FirstCheck
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🍁 Built for Canadian homes — written to Canadian codes and provincial rules. Not intended for use outside Canada.
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A deck board feels soft or spongy underfoot

One soft board is often a simple swap — but because soft wood means rot, it's worth a quick check that the framing underneath is still sound.

tuneWhat are you noticing?
Select anything that matches and the checklist below reorders to fit. Not sure? Skip it.
emergency_home

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Start here

In Canadian homes, start by finding out how far the softness goes. If just one board feels spongy and the framing under it is firm, that board has surface rot — probe it with a screwdriver, then replace the single plank. Check the boards on either side while you're there.

Ranked from real-world failure data. The order updates as you select what you’re noticing above.

Likely causes, in the order to check them

Showing the typical order
Beginner-friendly Doable, with care Safety-critical Call a pro

visibilityHow to check

warning Check the framing, not just the boardA soft board can be hiding rotten framing. Before you spend time replacing a plank, probe the joist beneath it and the area around it — if the structure is soft, this stops being a DIY board swap and becomes a contractor job for your safety.
  1. Press a screwdriver or awl firmly into the soft spot. Sound wood resists; rot lets it sink in easily or crumble.
  2. Probe the boards on either side and, if you can reach underneath, the joist below — you want to know whether the rot is just the one board or the framing too.
  3. If only the surface board is soft and the joist under it is firm, it's a single-board replacement. If the joist is soft, stop and treat it as structural.
buildscrewdriver schedule10 min

handymanHow to fix it

Once you've confirmed the joist below is sound, unscrew and remove the rotted board, cut a matching pressure-treated (or composite) replacement to length, and fasten it down with corrosion-resistant deck screws, leaving a small drainage gap.

  1. Confirm the joist under the board is firm (probe it). If it's soft, stop — this is structural.
  2. Unscrew or pry up the rotted board and remove any old fasteners left in the joist.
  3. Cut a matching pressure-treated or composite board to length and set it with the same small gap to its neighbours for drainage.
  4. Fasten with exterior/corrosion-resistant deck screws into each joist; seal cut ends of pressure-treated lumber with an end-cut preservative.
schedule45 min savings$15–60
Replacement deck boardMatch the width, thickness, and material (pressure-treated or composite) of your existing boards Corrosion-resistant deck screwsRated for exterior / pressure-treated lumber
gavel Check your province first AB: permit + inspection required · BC: permit + inspection required · ON: permit + inspection required · PE: permit + inspection required · QC: permit + inspection required
Replacing a single surface board is routine homeowner maintenance.

verifiedWhy this one goes to a pro

Rotted joists, a failing ledger, or a bad post/footing carry the whole deck and the people on it. These are assessed and repaired by a qualified contractor — often with a permit — not patched from above. Keep the deck clear until it's been checked.

Your notes travel with the request — what you saw, what you ruled out, when it started — so the pro arrives with a head start instead of a mystery.

verifiedWhy this one goes to a pro

Rotted joists, a failing ledger, or a bad post/footing carry the whole deck and the people on it. These are assessed and repaired by a qualified contractor — often with a permit — not patched from above. Keep the deck clear until it's been checked.

Your notes travel with the request — what you saw, what you ruled out, when it started — so the pro arrives with a head start instead of a mystery.

verifiedWhy this one goes to a pro

Rotted joists, a failing ledger, or a bad post/footing carry the whole deck and the people on it. These are assessed and repaired by a qualified contractor — often with a permit — not patched from above. Keep the deck clear until it's been checked.

Your notes travel with the request — what you saw, what you ruled out, when it started — so the pro arrives with a head start instead of a mystery.

sort

Why the list is in this order

We don’t sort by likelihood alone. We sort the way a good, honest tradesperson thinks: rule out the free, safe, common causes first. That’s why the cheap checks outrank the expensive repairs — and why anything dangerous gets a hard stop instead of a pep talk. The order exists to save you money, not to sell you anything.