We bought a brand new house in 2015.
Fall of 2015, we put Thompson's water seal on the top of the deck. I am learning that this was a mistake and it should have been applied to ALL sides of the deck apparently (according to a DIY friend)?
I am not sure if this is what caused it but now after 2 winters, the deck pops and creaks terribly every time we walk on it (of course, maybe not the winter that caused it but last spring it was pretty bad and this spring, even worse).
I noticed also that some of the screws used to fasten the wood to the deck supports are actually going inside the wood (the screw heads seem to be sinking in to the wood).
Maybe the problem is twofold but I also see some moisture buildup on the underside of the deck when I look up at it from the patio.
I read another thread and people said it may be caused by too much movement in the deck (could the screws sinking into the wood cause that)? Another suggested remedy was to remove each board one by one and put glue down on the joists, then replace with 3 1/2" deck screws but I want to get some help from DIYers first.
I'm honestly not sure what type of wood it is by the way, looks like some treated lumber.
How can we fix it? Thanks a lot!