How to Strip and Re-Stain a Timber Deck
Every Adelaide Hills tradie I respect has the same opinion on belt-sanding a deck: don’t. Sanding a hardwood deck takes 2 mm off the board surface, exposes the soft summerwood between the dense growth rings, and gives you about two or three recoat cycles before the boards are too thin to be safe. A 19 mm-thick merbau board started at 19 mm. After three sand-and-recoats it’s down to 13 mm and the screw heads are cratered. The proper trade method is chemical stripping followed by a stiff broom and a hose. Done right, it gets the old finish off, lifts the embedded grime, and leaves the timber surface intact at the original thickness. My apprentice Jacob argued with me about this his first year on the tools because his uncle had told him “you can’t strip a deck properly without a sander”. Two days later he was scraping fluffed grain off a customer’s south-facing deck with a putty knife trying to undo what the sander had done. Twenty years on the tools and I still see the same mistake every season. Here’s the right way.
What you’ll need
- Cabot’s Deck Clean or Wattyl Solvastrip — 4L covers about 25 m² ($50–$70)
- A stiff-bristle deck broom (Sabco Deck Brush or Gala, $25)
- A garden hose with a fan-spray gun — NOT a high-pressure washer (Step 4)
- Plastic drop sheets to protect plants below the deck and adjacent paving
- Long rubber gloves, eye protection, old clothes, enclosed shoes
- Cabot’s Aussie Clear, Cabot’s Deck & Exterior Stain, or Sikkens Cetol Deck — colour matched to your timber ($95 for 4L)
- A quality lambswool applicator on a pole ($35)
- A 75 mm brush for between-board edges and cut-ins
- A dry weather window of 3 days minimum (BoM, not the phone app)
- A pin-style timber moisture meter ($50 at Bunnings) — Trotec or General Tools
Step 1: Clear the deck and check the weather
Move every chair, pot plant and BBQ off the deck. Sweep the leaves out of the gaps between boards with a paint scraper or a 5-in-1 tool. Check the BoM forecast — you want at least three dry days. Strip on day one, recoat on day three. Rain during the strip is fine; rain on wet stain is a disaster that you can’t paint over. Down here in the Hills the spring forecast is often more reliable than the iPhone weather app, which struggles with the elevation change between Adelaide and Stirling.
Step 2: Wet the deck, then apply the stripper
Hose the deck down to wet the boards — stripper works better on damp timber, not bone dry. Pour Cabot’s Deck Clean into a plastic watering can, dilute according to the label (usually 1:3 or 1:4 with water), and pour evenly across about 5 m² at a time. The product foams slightly as it reacts with the old finish. Don’t try to spread it with a brush at first — the watering can gives even coverage, the brush comes next.
Step 3: Scrub with the deck broom in the direction of the grain
Working in 5 m² sections, scrub firmly along the length of the boards — never across. The broom bristles need to enter the timber grooves to lift residue. Old grey finish lifts as a brown-grey slurry. Keep moving — don’t let the stripper dry on the boards or it leaves streaks that show in the final stain. The number of leak callbacks I’ve done because someone scrubbed across the grain and left the timber fluffed up to drink water is genuinely depressing.
Step 4: Rinse with the hose, NOT the pressure washer
Standard advice on YouTube: pressure-wash the deck. This is wrong for Aussie hardwoods. A 1500 PSI pressure washer fluffs the soft summerwood between growth rings, leaving a furry surface that holds water and rots prematurely. A garden hose with a fan-spray gun (Hozelock or Pope, $30 at Bunnings) lifts the slurry without damaging the surface. Take your time — work along the boards, fan-rinsing the foam off until the water runs clear. For the right surfaces to actually use a pressure washer on, see how to pressure-wash a driveway safely.
Step 5: Repeat on stubborn sections
Areas with thick old film (under chair legs, around the BBQ stand, anywhere protected from sun and rain) often need a second coat of stripper and a second scrub. Don’t try to rush this with extra-strong stripper — same product, second pass, more elbow grease. The deck should end up uniformly bare timber, slightly damp, with no patches of old grey film visible. Take a torch out at night and look for dull patches; sun-bare timber reflects light, sealed timber doesn’t.
Step 6: Let the deck dry for at least 48 hours
Hardwood deck boards need to drop to under 18% moisture content before staining or the stain won’t penetrate. In Adelaide summer that’s 24–48 hours. In a Hills winter or rainy stretch you might need 4–5 dry days. A pin-style timber moisture meter from Bunnings tells you precisely when you’re ready — push the pins in across the boards, look for under 18%. Without one: timber should look uniformly pale, no dark damp patches, and the surface should feel dry to a back-of-the-hand check. Hill’s water down here is hard, so any mineral residue from the rinse can also slow penetration if you haven’t dried thoroughly.
Step 7: Sand only the rough spots — by hand
Where the broom raised splinters or where there’s existing damage, hit just those sections with 120-grit sandpaper on a sanding block — by hand, not a belt sander. Lightly. Wipe dust off with a damp cloth and re-check moisture before staining. If you want help picking the right sander for unrelated jobs (not this one), see how to choose and use an orbital sander — but on a deck, hand-block only.
Step 8: Apply the first coat of oil stain — thin and along the grain
Stir Cabot’s Deck Stain thoroughly — pigment settles fast and you’ll get colour banding if you don’t. Pour into a paint tray. Load the lambswool applicator, beat off excess against the tray ridge, and lay the stain along the grain in lengths of 1–2 boards at a time. The first coat penetrates into the timber, not onto it. Use a 75 mm brush to cut along joists or rebates and push stain into the gaps between boards. Wipe any pooling stain off after 10 minutes with a clean rag — pooled stain dries shiny and tacky, looks terrible. Avoid direct hot sun while staining; aim for overcast, or stain in early morning or late afternoon. Air temp between 12°C and 28°C.
Step 9: Wait 24 hours, then second coat
Cabot’s needs 24 hours between coats in dry weather. Don’t try to do both coats in a day — the second won’t penetrate, sits on top sticky for weeks, then eventually peels. Same technique on the second coat: thin, along the grain, wipe pooling. While the deck is stripped bare between coats, walk every board and check fixings. A board that flexes more than 5 mm under your foot has either failed fixings or rot. Tap suspect boards with a hammer handle — solid timber rings clearly, rotten timber thuds. Replace any rotten boards before staining. Match the species (merbau for merbau, spotted gum for spotted gum) and use 304 stainless decking screws (DeckMate or Buildex) — galvanised screws bleed rust marks down hardwood within a year due to tannin reaction.
Step 10: Cure 72 hours and the merbau-specific tannin rinse
The stain is touch-dry in 6 hours but needs 72 hours before you put a heavy planter or chair leg on it. Walk on it barefoot after 24 hours if you must, but don’t drag anything. Special note on merbau: it’s the worst tannin-bleeder of all Aussie deck timbers. After stripping, hose the deck thoroughly to flush residual surface tannin — you’ll see brown water running off. Repeat the rinse the next day too. Merbau tannin runs into nearby tiles, concrete and pavers and stains them rust-orange that you cannot scrub out. Lay plastic sheeting under the deck overhang and on adjacent paved areas during the strip and rinse phase, especially on a sloped block.
When to call a tradie
Strip-and-stain is a homeowner job for an able-bodied person with two free days. Call a tradie when you find: rot at joist contact points (boards that flex or thud), surface checking deeper than 2 mm along the grain, multiple cupped or warped boards, or any movement in the substructure (a deck that sways under foot). Replacing single boards is a 30-minute hand-tool job per board; replacing the whole deck surface is $80–$150/m² supplied and laid in 2026 prices. Also call a tradie if there’s water staining on a slab below the deck — the membrane between deck and slab may have failed and that’s AS 3740 territory. Anything that breaks the waterproof membrane on a real wet area is licensed work under AS 3740 and not a homeowner job.
Common screw-ups
- Belt-sanding the deck — knocks years off board life, exposes summerwood, leaves cratered screw heads.
- Pressure-washing instead of scrub-and-rinse — fluffed grain, premature rot.
- Staining on damp wood — surface tackiness for weeks, finish peels in a season.
- Skipping the merbau tannin rinse — rust-coloured stains on every adjacent paver, permanent.
- Mixing oil brands between coats — different carriers react, blotchy absorption, expensive redo.
Cost & time
Stripper $50–$70, stain $95, applicator and brushes $50, sundries $20 — about $220 for a 25 m² deck. Time: two days, mostly waiting time. Compare that against $80–$150/m² for full replacement and you can see the maths. A maintained 25 m² hardwood deck is a $300/year hobby. A neglected one is a $4,000 replacement every 12 years.
The deck is a wear surface, not a piece of furniture. Treat it like one: strip it gently, oil it deeply, recoat it often. The boards last 30 years if you respect the timber, 10 years if you sand them every cycle. Cabot’s, Sikkens, Wattyl Forestwood — pick one and stay with it. Mixing brands between coats is how you get blotchy finishes that no amount of effort can fix afterwards. The decks I built in the Hills in 2008 and recoated faithfully every 3 years are still in beautiful nick. The decks where the owner sanded and recoated every cycle have all needed board replacement by year 12. Do it once, do it properly, and the deck will outlast the house renovation cycle.
