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The Most Important Things to Know Before Replacing Your Shingle Roof

GAF Roof System
GAF Roof System

Posted on Friday, August 25, 2017
Categories: Hiring Home Improvement  |  Roofing & Siding

Replacing the shingles on your roof is one of the largest investments you can expect to make over the life of your home. In fact, according to Remodeling magazine’s 2016 Cost vs. Value Report, homeowners can expect to spend an average of $20,142 on a new roof. In return, the investment adds approximately $14,400 to the resale value of your home, or a 72 percent return on investment.

In order to protect your investment and ensure that you get the most longevity and premium performance from the new roof, there are important things for you to know before choosing new shingles and the contractor to install them.


If you need a new roof, and two layers of roofing are already in place, building codes require stripping the roofing down to the sheathing. Most homes are strong enough to support two layers of roofing, but installing some of the heavier laminated shingles over even a single layer may overstress rafters and other structural parts of your home.

A more important reason for complete removal before re-roofing is so that the roofer can check for rot, water damage, or insect infestation underneath and repair any damage prior to installing the new shingles. Your new shingles are only as good as the sheathing to which they are attached.


A proper roof is an integrated system including more than just the sheathing and the shingles.

  • Ice and water barrier is a rubberized, self-healing membrane that comes in 3’ high rolls and should be applied first, directly to the wood sheathing. Two rows are recommended along the eaves of the home to help prevent leaks due to water damming in your gutters, wind driven rain, and in the North, damaging ice dams. It should also be used in valleys and at eave and rake edges — the most leak-prone areas of the roof. Strongly recommended for chronic problem areas like skylights, dormers, vent pipes, chimneys, and other flashing areas

  • Roof deck underlay is next. In the past, felt paper was the most common option. Today there are many higher-tech options that prevent wind-driven rain or water from other sources from infiltrating under your shingles and causing damage to your roof structure or the inside of your home. These products also lay flatter than felt paper when installed and will not buckle. This helps reduce the risk of blow-off, by allowing your shingles to lay flatter and more uniformly.

  • Ventilation is critical! Proper attic ventilation systems allow a continual flow of outside air through the attic, protecting the efficiency of the insulation and helping to lower temperatures in the living space. It consists of a balance between air intake (at your eaves or soffits) and air exhaust (at or near your roof ridge). The U.S. FHA (Federal Housing Administration) recommends a minimum of at least 1 square foot of attic ventilation (both intake and exhaust) for every 300 square feet of attic space. For example, if your attic is 900 square feet, you need a total of 3 square feet of ventilation. This amount should be divided equally between intake and exhaust ventilation.


If you're considering going solar and also replacing your roof, it’s best to have both installed at the same time. Ideally, a structural engineer as well as a roofer should assess the roof’s condition, including how much weight it can handle. Before installing a rooftop solar system. Contact the roofing products’ manufacturer for written approval of the solar installation to ensure the roofing warranty will not be voided. Also, the fire classifications for the roof assembly and the solar system should be the same.


The quality of the shingles you use will have an impact on the durability of your roof. Consumers often look to Consumer Reports, which runs roofing tests measuring strength, impact and weathering of materials. High quality shingles with a lifetime warranty from reputable manufacturers like GAF (North America’s largest roofing manufacturer), are guaranteed to perform better over the life of your home and provide peace of mind.  Laminated shingles are more attractive than standard shingles. They have a thicker, more three-dimensional appearance, which makes them look more like slate or cedar than standard shingles, and last much longer.

Roof Replacement 


Every homeowner shopping for a new roof should look for proof of professional licensing, proof of workers’ compensation insurance specifically covering roofing contractors, and references from past customers. Your roofer should provide a copy of these documents with their proposal or estimate. It’s your responsibility to verify that the provided documents are valid and up-to-date.

In addition to getting quotes from at least three roofing companies (and not choosing the cheapest) before making a choice, you should also ask a prospective roofer to explain the installation process, in detail. When you’re making the final decision about which roofer to hire, factor in how well each explained and answered questions about installation. It gives you insight into how meticulous each company is.  After all, you are about to spend $20,000 on a new roof. It’s not unreasonable to know what you are getting.


In order for your new roof to last a lifetime, it must be installed properly. According to the insurance industry, the most common reason for a roof failing is improper installation. Even if a contractor installs the best shingle available, if it’s not installed correctly, the roof can fail. Common problems are improperly installed starter shingles, inadequate ventilation, skimping on important materials like sealants and leak barriers, and cutting corners with improper flashing.

Using a contractor who is experienced in installing a particular manufacturer’s product is important because they have experience with the products and know how things like the manufacturer’s roof deck protection, leak barriers, and ventilation all work together to help protect your home.

Tagged:installer, contractor, replacement, shingles, roofing

Add a Comment
That's a great point that a roof is more than just the shingles, it is also the underlay, water barrier, and ventilation. I have heard that ventilation can have a huge effect on the longevity of the roof, however, I'll make sure to pay more attention to the underlay next time we redo our roof. We live in a really cold climate so anything we can do to extend the life of the roof is worth it.
Posted by Kate Hansen on Saturday, September 16, 2017, 4:17 PM

My wife and I are going to need to replace our roof soon since it's so old, but we aren't sure where to start. I like that you suggest choosing a high-quality shingle material with a lifetime warranty. This would make me feel better knowing I won't have to replace it for a long time, so we'll definitely look into this more.
Posted by Derek Dewitt on Thursday, January 25, 2018, 11:03 AM

I just wanted to thank you for going over some considerations to think about when replacing a shingle roof. I actually didn't know that it could be good to choose a good roofer that has proof of a professional licensing. I wonder if it could be beneficial as well to maybe research the license they can earn so you understand more about how they work they put in to earn it.
Posted by Taylor Bishop on Tuesday, February 6, 2018, 8:21 AM

Thanks for the great post; it was helpful to read through these tips for choosing a roofing contractor for shingle repair, and I liked how you said to choose someone who has proof of professional licensing and worker's compensation. The shingles on my home are starting to curl up, so I'll be sure to keep this advice in mind when hiring someone to help fix this.
Posted by Jocelyn McDonald on Monday, July 2, 2018, 10:36 AM

I didn't know that a roof was more than just shingles. I thought that they acted as an ice and water barrier. Now knowing this information, I might want to call a professional roofer to do my roof replacement so that I can have it done right.
Posted by Dave Anderson on Friday, August 24, 2018, 7:48 PM
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