Even in the northwest where extreme heat is not usually something which we experience, your deck needs attention to stay strong and beautiful. When the seal on your deck is exposed to the elements of the weather, it deteriorates over time. As the seal deteriorates, the wood then takes the brundt of punishment from the sun, wind, rain and snow. As bare wood is exposed to the elements it will in time start to crack and warp. If left for too long, repairing boards may be necessary. If left for a very long time, the whole deck will need to be replaced!