Warped, cupped or lifting deck boards
Boards that bow, cup or lift at the ends are telling you something about moisture or fixings.
Why it happens
Boards cup when the underside stays wetter than the top, common on balconies where water pools on the slab. They bow or lift when screws corrode, clips snap, or boards were laid too tight with no expansion gap. Composite boards also swell if they sit in standing water.
How we fix it
- Check drainage under the deck and clear the floor trap
- Re-fix lightly warped boards with new stainless screws
- Replace badly cupped or split boards
- Sand the surface flat and re-oil
Get it quoted
Send us photos of the affected area on WhatsApp and we will reply with a quote. More on our deck board replacement service.
Questions about this problem
Can warped deck boards be straightened?
Mild cupping can be sanded flat once the board dries out. Strongly bowed or twisted boards should be replaced.
Why are my composite boards warping?
Usually heat expansion with too-small gaps, or water sitting under the boards. Fixing the gaps or drainage stops it recurring.
Other deck problems
Not sure if your deck needs a repair or a full replacement?
Send us photos on WhatsApp. We will tell you honestly whether a sand-and-oil, a few new boards, or a full re-lay makes sense, and send you a quote.