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).

The MythBusters look at destructive force of hurricanes

You might not be able to fool Mother Nature, but based on an episode of MythBusters that ran last night on the Discovery Channel, it might be possible to at least work in conjunction with her.

With Hurricane Ida in the news and preparing to make a mess of the weather on parts of the country even as it was downgraded to a tropical depression, MythBusters aired its "Hurricane Windows" show, in which hosts Adam Savage and Jamie Hyneman investigate whether you can lessen the damage caused by a storm by leaving windows open on a trailer or a home.

In typical MythBusters fashion, Savage and Hyneman pulled out all the stops to determine the veracity of the myth, even using the University of Florida's wind machine to create hurricane-force winds. No spoiler alert here: Watch the different parts of the episode on the show's site to see what happens. (The screen shot shows the duo observing a trailer getting battered by Category 2 winds.)

The 2009 Atlantic hurricane season, which wraps up at the end of November, has seen lower-than-normal activity, as noted in our August storm-season update and as reported on Weather.com: "2009 will go into the record books as a very uneventful hurricane season, except for late season Ida." To be prepared for a weather-related event no matter when it happens, use the advice on our Storm & Emergency Guide.—Steven H. Saltzman | e-mail | Twitter | Forums | Facebook

Essential information: We haven't tested roofing shingles or siding for their ability to withstand hurricanes or tornadoes, but our reviews of these building materials can help you find products that will look good and last. Watch our video on how we test shingles.

Detroit house to be turned into giant ice cube

You might have heard about or even had to deal with ice dams, those frozen build-ups around the eaves of a home that can damage roofing and siding during winter (see illustration). In Detroit, two artists are taking the concept of the ice dam to the extreme, and perhaps that's appropriate in a city known as Hockeytown, USA.

Architectural photographer Gregory Holm and architect Matthew Radune plan to encase one of Detroit's thousands of abandoned homes in ice this winter, according to this Associated Press report. Through their Ice House Detroit project, Radune and Holm want to draw attention to the staggering number of foreclosures in the city.

(Michigan saw the eighth most foreclosure activity in the third quarter of 2009, says RealtyTrac. And according to the latest Standard & Poor's/Case-Shiller Home Price Index, the August 2009 price index in Detroit is at 71.59,which is the lowest of the 20 cities tracked and 22.6 percent lower than it was a year earlier.)

Holm and Radune plan to spray the house with water until it is gradually covered with ice. Come spring, after the ice has melted, the house will be demolished after crews salvage building materials.

Is this a cool concept or a cold-hearted gesture exploiting a recession-ravaged city? Leave a comment below.—Gian Trotta | e-mail | Twitter | Forums | Facebook

Essential information: Learn more about ice dams and how to prevent and deal with them. And check out our reports on roofing and siding.

Illustration courtesy of National Weather Service Weather Forecast Office.

Inside Consumer Reports Test Labs: Putting exterior siding through its paces

In years past, many homeowners decided against using vinyl siding for aesthetic reasons. One of the common knocks against this material had to do with the wavy, so-called oil-canning look that resulted from nails that were pounded in too tightly.

But with the waviness problem more or less eliminated—installers learned from their peers' mistakes, and many siding products are now more rigid—and thanks in part to its relatively low price and resistance to water and insects, vinyl now dominates the exterior-siding market.

Whether you use vinyl, plastic, or any other material, like those covered in our June 2009 report on siding and roofing, attractive siding can help boost the curb appeal of your home, important if you're selling your home.

"You have only one chance to make that first good impression," says Judy Moore, a regional vice president for the National Association of Realtors. "Exterior siding, roofing, the front door—all these things are crucial. The outside is a signal as to what the buyer can expect inside."

As you'll see in the video above, we tested both traditional vinyl siding and plastic shingles/shakes, which offer even more of a woodlike look with as little maintenance as vinyl. We also tested fiber-cement products, which cost about the same as vinyl and most resemble wood, even down to the need for periodical refinishing.

Our testers accelerated weathering tests to assess resistance to typical weathering cycles siding would encounter at your home, including heat, sunlight, and rain. They also measured how well the siding products withstood impacts in cold and warm temperatures. While the siding that scored the highest tended to be the thickest and priciest, we found exceptions. Our top picks in vinyl also included the Heartland Siding's HeartTech, which sells for a relatively low $75 per 100 square feet.—Ed Perratore | e-mail | Twitter | Forums | Facebook

Essential information: Siding and roofing are among the five home repairs you shouldn't ignore. Read our full report on these building products and check out the ratings of siding and roofing (available to subscribers) to find the best materials for your home.

Buzzword: Cool Roof

What it means. Never heard of a "cool roof"? Abandon your visions of an overhyped hipster-filled rooftop bar or eatery in an edgy, funky neighborhood. A cool roof, simply put, is a roof designed to reflect sunlight. Since the roof stays cooler, less heat is transferred to the building below, resulting in a cooler building and energy and money savings.

Why the buzz? U.S. Secretary of Energy Steven Chu recently made headlines when he was in London to attend a symposium on climate change. He said that painting all roofs white or light colors could help significantly reduce the amount of energy used to cool buildings.

But this idea is about not only the color of a roof but also its solar reflectance (SR) and thermal emittance (TE), which are rated on a scale of 0 to 1, with 1 being the most reflective or emissive. The Cool Roof Rating Council trade group says it rates products based on their initial values and after three years of weather exposure. The cool-roof concept is to use reflective coatings or materials. So a cool roof could be made of clay or concrete tiles or other materials suitable for a climate along with coatings in a range of colors that are designed to reflect the rays of the sun. The photo shows a home with MCA clay roof tiles in Riverside, California.

Cool roofs lower the surface temperature of a roof by up to 100*F, according to the California Energy Commission, which estimates that cool roofs can trim cooling costs by 20 percent on average in California. The CRRC estimates the average energy savings are 7 to 15 percent of cooling costs.

But the U.S. Department of Energy says that reflective roofs don't work in all situations, and the biggest benefits are reaped in hot, sunny climates where air conditioning is used frequently. Homes in shady spots or those with well-insulated attics might not see significant benefits. Cool roofs can also increase heating costs in the winter. To figure out how much energy you'll save, use the DOE's cool-roof calculator.

If you are considering a cool roof, find out whether the materials qualify for a federal tax credit and request a manufacturer's certification statement. You could receive a 30 percent tax credit (up to $1,500) for the material costs if the roof is installed this year or next. Also look online for rebates from utility companies.—Kimberly Janeway | e-mail | Twitter | Forums | Facebook

Essential information: Check out our June 2009 report on roofing and July 2009 report on air conditioning (available to subscribers), stay cool without sky-high energy bills, and read about ceiling fans.

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

Roofing and siding are home improvements you shouldn't ignore

You might be holding off on some "elective" home improvements during these tough economic times, but roofing and siding are among the five home repairs you shouldn't ignore.

In the June 2009 issue of Consumer Reports, our tests of dozens of roofing and siding products revealed 19 top picks that combine strength, style, and value. Two brands of roofing provided the more architecturally pleasing, layered look of dimensional shingles for a lower price than some flatter, three-tabbed shingles. And price was no guarantee of performance: One shingle that cost $340 per 100 square feet—five times the price of some of our top picks—ranked low in the ratings. For more on how price relates to performance, read our report on roofing and siding, which includes ratings of both products (report and ratings available to subscribers).

Some plastic siding panels molded to mimic wood shakes or shingles and fiber-cement clapboard looked even more like the real thing. One plastic siding that costs $315 per 100 square feet outscored two other pricier brands, and a brand that cost only $215 per square didn't resist fading well, but could be viable for well-shaded walls.

We found one fiber-cement siding product that cost only $70 per square but scored only fair for impact resistance.—Gian Trotta | e-mail | Twitter

Essential information: Read about five easy home spruce-ups you can do to boost curb appeal and find out which projects are best to do in the spring.