Fall is prime time to put a new roof on your home. But before you spring into action, there are a few things you should know. Most importantly, buying new shingles without the rest of the roofing system is like buying a car with no engine.

“Even the highest-quality shingles cannot work to protect a home if one other part of your roofing system isn’t operating in perfect concert with the other parts,” says Bert Elliott, Owens Corning roofing systems expert.

So what is a roofing system, and how do you choose one that’s right for you? Here are a few tips:

First, know the signs that it’s time to replace your roof. Most likely your roof has asphalt shingles, as four out of five roofs in the United States do. Conduct a simple visual inspection from a ladder or by viewing the roof through binoculars. Signs that it might need replacing or repair include algae growth on the shingles, damaged flashing around chimneys and other openings, buckling, curling, blistering, missing shingles or rotten wood in the attic.

Next you’ll need to make sure that you understand what a roofing system is to know what to ask your contractor. It’s easy, if you think of your roof serving three important purposes: protection from the elements, ventilation and beautification.

* Ice and water barriers protect vulnerable areas such as eaves and valleys from ice, snow and driving rain.

* Underlayment products provide protection against water seepage between the shingles and the roof deck.

* Shingles protect your home from the elements while adding curb appeal as they can make up to 50 percent of the face of your home.

* Hip and ridge shingles add extra protection and style to a home’s roof ridge line.

* Gutter protection prevents clogs, while allowing water to flow freely.

*Ventilation products help ensure that your attic is properly ventilated, preventing mold growth.

* Attic insulation allows homes to become more energy efficient by maintaining a more comfortable temperature year round.

Ideally, all parts of your roofing system should come from a single manufacturer as it is designed to work together for maximum performance.

“While your contractor is up on the top of your home, ask him or her to make sure your attic is sufficiently insulated. A properly insulated attic helps increase the energy efficiency of your home and make your home more comfortable,” Elliott says. “The best part is it pays for itself over time in energy saved – a properly insulated home can help save up to 20 percent on heating and cooling bills and insulation is eligible for the tax credit too, according to the government’s Web site for the ENERGY STAR program.”

Once you understand the parts of a roofing system, consider how a roof can impact the curb appeal of a home. Work with your contractor to find a style and color that coordinates with the siding, colors, and style of your home.

Choosing a contractor to install your new roof is just as important as choosing the overall system itself. Use references from friends and family, and online resources like Owens Corning’s contractor locator – found at www.owenscorning.com – to gather names and information on candidates. Be sure to check contractors’ license status before you seek bids from them. And don’t automatically go for the lowest bid – be sure competing bids are comparing apples to apples before you decide on one.