Flaunting your deck’s natural wood grain is one reason to consider a semitransparent treatment over one of the longer-lasting opaques. A more translucent finish can also protect you and your family from arsenic if your deck is more than three years old.

Until 2004, most decks used lumber preserved with chromated copper arsenate (CCA) to fend off rot and insects. CCA was replaced with other preservatives for residential use amid concerns that it could leach out. Semitransparent coatings penetrate the wood and seal in that toxin, according to the Environmental Protection Agency. Opaque finishes also seal well, but they might peel or flake and require sanding, which can spread arsenic-laden dust from CCA lumber.

Longer-lasting treatments that still look good after three years of sun and snow also make a case for showing off the wood. Here are our latest findings:

A semitransparent with stamina. Tinted, semitransparent treatments blend some of a clear coating’s appeal with some of the best opaques’ staying power. While most needed refinishing after only two years, the Wolman Dura­­Stain 18146 looked nearly as good as the top opaques after three years and held up better than some other opaques.

A clear coating worth considering. Clear finishes show the wood grain with little or no tinting, though they typically require the most refinishing. An exception: Olympic’s WaterGuard 55560, which looked better than some semitransparent treatments and even a same-brand opaque after three years.

Several strong starts. We test deck treatments year-round on hundreds of deck boards for up to three years or until they’re weathered enough to need refinishing. Two opaque coatings from Ace and Behr looked excellent after their first year, while a Flood opaque looked very good after two years.