The screwdriver test
Walk every joist line and push a screwdriver into the boards every couple of feet. Sound boards resist; rotten boards take the screwdriver easily. If the screwdriver sinks deeper than 1/4 inch with normal pressure, that board is structurally done — replace it.
Visual signs to scan for
- Cupping (boards curling up at the edges): usually water trapped underneath. Replace if severe.
- Splitting at the screw heads: cosmetic but can spread.
- Dark soft spots: rot. Replace.
- Wood looks fuzzy / gray: just weathering. Power wash and stain if you like, but structurally fine.
- Mushroom growth: the wood is decaying. Replace those boards plus check the joist below.
Don't forget the joists below
Boards age more visibly than joists, but when boards rot, water has been sitting on the joists too. Always look down at the joist when you pull a rotten board — if it's also soft, that's a bigger job. We can do partial joist replacement if it's just a few; full deck reframe if widespread.
When to replace the whole deck instead
If 30%+ of boards need replacement, full re-deck is usually cheaper per square foot and looks better than a patchwork. Full re-deck (boards only, existing frame) runs $8–$15/sq ft installed in our area.
