RALEIGH — Most people have some sort of deck on their homes, and most are made of wood. To make the wood last, it has got to be protected with some sort of stain or sealant.

Consumer Reports

checked to see which deck treatments work best.

This is something deck owners do every few years if they use a good sealant. To find out which deck treatments protect wood the longest, Consumer Reports has been doing a long-term tests. They show some products look bad in less than a year.

Testers treated deck boards with a different protectant product. They were then left out in the weather -- some for a year while others for as much as four years. Even in that short time, many started showing problems.

At a second test site -- this one in the shade -- boards were checked to see how well treatments resist mildew. In just a year, some are covered with mildew's telltale black spots.

In both tests, the worst performers are the popular clear treatments, the kind that lets the grain of the wood show through.

"Generally, they last a year to two years. Some of them don't even last a year. What it means is every spring, you're going to be out there with a power washer, cleaning your deck and re-applying," says tester Charlie Spatola.

If you really want a clear treatment, the best tested were from Olympic: Olympic Clear Wood Preservative and Olympic Water Guard. By far, the longest lasting treatments are the opaque stains. Those are the kinds that color the boards and look the most like paint.

Consumer Reports says one good choice is Cabot Decking Stain. If it is used on a deck, testers say it shouldn't need to be treated again for four years.

Consumer Reports tests show several of the biggest selling products do not look good for very long, so Consumer Reports does not recommend them. They are Thompson's Water Seal and Water Seal Ultra and Wolman Rain Coat Water Repellant.