Can You Roof Over Asphalt Shingles? 

Created on:

January 16, 2023


Determining that it is time to remove your old roof and replace it with a new one is a big decision. But know that it is essential to your home's safety, protecting occupants and valuables from weather, pests, and other concerns. 

If you've waded into the waters of roof replacement, you've likely learned just how many factors there are to consider. When is the best time for a replacement? How much will it cost? These and other questions abound. It can leave you wondering if you really need to completely replace the roof by removing old shingles or if you can roof over them. 

If you're considering roofing over old asphalt shingles, wait to make your decision until you read our helpful guide below! 

Roof Over or Replace, What's the Difference? 

When it's time to replace your roof, you may be given the option to tear off the old shingles to lay new ones or apply new ones over the existing ones. Each type of replacement has a different process as well as advantages and disadvantages. 

Reroofing 

Roofing over existing shingles is often referred to as reroofing or an overlay. Instead of removing your old shingles and underlayment and taking your house down to the roof deck, roofers lay new shingles directly on top of your existing ones. Doing so means you will have more than one layer of shingles on your home. 

Reroofing can be offered as an option if your underlayment and roof deck are in stable condition; only the asphalt shingles are deteriorating. The deterioration should not go as far as resulting in leaks, but only loss of granules and strength, due to weather and age. Shingles should not be roofed over if they are missing, torn, or curling. Another occasion you may consider reroofing is when you want to change your look, opting for a new color or style when your existing shingles are not yet worn out. 

Reroofing does have advantages. It's often less expensive than a total replacement. A crew won't need to expend time and effort tearing off your old shingles and underlying structures, which makes for a shorter and cheaper job. Additionally, some homeowners like the three-dimensional look provided by more than one layer of shingles, though this 

shouldn't be a top priority. Finally, there is no shingle disposal to worry about, which can make it more eco-friendly. 

However, there are drawbacks. Roofing over your current layer of shingles means more weight on your roof. It adds pressure on your structural system that can take a toll over time. Your top layer may not always be flat or even, especially if the old shingles are warped or cupped. It may not look appealing to some. And last but not least is that overlaying doesn't allow a roofer to determine the condition of anything underneath the existing shingles. If your underlayment, flashing, or decking has issues, they won't be able to see it, which could cost you in the long run. 

Replacing Your Roof 

Roof replacement entails removing all the old shingles and underlayment. Your old curled, warped, or cracked shingles will be removed and disposed of. As will any that have grown moss or mold. Once your roof is down to the roof deck, or plywood, roofers can assess the structure's health. If you have any cracks, leaks, or areas of rot, they can address the situation. Afterward, they'll apply new underlayment, flashing, shingles, and other components to leave you with a brand-new, strong roof. Roof replacement is ideal if your roof has outlived its recommended lifespan, looks like it is deteriorating, or is causing concern due to age or wear and tear. 

The advantages of roof replacement are as you would imagine. It allows roofers to get a close inspection of the state of your home's structure and the roof deck. The contractor can fix any issues up front instead of hidden, which can prolong problems. All the old shingles are replaced with new ones, giving you another twelve to thirty years before you need to worry about replacement again. 

Of course, a total roof replacement is more expensive than an overlay. However, it can save most homeowners time and money upfront by revealing any structural issues and providing them with a safe and secure new roof that will last for years. Additionally, overlaying new shingles on top of old ones can sometimes void warranties and insurance policies, further exacerbating possible future costs. 

If you're considering refreshing your roof, ensure you get an inspection from a qualified team who can give an informed opinion on whether you're a candidate for replacement or reroofing. 

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