Q. We had a composite deck (Fiberon) installed about two years ago and now it has many black spots and stains that we have been told are mold and mildew. What is the best cleaner for the deck and is there a way to keep these stains from returning?
A. Many types of materials, including composite decking, can develop mold and mildew if the right conditions exist – mainly moisture, lack of sun and, in the case of decking and other horizontal surfaces, failing to remove leaves and other debris that can serve as food for mold. There isn’t really any permanent preventive.
Your experience should also give notice to other composite deck owners and prospective buyers that this material, which is a blend of wood fibers and plastic, is not maintenance-free, as is sometimes suggested. Since your deck is relatively new, it will still be in warranty and your best bet is to contact the manufacturer about the best cleaner. Contact and maintenance information is listed on the Fiberon Internet site, www.fiberondecking.com.>
Regular cleaning with a blower or broom is recommended, along with “soap and water” if needed. Pressure washing is not recommended for removing mold and mildew, but a product called 30-Second Outdoor Cleaner is mentioned as a mildew-mold treatment. Fiberon’s warranties cover stain resistance on several types of decking, but this applies primarily to stains from food and drink spills.
In general, composite decking does have some advantages over pressure-treated wood. Composites won’t rot, split or splinter and don’t require stains or sealers. Treated wood also resists rot for many years, but even the best wood will often develop small cracks as the waterborne preservative dries out. Treated wood is much stronger structurally than composites, and the supporting structure of most decks is built of treated wood. Composite decking also usually costs three or more times as much as treated wood.
Homeowners building decks need to look at the whole picture before choosing decking. If a composite is the choice, keep in mind that low-maintenance is the correct description, not no-maintenance.
Q. We have a lot of white residue in our dishwasher, and the dishes also have a film on them. We use the rinse and have tried many detergents. We also put a filter on our well but it hasn’t helped. What can we do about this?
A. The white residue is probably deposits of calcium and magnesium compounds from the hard water coming from your well. The deposits, if continued, can also damage, stain or clog your other water-using appliance and fixtures.
Your best bet is to have the water tested and, probably, install a water softener. As I pointed out in a recent column, you should be able to get a free water test from water-softener companies in your area, but you will also get a hard sell for their brand of softener.
If you would prefer an independent water test, you can find laboratories on the Internet (search for Water Testing) or possibly in your yellow pages. Water softeners change the chemical composition of the water by altering the harmful compounds.