Dear Glenn: Beginning last summer, I noticed some dark streaks and patches on the roof of my house. When an addition was put on our house about a year ago, the guys doing the work said the roof was in really good shape. The previous owners did a complete tear off with new roof in August 2000. Perhaps the roof just needs a really good cleaning?

John, via e-mail

Dear John: The dark streaks are very common and may be mold or mildew. You can use a product called Moldex Deep Stain Remover, (877) 463-2628, www.moldexbrands.com, followed by Moldex Protectant, which will slow the mold from coming back.

Dear Glenn: We're painting in the next two to three months. I'd like to buy the eight gallons we'll need at the store within the next few weeks. I will not be near this store at the time of painting. How long is paint good for? Thanks for your help.

Peter, via e-mail

Dear Peter: According to the people at Shelby Paint and Decorating, (586) 739-0240, www.shelbypaint.com, in Shelby Township, if the paint is stored correctly, it can last up to 10 years. Stored correctly means, don't let it freeze.

Dear Glenn: I noted in an earlier column you recommend blown-in cellulose insulation for attics. Will you recommend an installer in the Northville-Livonia area?

Robert, via e-mail

Dear Robert: I would place a call to Ace & Sons Insulation, (888) 500-4223, www.aceandsons.com. They have been serving the Metro Detroit area since 1981. Remember to inquire about the many tax credits that you can receive from the state of Michigan utilities program plus federal and state programs.

Dear Glenn: I bought three Germ Guardian UV-C wands from Costco for myself and my two kids. It is a laser-type wand that disinfects when you turn it on and wave over items like my cutting board. It also kills dust mites in the bed mattress. Do you have an opinion on this item? Does it work?

June, via e-mail

Dear June: It's no laser. It's ultraviolet-C lights. I think that it is such a good idea to help disinfect items that I bought four of them myself. Costco prices are the lowest that I have seen.

Dear Glenn: How we have enjoyed your expertise over the years. We now live in a modest condo in Mount Pleasant. Some of our neighbors have purchased small heaters of some kind and use one on each floor. I believe they are plugged into the electric outlet and can be moved about easily.

They say their gas heating bill has been lowered dramatically. In fact, one neighbor has not had to use his gas furnace yet this season! They ordered their two units either online or by phone and received them by UPS. I believe some of these heaters are made by the Amish folk. Can you research them, if you haven't already, and tell us about these units? Are they safe and a good boost for heating?

Georgean, Mount Pleasant

Dear Georgean: These types of heaters are safe if they are UL-rated. However the types of heaters that I prefer are the ceramic-style space heaters. Check out Pelonis, (866) 876-4332, www.pelonis.com, the inventors of ceramic disc heaters. They have their Safe-T-Furnace style ceramic heaters. You can also find Pelonis heaters at your local ACE Hardware stores. Their price has come down a lot. Now they are under $40 for most models, and they provide 5,100 BTUs.

Dear Glenn: Our sewer pipes keep getting clogged with tree roots every six months. Your answers on your radio show to similar questions have been to call a Roto-Rooter type company to get PVC pipe lining put in. Do the roots ever stop growing? A camera did show roots once, and I am dreading a repeat of an overflowing toilet in our two-story home in California. I just needed to know if it's absolutely necessary to fix it or wait and watch.

Pravin, California

Dear Pravin: Sewer lines can and should be hydro-jetted, not just snaked. No chemicals, just high-pressure water clears the entire inside diameter of the pipe. Follow up with a camera inspection of the sewer. For a local referral to a company in your area and for more information on the technique, I suggest you call Rooter MD, (800) 766-8376, www.rootermd.com. Talk to Pete Wood.