I have built a deck recently ( a couple of months ago) using Merbau. What I have noticed is that especially during sunny days when we walk on the boards it gives a noise and a feeling that the boards are not screwed/tighten properly. And I find that the screws are a bit loose during sunny days. I hope this happens due to expansion and contraction. ( FYI, during humid or winter days I could not notice or feel this). I have used Zenith Decking screws T17 Countersunk 65mm. Pic is attached here for your reference.
My question is, once you build a Merbau deck after some time is it required to re-tighten the screws or just leave it as is? is this common? If I re-tight them again, during humid conditions would it create any issues?
This is often one of the most neglected maintenance steps that need to be done on your deck. I recommend waiting until your deck has dried out before re-tightening your deck screws. If it's done while the decking panels are full of moisture, the screws will not reach their original sitting spot in the timber. My number one tip for this activity is to set the torque setting on your cordless driver to a low setting so that you don't overdrive the screw into the decking panel.
Let me tag our experienced members @LePallet and @Brad for their recommendations.
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