Welcome to another Q&A session where we answer questions from homeowners around Maple Valley and King County.
Today's question is:
The owner explains that the biggest contrast between a climate like Arizona's and Washington's is extreme sun versus extreme rain. Certain deck types, particularly synthetic membrane or fully sealed decks resembling a rooftop deck surface, are never a good fit for Washington because water inevitably finds its way through the material, flashing, or the sides of the house, eventually destroying the framing underneath. He sees this issue constantly and notes that while these sealed surface decks work fine in a dry climate like Arizona because there's no water intrusion risk, they consistently fail in Washington's wet conditions. His clear recommendation is to avoid sealed, solid-surface decking systems entirely in this region, since they reliably lead to long-term structural problems.
That's a great question, and it's something I've talked about hundreds of times over the years, and for whatever reason it's been coming up a lot lately. The difference between a place like Arizona and Washington is the rain versus extreme sun. In Washington, there are types of decks that, no matter what you do or what product you use, are going to have issues and just aren't ideal for this climate. A good example is a synthetic membrane deck or a completely sealed deck, kind of like a rooftop deck, where you walk out and it's not composite boards or deck boards, it's just one membrane surface. Those will never hold up over time in Washington, because water always eventually finds its way through the material, through the flashing, and through the sides of the house, and it eventually destroys the framing below the deck. This is an extremely common issue that I see almost every day. In a place like Arizona, that kind of deck is actually a great option, because it's cost-efficient, you don't have to buy expensive composite decking, and you don't have to worry about water ruining the deck or the framing below it. So that's probably the best example. There are a few other smaller things that work in Arizona but not here, but overall, these sealed, solid-surface decks are just not good options for Washington State. They always end up with issues, and I would never recommend them to anyone in this climate.
