Tip of the Day: Get rid of roof algae, which can damage shingles

Rooftop gardens have been touted as a type of cool roof that can help reduce energy use and costs. But one plant life you don't want to see on your roof is Gloeocapsa magma, a blackish algae that thrives on moisture seems to have an affinity for material used in some roofing products. When left unchecked, it can damage shingles.

This algae creeps its way upward on roofs, gradually turning shingles dark brown or black. It's easy to spot along some east-west streets with lots of trees, and sometimes it's present house after house.

My wife and I recently noticed Gloeocapsa magma algae on our 10-plus-year-old roof (shown), as well as lichens, which look like greenish-white splotches made with a paintbrush. Fortunately, we didn't have any other growth, such as moss, which can dig in beneath the shingles and upgrade the buildup from two- to three-dimensional.

I looked into some DIY solutions to eliminate the algae, such as oxygen bleach. But the safer, more-prudent move—especially with bursitis in one of my shoulders—was to hire a pro who'd do the job at a reasonable price and not use the chlorine-bleach solution the Asphalt Roofing Manufacturers Association recommends (PDF), which can damage vegetation around the house. (Note: If plants and grass are watered before applying the bleach solution and if the bleach solution is applied correctly, vegetation shouldn't be harmed by the cleaning.)

Pricing for a good roof cleaning, according to Baltimore's My Clean Roof, is based on many factors, including roof height, roof pitch and angles (not all roofs are walkable), and the algae species involved. We got a wide range of cleaning quotes, from a few hundred dollars up to $1,200.

We also spoke with one fellow who wanted to pressure-wash the roof (not recommended), and another who wanted to install copper or zinc strips without washing first. While using the strips would provide a long-lasting solution to the algae problem, the $1,500 price seemed way too high.

In the end, we found a roof-shampooing franchise operation, which quoted us a price of $350. We agreed to the price this past Monday evening, and the work was done two days later. (The cleaned roof is shown, right.) The company even threw in cleaning the siding of the two front dormers and gave a one-year warranty on the work.—Ed Perratore | e-mail | Twitter | Forums | Facebook

Essential information: If you need a new roof, read our latest report on roofing materials and find the best product for your home in the ratings (available to subscribers).

Q&A: Why are some of the Kilz exterior paints you tested no longer in stores?

I referred to your magazine and ConsumerReports.org when shopping for exterior paint, but at my local Walmart I can't find the Kilz Exterior Semigloss paint from your June 2009 ratings. What happened to it, and do you recommend the Kilz Casual Colors I saw at Walmart?

Manufacturers frequently change the formulation of their paints and stains for a number of reasons, including to improve performance, lower production costs, or meet updated environmental standards, as we covered in our March 2009 report on interior paints.

The Kilz Exterior Semigloss paint we tested is no longer available at Walmart, exclusive retailer of the brand, because Kilz recently discontinued the satin and semigloss versions of its interior and exterior products. The company has replaced those paints with the multipurpose interior/exterior Kilz Casual Colors paints you saw in the store. For more information, read our June 2009 report on exterior paints and stains and see our ratings of exterior paints and stains (available to subscribers).

Although Kilz products have generally performed well in our past tests, we can't predict the performance of these new finishes. We plan to test the interior- and exterior-use versions of the new Kilz Casual Colors this year. Given our test cycle, we won't have initial results on the performance of the exterior paint until 2011 but should have initial results for interior paint by March 2010.

Among alternatives to the Kilz semigloss paint to consider for exterior application are the Kelly-Moore Acry-Shield Semigloss ($37 per gallon), available in the Southwest, and the Valspar Ultra Premium Semigloss ($26), sold at Lowe's nationwide. And while testing is not complete, the Behr Premium Plus Semigloss ($26), sold at Home Depot, and the Ace Royal Shield Semigloss ($25) look very promising after the equivalent of six years of use.—Ed Perratore | e-mail | Twitter | Forums | Facebook

Essential information: Visit our paints page for details on specialty paints, tools you'll need for your project, and tips on avoiding common painting mistakes.

Q&A: How can I tell a water-based paint from an oil-based one?

I've read that water-based paints are easier to clean up than oil-based finishes. How do I know whether I'm buying a water-based or an oil-based paint?

About 80 percent of paint sold today is water-based; the rest is oil-based. Oil-based paint is considered more hazardous than water-based paint because the solvents used to make it are toxic and flammable. Note that you can recycle both types.

Water-based paint often has the word "latex" as part of the product name. Ingredients include water and ethylene or propylene glycol. Water is indicated for cleanup.

Oil-based paint often has the word "alkyd" as part of the product name, and the label will indicate "caution" and "flammable" or "combustible." Ingredients include petroleum distillates or mineral spirits. Cleanup method indicates the use of paint thinner, mineral spirits, or turpentine.

Essential information: Fall is a great time to tackle interior-painting projects. If you're painting rooms inside your home, read our latest report on interior paints (article and ratings available to subscribers) and visit our paints page for details on specialty paints, tools you'll need for your project, and tips on avoiding common painting mistakes.

Q&A: How frequently do I need to reseal my granite kitchen countertops?

My contractor told me I should reseal my granite countertops periodically to protect them from stains. How do I know when it's time to reseal them?

Granite, limestone, and marble countertops are all different, so check with the fabricator to see what the recommended time period for resealing is. But if your kitchen countertops get a lot of use, the general rule of thumb is to reseal them every six months, according to Andy Graves, of the Fabricator Network trade group. Graves suggests you do a water-absorption test to get an idea of how fast water is penetrating the stone and whether the counters need resealing.

To test, put a few drops of water on the stone in high-use areas, such as around the sink and range or cooktop, and let the water stand for 15 minutes. The water should bead up. If it doesn't, it's time to get the granite resealed.

You can also use this test on butcher block and other wood countertops that have an oil finish. You do not need to reseal a wood counter with a polyurethane finish, however when this finish is worn or damaged, repair or refinish it.—Kimberly Janeway | e-mail | Twitter | Forums | Facebook

Essential reading: Read our latest report on countertops and check out the ratings (available to subscribers) to find the best material for your home. If you're remodeling our kitchen, use our updated Kitchen-Planning Guide.

Hurricane Bill and the Midwest tornadoes: Short- and long-term planning

Hurricane Bill is strengthening before a possible landfall on the Canadian Maritime coast, while Midwesterners are weathering severe thunderstorms in the wake of Wednesday’s tornadoes that struck parts of Minnesota and Nebraska.

These recent posts can help you cope with natural disasters of all kinds:

• Our Storm & Emergency Guide includes articles, downloads, and videos on the products and procedures that help you assess your risk and plan proactively.

• The National Oceanic and Atmospheric Administration recently issued an updated forecast for a below-normal Atlantic hurricane season but noted a past history of severe storms late in the season.

• Many insurers have reduced coverage and increased deductibles for perils like wind storms and hurricanes, making it even more important for you to make wise decisions about additional flood insurance. Watch the video above for more on flood insurance—Gian Trotta | e-mail | Twitter | Forums | Facebook

Q&A: How can I deal with lawn fungus?

After all the recent heavy rain we've had, several brown spots have appeared on my lawn, and they're spreading. Neighborhood dogs aren't causing the problem. Is my grass suffering from some kind of fungus?

Based on the photograph you sent us (shown), it looks as if your yard does have a fungus problem. Even if you took good care of your lawn earlier in the growing season, excessive water can damage grass and foster fungus growth.

To identify a fungus in your yard, use our guide to common lawn problems and visit the Cornell Cooperative Extension Web site. The CCE is a nationwide network of agricultural and environmental specialists based in Ithaca, New York.

Your next step is to apply a recommended fungicide to and around the infected area to keep the fungus from spreading.The CCE advises that you use the right product for the fungus problem you have and closely follow application instructions and precautions. When mowing, cut the healthy parts of the lawn before the sick, and bag and dispose of clippings to avoid spreading the fungus with your mower.

Proactive application of a general fungicide when the temperature first starts to rise in the spring, as recommended by our lawn-care expert, Peter Sawchuk, might prevent fungus problems altogether throughout the growing seasons, although you also need to take any possible measures to keep your lawn from encouraging fungal growth in the first place. Sawchuk buys fungicides in the fall since these products tends to be scarce in stores in the spring, when they're needed the most.

If you're in the market for a new lawn mower or tractor, read our latest report on this outdoor power equipment (story and ratings available to subscribers) and visit our mower/tractor product page.—Ed Perratore | e-mail | Twitter | Forums | Facebook

Essential information: Water your lawn early in the morning, which lets the water settle in with less evaporation and protects your grass against the brightest, hottest part of the day. Watering late in the day could make your lawn susceptible to such fungi as brown patch, Pythium, and rust.

Q&A: How can I estimate how much roofing we'll need?

We're planning to replace our roof later this summer and want to get some ballpark estimates from a number of pros. How can I estimate how much roofing we'll need?

Knowing how much roofing material you'll need will make it easier to compare bids from contractors.

Roofs are measured in 100-square-foot areas, or squares. A square of three-tab shingles is typically three bundles, while for laminated shingles a square is usually four bundles. Read our latest report on roofing, which includes ratings of more than two dozen products and expert buying advice (report and ratings available to subscribers).

To gauge your needs, multiply the overall length and width of each section of your roof to determine the square footage, adding 10 percent to allow for waste. Then divide that number by 100 to determine how many squares the job will require.

If you don’t want to go on your roof to get accurate measurements, you can estimate the roof surface area by using the length and width of your home as the basis. Increase each of these dimensions by the amount the roof overhangs the exterior walls on each side of the home. Since the roof might have distinct sections and because most roofs are pitched, you'll want to increase the number you calculate. Adjust the calculated area by about 5 percent for a low-sloped simple roof to about 40 percent for a complex roof design with a steep slope.

When you get bids, be sure the contractor includes the cost of the underlayment (roofing felt), which creates a moisture barrier for the wood sheathing and rafters underneath. And don't forget to factor in adding an ice-and-water shield, which runs along the eaves and the valleys where two wings of the roof intersect, as well as new drip edges and metal flashing, which are often needed around pipes, chimneys, and the like. e-mail | Twitter | Forums | Facebook

Weekend Project: Sharpen your mower blade

For our second weekend project, we're focusing on the blade of your lawn mower. As mentioned in the first installment of this series, we're running these items early in the week so you can get them on your to-do list early—and perhaps free up time for some R&R this weekend.

If you didn't sharpen the blade on your lawn mower at the start of this mowing season, or if you've been doing a lot of cutting so far this spring, now's the time to hone the cutter. And remember, you should sharpen the blade every year, more frequently if you have rocky or sandy soil. (If you're in the market for a new mower or tractor, read our latest report on this outdoor power equipment, available to subscribers).

A sharp blade not only cuts grass more cleanly but also trims fuel costs by up to 25 percent. Yet more than a quarter of Americans surveyed in our latest poll about lawns admit they've never sharpened their blade. That's a lot of gas money being left on the table not to mention butchered grass blades leading to ugly, unhealthy lawns.

Here's how to remove and sharpen the blade:

1. To remove the blade, turn the mower on its side; tip the mower so that the air filter faces up to keep engine oil from saturating the filter. To prevent a fuel spill, remove the blade once the mower has run out of gas or siphon off the gas. For good measure, remove the spark plug so there's no chance of the blade suddenly spinning to life.

2. Wearing heavy work gloves, secure the blade by lodging a block of 2x4 block between it and the mower deck (shown). Then use a combination wrench to loosen the bolt that anchors the blade to the drive shaft (there might be more than one bolt). If the bolt sticks, hit the handle of the wrench with a rubber mallet or use the breaker bar from your socket set for added leverage. Never be in a position where your hand or arm will contact the blade if the wrench or socket slips off the bolt or nut. Be sure to put the hardware in a safe place until remounting so you don't lose it.

3. Bring your blade into the local hardware store or power-equipment shop, where a sharpening will run you $5 to $10. If you get to the store before it gets too busy, they might be able to sharpen it on the spot, allowing you to get down to the real weekend project: cutting the grass. While you're at the store, pick up a second blade ($15 to $20). That way you'll always have a sharp blade on hand. Check the owner's manual before you head out to be sure you buy the right blade.

You could also sharpen the blade on your own using a metal file or a bench grinder, but it takes a steady hand to hold the blade at just the right angle and balance it without damaging the blade or hurting yourself.

4. When you remount the blade, be sure its cutting edge follows the direction of rotation—the wings of the blade will be oriented up toward the mower deck. If the mower has a cup washer, make sure the cup is facing the blade. Tighten the bolt according to the manufacturer's specifications.

Another good sharpening option is Dremel's Lawn Mower & Garden Tool Sharpener attachment (about $8) is. Peter Sawchuk, our outdoor-power-equipment expert, uses this attachment at our mower/tractor-testing site in Fort Myers, Florida, where we check out several dozen models every year. "I see value in the attachment for homeowners," says Sawchuk, noting that the nylon guide holds the blade at the right angle for maximum sharpness. In Sawchuk's experience, the only drawback to the attachment is that it can't grind out major nicks. You can also get similar drill attachments for sharpening a mower blade. Properly clamping the blade in a stationary position and using two hands to guide the tool will help you get a uniformly sharp cutting edge.

Even if you have to buy the rotary tool—a basic Dremel kit with a compatible model costs about $45 to $100—it will pay for itself in two or three years.—Daniel DiClerico | e-mail | Twitter | Forums | Facebook

Essential information: Read our additional tips for saving money while maintaining a lush, healthy lawn. And check out our mowers and tractors buyer's guide.

Protect Your Investment: Consider climate when building a new deck

If summer has taken a toll on your deck and you plan to replace it this fall or next spring, wouldn't it be nice to have a crystal ball to predict how long the deck will last, whether its color or grain will fade in the sun, or whether mildew stains will appear on shade-covered parts?

To get a glimpse into how well the almost two dozen different decking materials we recently tested might do after a year in different conditions, we left samples of each in Florida (warm, humid climate) and in Arizona (warm, arid climate); as a reference, we also kept a sample of each indoors in our labs.

(From left to right, the columns in the photographs here show the decking after one year stored in our lab; in Florida; and in Arizona. The five rows from top to bottom show the decking unwashed; washed with water and a brush; washed with OxiClean and a brush; washed with Behr wood cleaner; and cleaned with a pressure washer.)

Our testing indicates that rain and humidity foster the greatest mildew growth on composite decking materials. ChoiceDek (shown above), Monarch Exotics, Fiberon Tropics, Rhino Deck Vision Solid, and Trex Brasilia and Accents in particular showed mildew growth after a year in Florida. Symmatrix, Tamko EverGrain, and TimberTech stood out as the most resistant to mildew. Still, if you're concerned about mildew, consider using a deck stain formulated for composite decking. Also check whether the manufacturer claims its product is mildew resistant.

When it comes to wood, unless you apply a finish to preserve a wood deck—we recommend you treat a newly installed deck within a month of installation—it could turn an off color after a year or less. (Our wood decks turned gray in Florida, brown in Arizona.)

Color change in untreated decking isn't confined to wood. Trex Accents and Rhino Deck Vision Solid underwent the most dramatic color shift among composites. The plastic decking, including Deck Lok, Eon Classic, and Bear Boards, and the aluminum LockDry (shown right) we tested experienced little color change, and nearly all did an excellent job resisting mildew.—Ed Perratore

Essential information: For more details, visit our Decks & Deck Stains product page. And use our Outdoor-Living Guide to get the most out of your yard and deck, patio, or porch.

Q&A: Should I have my home tested before I put it on the market?

Should we test our older home for radon, mold, and lead before trying to sell it? Would this help us stand out in a tough market?

We spoke with three regional vice presidents of the National Association of Realtors—each with more than three decades of experience selling homes in up and down markets.

"Buyers want to get their own tests, and they tend not to believe the seller's tests," says Mary Davis, a real-estate agent in River Edge, New Jersey. John Veneris, a real-estate agent in Downers Grove, Illinois, adds that home buyers should "wait until the general inspection to resolve any problems."

Robert Bailey, a real-estate agent in Santa Cruz, California, suggests that before homeowners put their house on the market, they get an idea of what problems exist by doing a general and pest-control inspection, along with a visual inspection for such problems as mold. (Keep in mind that mold-testing kits proved generally ineffective in Consumer Reports testing. Lead and radon kits fared better although quality varied in some cases very widely between brands.)

But time and money invested in home repairs and regular maintenance can pay off when it's time to sell. Water damage and cracks in the foundation won't go away and could be a deal breaker. A general professional home inspection is not required, but recommended as part of the selling process. And a property condition disclosure form is required in 44 states and the District of Columbia, according to NAR spokesman Walter Molony.

Buyers should be aware that Alaska, Arkansas, Kansas, Vermont, West Virginia, and Wyoming do not require this form, but federal law mandates that any seller of a house built before 1978 must disclose if lead paint was used as an interior or exterior finish.—Kimberly Janeway

Essential information: Find out why staging your home might help close the deal and how to get the most for your house in a soft market.