There are many reasons why installing a new roof is better than simply mixing old shingles with new ones. Some DIYers think that they can save money by putting a new shingle over the old one, creating a layover sandwich that will never really look good on their roof. While this may seem very economical and convenient in the short term, it may have some serious consequences in the long run. Here are 5 reasons why you should never mix old and new shingle when reroofing.

  1. It can reduce if not void the warranty of your new roof. 

Whenever you add new shingles to your existing roof, you will also need to add insulating layers. Unfortunately, this traps heat in between the old and new layers of shingles which can significantly affect the lifespan of your roof. Typically, excessive heat will curl shingles, losing their structural integrity in the process. Many manufacturers do not want to provide a warranty for such types of roofs. Furthermore, adding a new dimensional shingle over an old one will create a less than perfect seal for the new shingle because of the unevenness of the surface.

  1. It prevents efficient inspection of roof integrity. 

Layover roofing will not allow efficient inspection of your roof’s overall integrity. While you may think that leaks are often visible from the inside of your home, there will always be issues on the roof itself that need to be carefully inspected. Layover roofing will simply not allow a closer inspection of the roof shingles for signs of rot or damage. Having a new roof will address this issue as well as provide a more effective means of tracking leaks through the shingles.

  1. Underlayment cannot be fully upgraded. 

If you put a new shingle over an old one, you will also have to install a new ice guard, new flashing assembly, or even a new eave metal. Unfortunately, you cannot install these pieces of new hardware without removing the old roof. If you try to install the new structure you must over the old shingle as well. This can be catastrophic in the long run. A new roof is always a better solution.

  1. It can be costly in the long run. 

Buying cheap new shingles and putting them on top of your existing shingles may seem economical. However, remember that you are essentially covering older shingles that will age a lot faster because of the stress placed on it. Give it a few more years and you will have to tear all these apart simply because the top layer no longer supported by the bottom layer. Getting a new roof now is simply more economical and safer than the alternative.

  1. It puts a strain on the roof frame. 

Overlaying can put a significant strain on your roof frame. This is because of the added weight of the shingles and other underlayment installed over existing hardware. For an older house, this can be a major problem.

Don’t think you’re going to save money by overlaying your old shingles with new ones. It is always better to get a new roof if you want to maintain the integrity of your house.