Building a deck now in hot South Carolina. I purchased #1 premium deck boards very nice appearance no knots etc.. The boards are very wet and even though I was sure to put them in the bark up position some are cupping because of the high heat of the summer sun. I think the rapid drying conditions are causing this. Is there a recommendation for slowing the initial drying phase?

I am going to stain the deck but everything I’ve read says not to do so for months or even a year after install.

2 Answers 2


Ideally a person would hold off using freshly treated lumber and let it dry out in a controlled stable environment. At this point, after installation, I think I would try to keep it out of direct sunlight. If at all possible, put up some sort of a sunscreen to prevent the rapid drying of the surface. You might even go so far as to lay down a lightweight, fast drying carpeting while the wood dries out.

If it's drying out that quickly, I see no reason why you wouldn't go ahead and apply a good quality penetrating sealer. The wood will continue to dry out from below and the edges over time, but at a slower, less damaging rate.

  • I covered one section with plastic for a few days it is drying with much less distortion. I like the idea of lightweight mats for blocking sun.
    – Kris
    Commented Jun 9, 2018 at 16:35

To keep your deck boards from cupping and splitting, it needs to be installed correctly: 1) two fasteners at EACH support (screws are better than nails and they should penetrate at least 1 1/2” into support), 2) keep fasteners about 3/4” from edge of deck board to keep it from cupping, 3) pre-drill fastener holes at end of boards to keep it from splitting, 4) provide a double joist at end of deck pieces locations.

Use an oil-based penetrating “deck” stain to protect the wood. Follow the manufacturer’s instructions, but do not allow the wood to age and discolor. Do not install carpet, mats, etc. on the deck because it will discolor the boards and show an outline of where the mats were located. (Stain will not cover this discoloration.)

  • .I used all of those good techniques fir fastening however the direct sunlight and 90-95 degree heat is cooking the deck boards like bacon in a microwave. I don’t intend to leave the boards covered for longer than a week or 2. Just to slow evaporation. Or would it be wise to keep wetting the boards fir a few days to slow down the drying?
    – Kris
    Commented Jun 9, 2018 at 17:39
  • @Kris I live in a very mild climate, so I don’t know local customs for resolving this issue. However, we do use a modulating sprinkler to slow the drying process in freshly poured concrete slabs. However, if water puddles on the deck boards it could cause stain marks. I’d be careful.
    – Lee Sam
    Commented Jun 9, 2018 at 18:29

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