Deck staining protects the timber from sun and rain and gives it an even colour. On the North Shore that means a deck that stays easy to look after through hot, salty summers and damp winters. A deck is cleaned, left to dry, lightly sanded where the grain has lifted, then stained or oiled in two coats along the length of the boards. Pine decks take stain readily. Dense hardwoods such as kwila and the Australian hardwood jarrah need products made for them. Published New Zealand prices put professional staining at about $20 to $40 or more per square metre plus GST. Below is how to choose a stain, how to prepare the deck, and what happens if it rains.
A small deck usually costs $500 to $900 or more to stain, and a large one $2,000 or more, going by published New Zealand prices. Oiling a small deck is about $400 to $800 or more. All plus GST. Weathered decks that need heavy cleaning or sanding cost more.
Choosing a deck stain or oil
Use a decking stain or decking oil made for horizontal timber, never a fence or wall stain. Decking products are made to handle foot traffic, standing water and strong UV rays. Pigmented stains give more colour and protection from the sun. Clear oils show the natural grain but need recoating more often. Waterborne stains dry fast and clean up with water.
Decking stain
- Pigmented colour, more UV protection
- Recoat about every two to four years
- Evens out patchy or grey timber
- Suits pine and weathered decks
Decking oil
- Soaks in, shows the natural grain
- Recoat about every 12 to 18 months
- A clear or lightly tinted finish
- Suits hardwoods such as kwila
Recoat times are from a New Zealand cost guide. Your deck's sun, shade and salt exposure change them.
Preparing a deck for staining
Clean the deck with a deck cleaner and a stiff brush, rinse it, and let it dry fully, often for two days. Sand only where the grain has lifted, boards are rough or old coating is failing. Punch in raised nails and replace loose or split boards. The stain needs clean, dry, bare-ish timber to soak into, or it peels.
- Clean. Deck cleaner, a stiff brush, then rinse.
- Dry. Usually a day or two of fine weather.
- Fix and sand. Nails, loose boards, rough grain.
- Two coats. Along the full length of each board.
When a deck needs sanding
A deck does not always need sanding. One in reasonable condition usually only needs a thorough clean. Sand when the grain has lifted and feels rough, when old stain is patchy or peeling, or when the boards are grey and weathered. Over-sanding a deck can close up the surface so the stain soaks in less, so painters sand only where it helps.
Pressure washing a timber deck
A timber deck can be pressure washed, with care. A low-pressure wash with a wide fan nozzle and a deck cleaner works well. High pressure held close tears up soft timber like pine and raises the grain, which then needs sanding. Auckland Council's guidance on water blasting says wash water carrying cleaners or old coatings should be kept out of the stormwater drains.
Rain soon after staining
Light rain on a deck stained a few hours earlier can leave spots or a blotchy patch, and heavy rain can wash some stain off. Most spots can be fixed by lightly cleaning and recoating the patch once the deck is dry. To avoid it, painters check the forecast and stain only when there is dry weather ahead, as the label for each product sets out.
Letting a new deck weather first
New timber should usually weather before the first stain. Resene's data sheet for its waterborne decking stain says to let new, dressed or dense timber weather for two to three months first. Weathering opens the surface so the stain soaks in. Kwila can also bleed red tannin in its first months, and weathering lets much of that wash out first.
Popular deck stain colours
Natural timber tones, such as cedar, kwila and light oak shades, are the most common choice for decks on North Shore homes, because they suit gardens and coastal light. Grey and charcoal stains are popular on modern homes. Darker colours hide wear well but get hotter underfoot in summer, which matters on a sunny north-facing deck.
FAQs
How many hours does it take to stain a deck?
A small deck can often be stained in a day once it is clean and dry. The cleaning and drying usually take longer than the staining itself. A large deck with stairs and railings can take two to three days. Weather decides the timing more than anything.
How often should a deck be stained?
A pigmented decking stain usually needs recoating every two to four years. A decking oil usually needs a fresh coat every 12 to 18 months. Decks in full sun or near the sea need it sooner. Recoat when water stops beading on the surface and the colour fades.
How do you protect a deck from planters?
Raise pots on feet or a stand, so water drains and air moves under them. Planters left flat on the boards trap water, stain the timber and stop the stain from wearing evenly. Move them now and then, and lift them off the deck when it is cleaned and stained.
Can you stain a deck that was painted?
Not easily. Stain needs bare timber to soak into, so any paint has to come off first, usually by stripping and sanding. On a painted deck in good condition, repainting with a decking paint is often simpler. Your painter will check the coating and say which is more sensible.