Saw the deck from hell yesterday. Massive area in an 'L' shape - size of a badminton court. Bouncing, springing, creaking, uneven. Been there for a couple of years, guy who built it has vanished.
Lifted a couple of boards to find;
Supporting joists are 4 x 2 timber instead of 6 x 2. The 4 x 2 joists span between 15' & 20' without support and bounce when walked on - you can see them deflect.
The joists are also spaced too far apart. I usually space them at 16" centres, these are at 36" centres, so the boards give under load.
What is needed is some extra support. I'm trying to think of a way of adding this without pulling up every single board.
Any ideas?