Azek decking boards not sitting flush on joists

My contractor has laid the azek floor boards. The clip system, no screws. My question is should the floor boards be perfectly flush. Some are not, they are not overly noticeable, but as the homeowner I do notice. Also the floor boards do not sit directly on all the joists.

Is there any reason for concern for either issue?

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Aug 30, 2020
Wavey NEW
by: Les Ismmore

Have you seen the lack of quality of wood now days?

Composite wants straight joists; it is not as forgiving as wood. Irregularities will show. Shimming may still be necessary. On our job, 5ft. levels were used to check the plane.

This could be a good argument for metal joists.

Another problem can be too tight of an abutment gap during installation in cool/cold weather. When it warms up, composite will expand lengthwise, thus a lateral wave.

Oct 18, 2011
Check fasteners and joist framing
by: Editor - Rich Bergman

Even if you are using a clip system the boards should still sit flat on the joists. Something doesn't sound right. Maybe the fasteners were not installed quite right. Or it may be that the joists themselves have significant bows or crowns in them and sit high or low relative to each other resulting in the tops of the joists not lying in the same horizontal plane.

Tough to say for sure without pictures but my first look would be at the way the fasteners were installed, then check the joist framing.

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