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Can You Roof Over Existing Shingles?

Roof shingle repair with Nile gun and hummer

Roofing projects require professionals who can handle the labour-intensive work while possessing knowledge of the city’s building guidelines and the proper roofing procedures. A good roofing contractor can advise you on the best options for your roof and get the job done. Count on Quinn Roofing Solutions for quality roofing and re-roofing services throughout Windsor and Southwestern Ontario.

Are you wondering if you can roof over existing shingles? The simple answer is that yes, you can. Given that, let’s discuss when re-roofing is a valid option. There are certain prerequisites for installing a new layer of shingles over an existing roof, such as:

  • The existing roof must be composed of asphalt shingles because re-roofing is a procedure restricted to asphalt shingles. It cannot be done with clay, wood or any other tiles.

  • The roof should be in good condition. Meaning, there should be no extensive damage to the shingles by way of warping. Shingles are made to be laid out flat, so any irregularities in the base on top of which they are supposed to be laid out will make proper installation impossible.

If a roof satisfies the above-mentioned requirements, it is eligible for re-roofing. The main reason why re-roofing is offered as an alternative to installing a new roof is that it is convenient and saves money by not requiring a tear-off. Also, if the existing roof is in good condition and the main concern is the look of the roof, re-roofing is the best choice. The old shingles will reinforce the roof and act as a failsafe if the new roof is damaged in the wind or rain. Most manufacturers don’t withdraw the warranties on their roofing products used for re-roofing projects as long as the work is done by a reliable roofing contractor. All of these factors make re-roofing an attractive option for homeowners. Re-roofing: Is It Always a Good Idea?

Re-roofing has its benefits but in the long run it can cause problems. Here are a few reasons why re-roofing is unfavourable:

  • It Compromises the Structural Integrity of the Roof Roofing structures are usually built keeping in mind the weight of a single layer of shingles and the weight of snow that might accumulate on it. Although shingles don’t look heavy, 100 square feet of good quality shingles weigh around 400 pounds. Adding a second layer of shingles on top of the existing roof would double the weight and cause the roofing structure to wear down a lot faster. Unless you are a hundred percent certain that the roofing structure is capable of handling the weight of a second layer of shingles, do not opt for re-roofing.

  • It Doesn’t Allow the Complete Revival of the Roof When a new layer of shingles is installed without tearing off the old layer, there is no way to replace the underlayment. No matter how many layers of shingles are there, water always finds a way through shingles. If there isn’t a proper layer of tar paper to stop the water, it can seep into the deck and cause damage. If the old roofing shows deterioration in the form of “sponginess” in certain areas during the inspection, it is best to tear off the old roof and replace the underlayment.

  • It Might Affect the Real Estate Value If you are planning to sell the house, re-roofing might seem like the perfect idea to give a new look to the house. However, home inspectors will report re-roofing and inform potential buyers about the drawbacks of purchasing such a house. As tearing down a double-layered roof costs more, buyers may back out of the deal.

Having read this blog, you may now have a good idea of how to approach your roofing project. However, consulting a roofing company before you choose between re-roofing and a tear-off will help you make the right choice. Quinn Roofing Solutions provides reliable roofing in Windsor and throughout Southwestern Ontario. Check out our previous roofing projects and see the work we are capable of. Contact us today for a free estimate on roofing services.


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