By Jim Donovan

By Jim Donovan

PHILADELPHIA (CBS) — Have you finished up your spring cleaning yet?

Well, what about your roof? That’s right, in this week’s Angie’s List report, Jim Donovan explains roof cleaning and what you should know before you decide to do it.

Giving your roof a good cleaning is a great way to improve your home’s curb appeal.

“If you see algae or moss streaking on your roof, removing that can make your house look a lot better. But keep in mind, if your roof is old or in need of repair, that’s the first thing you should be doing before you step to cleaning it,” said Angie’s List founder, Angie Hicks.

And while cleaning a roof might not look like a difficult project, it’s not a good idea to tackle this on your own. It can be extremely dangerous.

“Let’s face it, you’re going to be on the roof, on a ladder, using water and detergent, which can make the roof very slippery. You should leave this project to a professional,” said Hicks.

The cost for having a roof cleaned typically ranges from $350 to $1,200 depending on the size, shape and pitch. But before you hire anyone, make sure you ask how they plan to clean it.

“When talking to potential companies about cleaning your roof, things you want to be careful of are anyone that considers pressure washing or abrasive detergents in order to clean the roof because they could potentially damage your roof or void your warranty,” said Hicks.

More from Angie:

Algae and moss growth:

• Asphalt shingle roofs that are in constant shade tend to attract algae growth, which feeds off of microscopic particles in the limestone used in the shingles.

• This growth can be seen as a black or dark green staining on the roof.

Whether the presence of the algae is detrimental to the roof’s lifespan is a debatable question.

Roof cleaning isn’t necessarily harmful if done professionally, and many homeowners value the aesthetics of a clean roof. But it pays to do your research and ask the right questions before you determine if roof cleaning is right for you.

Angie’s List Tips: Hiring a roof cleaner:

Cleaning method process: The contractor should explain in detail the equipment and the cleansers they use. Will the products damage your roof material, lawn or plants? Are their products environmentally safe? Steer clear of any company that insists on using high pressure washing or abrasive cleaners – both which can damage your roof and possibly void your roof’s warranty.

Ask about insurance: Any type of roof work is dangerous, and roof cleaning is no exception. Ask the contractor for proof of insurance/workers’ compensation before hiring.

Inquire about costs: Roof cleaning costs can range from $350-$1,200. The price depends on various factors including the size, shape, pitch, and infestation of the roof.

Is there a warranty? Ask the company about a warranty/guarantee? What steps will the company take if the algae/moss streaking reappears after a certain amount of time?

Ask for references: A reputable company will provide references of past clients and a portfolio of before/after work.

Don’t ignore repairs: If your roof is in need of repairs or replacement, it doesn’t make sense to invest in a cleaning. If you’re not sure, have a home inspector check out your roof before you do anything. Have your roof professionally inspected every two to three years.

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