure.

Choosing the product

• Penetrating oils weather back gradually and recoat with a wash. Best choice for most decks.
• Semi-transparent stains give more colour and more UV protection while still failing gracefully.
• Solid stains and deck paints look great for two years and then peel, which puts you back to stripping.

Pigment is what stops UV. A clear finish on a deck in this sun is a one-season decision.

Two thin coats

Freshly blasted wood will drink the first coat. Two thin coats penetrate and last far better than one heavy one, which tends to sit on the surface and skin over.

The dry air around Medicine Hat is an advantage — boards come back to coating moisture faster here than almost anywhere in Canada — but a shaded deck in River Flats or Riverside still needs longer than an open one in Southridge.