Deck Restoration in the GTA: Cleaning, Sanding & Sealing Explained

A wood deck in the GTA takes a serious beating over the course of a year. Harsh winters, spring moisture, summer UV exposure, and fall debris all take their toll. By the time most homeowners look at their deck in April or May, it's greyed out, weathered, and showing its age in a way that makes the whole backyard feel tired.

The good news is that most weathered decks look dramatically better after a proper restoration — often like a completely different deck. The process involves three steps: cleaning, sanding, and sealing. Here's what each step actually involves and why all three matter.

Step 1: Cleaning

Cleaning is the foundation of any deck restoration. It removes the surface grime, mould, mildew, algae, and grey weathering that make the deck look tired — and more importantly, it opens the wood grain so that stain or sealer can properly penetrate.

Pressure washing is the primary tool, but technique matters. Too much pressure on soft wood species like cedar and pine causes surface fibres to fuzz up and raise, which creates problems at the sanding and sealing stages. The right approach uses moderate pressure with the correct nozzle, working with the grain, and keeping a consistent distance to avoid striping.

For decks with significant mould or mildew growth, a pre-treatment with a biodegradable wood cleaner before pressure washing makes a meaningful difference. The cleaner does chemical work on organic growth that pressure alone can't achieve, reducing how much mechanical work the pressure washer needs to do.

Step 2: Sanding

Sanding is the step that most people skip — and the one that makes the biggest difference in the final result.

Pressure washing, even done correctly, raises the wood grain slightly. Sanding after the deck dries knocks that raised grain back down to a smooth surface, which is critical for two reasons: it significantly improves how the stain looks when applied, and it removes any remaining grey surface fibres that cleaning didn't lift.

For a deck that's being restored after several years of neglect, sanding also removes any remaining old stain or sealer that didn't wash off. Applying new stain over old, partially-removed stain results in an uneven, blotchy finish — sanding creates a clean, consistent surface.

The sanding doesn't need to be aggressive — a light pass with 60–80 grit, followed by 100 grit on areas that need it, is typically sufficient for most residential decks. The goal is surface consistency, not removing significant material.

Step 3: Sealing or Staining

Once the deck is clean, dry, and sanded, it's ready for a protective finish. There are three main options:

Clear sealer

Provides UV and moisture protection while allowing the natural wood colour and grain to show. Good for newer decks in good condition where you want to preserve the natural look. Typically needs reapplication every 1–2 years as it doesn't penetrate as deeply as stain.

Semi-transparent stain

The most popular choice for residential decks in the GTA. Penetrates the wood grain, enhances the natural colour and character, and provides excellent UV and moisture protection. A quality semi-transparent stain on a properly prepped deck lasts 2–4 years before reapplication.

Solid stain

Provides maximum colour coverage — essentially paints over the wood grain. Best for older decks with significant weathering or discolouration that you want to cover completely. Very durable but requires more maintenance when it does wear, as it tends to peel rather than fade.

How Long Does a Deck Restoration Take?

A typical residential deck restoration in the GTA — cleaning, drying time, sanding, and one coat of stain — takes 1–2 days on site, with an additional 24–48 hour drying period before the deck can be fully used. Weather dependent, the full process from cleaning to final coat is typically completed within 3–5 days.

How Much Does Deck Restoration Cost in the GTA?

Cost depends on deck size, condition, and the scope of work. A pressure wash only is priced differently from a full wash, sand, and seal package. As a general guide:

• Wash only — smaller decks start in the $150–$250 range, larger decks up to $400+
• Wash + sand + seal/stain — most residential decks fall in the $500–$1,200 range depending on size and material costs
• Large decks or complex layouts — multi-level decks, pergolas, and large entertaining spaces can run $1,500–$3,000+

When Is a Deck Beyond Restoration?

Not every deck can be restored. Signs that restoration won't be enough:

• Soft, spongy boards — probe with a screwdriver; if it penetrates easily, the wood has rotted through and boards need replacing
• Structural issues — loose or corroded fasteners, failing posts, or a ledger board that's pulling away from the house are structural problems, not cosmetic ones
• Deep cracking and checking — surface checks are normal, but deep cracks that run through the board allow water ingress and accelerate decay
• Persistent black staining — if deep black mould staining doesn't respond to cleaning and brightening, the wood fibres themselves are compromised

A good restoration contractor will tell you honestly whether the deck is worth restoring or whether board replacement makes more sense. If you're getting quotes and one contractor is telling you the deck needs full replacement while others say it's restorable, get a third opinion — the answers should be broadly consistent.