How to tell if your deck needs refinishing

Before you give up a weekend to refinish your deck, spend five minutes finding out whether the deck needs anything at all, and whether the job is one you should be doing yourself.

Two Toronto-area deck Pros walked us through how they make that call: Ivan of Supreno Landscaping and the team at Veles Construction.

Start with water

Flick some water across a few boards, especially the sunny ones and the ones you walk on most.

If it beads up, the finish is still doing its job. You can stop here and check again next season. If it soaks in and the wood darkens where it landed, the finish has worn through and the wood is no longer protected. It's time to redo it.

Test a few spots, not one. A deck almost always fails in the walking path and on the stairs long before the railings do, so those are the places to check.

The other signs

Colour is the big one. A deck that has faded to grey or silver isn't just cosmetic. Pigment is what blocks the sun, so once the colour goes, the wood is taking UV damage. Cedar is the clearest example: left unsealed, a cedar deck greys within two or three years, according to Veles Construction.

The other signs are what you would likely expect. A surface that's gone dry, rough, or splintery. A blotchy look where some areas wore faster than others. And a finish that's peeling, cracking, or flaking, which is a different problem, and the one that decides how much work you're in for.

What's already on the deck decides how big the job is

If the deck is bare wood, or has a penetrating stain that's simply worn thin, you clean it and put a fresh coat on. That's the easy path.

If there's a finish that sits on the surface as a film (a solid stain or paint) and it's peeling, you likely have to strip or sand it off before you can recoat. Putting a fresh coat over a failing film just traps the problem, and it peels again. This is why both pros steer homeowners away from solid stains in the first place: once one is on, you're committed to it. As Ivan puts it, a solid stain is "a one-way ticket. The wood always has to be stained like that." Switching to anything lighter later means stripping the old finish off completely, which he calls the most painful part of the job.

So before you commit, you need to know which kind of finish is on there. If you didn't put it on, here's how Veles Construction says you can tell oil from water-based:

• A water-based finish lifts and flakes off the wood in thin sheets as it ages.

• An oil finish soaks in and becomes part of the wood, so it wears away rather than peeling. If the old finish is coming up in flakes, it was water-based. If it's just thinning and fading with nothing to peel, it was oil.

When in doubt, do a small test patch in a hidden corner before you commit to the whole deck.

When it isn't a finish problem at all

Everything above assumes the wood is sound. Sometimes it isn't, and that's the point where you should stop and have a Pro look before you seal anything.

Press on the boards, especially anywhere that stays shaded and damp. Wood that's solid takes a finish. Wood that's rotting won't. Veles Construction describes the test by feel: a healthy board might have a chip or a crack, but rotted wood has a soft, almost goopy texture. A new stain "won't take," they say, "because it's already eaten away." There's nothing sound left for the stain to soak into.

Ivan looks for the same thing, and adds a couple of signs: boards that have twisted, or opened up big holes. Splits and holes can sometimes be filled, but soft or crumbling wood usually can't, because it may be structural, holding up something you walk on. No amount of stain fixes that. If you find it, don't seal over it. Get it looked at.

Sometimes the honest answer is: don't restain it at all

Veles Construction estimates that in about half the decks people ask them to restain, it's actually the wrong call, and the better move is to rebuild. The reason is partly the rot above, and partly how older decks were built: screws driven straight down through the tops of the boards, so water pools at every screw and works its way in. By the time a deck like that shows the damage, restaining it is treating the symptom.

And the labour math is closer than you'd think. Doing a restain properly isn't a quick coat of stain. It's a day of cleaning and pressure washing, removing hardware, protecting the area, then a day or two of careful application, going around every picket and into every corner. A big deck can run four days. Rebuilding a deck whose footings are still good, so you're just reframing the surface, can take about the same time. At that point the difference is mostly the cost of new lumber, and what you get for it is a deck you don't have to think about again, instead of one that's due for the same work in two years.

Before you spend a weekend on it, spend five minutes answering the question that matters: does this deck need refinishing, or doesn't it? Water that beads and colour that's holding means leave it. A finish worn through means do it. Soft, crumbling boards mean stop and get them checked before you do anything.