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Can I Install a New Roof Over An Existing One?

can i go over my old roof during a roof replacement

If you are looking to replace your roof but don’t know if your roof can be repaired, we will gladly answer all your questions.

Although many believe it is better to have your entire roofing shingles removed and replaced from scratch. You can still have your roof installed on top of the old one. Many homeowners choose to do this, particularly if their old roof supports the structural integrity below. Before you make the decision to replace your roof, there are some important things that you need to consider.

Roof Replacement vs. Re-roofing – The Basics

Roof replacement is a laborious task that requires patience and hard work. This includes the entire reinstallation of your roof. The process begins with the removal of your old roof. The entire roof, including the deck, is removed and then the whole process of installing a new roof begins. It doesn’t matter how many layers of shingle you have on your roof, they all need to be torn off in order to begin the new roof installation. This requires additional labor and crew members in order to complete the job quickly.

A re-roof, or the installation of a roof over an existing roof, involves the addition of another shingle layer. If the roof is in good condition, it will not be leaking after a rainstorm. It could be at the end of its useful life or even losing its functionality. This is also called an overlay, which means that no tearing-off occurs. This process can be done more than once.

What are the pros and cons of a full roof replacement vs. roof repair?

When Is It Possible To Go Over Your Old Roof i.e Reroof?

Let’s take a look at some aspects that can make reroofing possible. These are just a few:

  • When your old roof is past its useful life.
  • Your shingles’ granules may have begun to wear away due to harsh weather, but they are not yet curled.
  • If there are no roof leaks, or other underlying problems.
  • If you want to give your home a fresh look without spending too much money. It is fast, efficient, and much less expensive than replacing a roof.

When Is It Not Feasible To Go Over Your Old Roof?

Here are some factors to consider:

  • If you don’t have asphalt shingles, reroofing may not be advisable. Because shingles can only be placed over old shingles.
  • If you have already got a reroof done over your old roof, then doing it the third time may make it unsafe to live in.
  • If there is extensive damage, then going over the old roof is often not recommended. It is better to go for a full roof replacement instead.
  • Curling shingles, trapped moisture. or prior bad roof install.


Going over your roof – The Pros and Cons

The following pros and cons can be used to help you narrow down your options for roof replacement.

The pros

  • It is cheaper than a new roof.
  • It requires less labor and takes less time than a roof replacement.
  • This quick fix will make your home look new again in no time.
  • Increases the lifespan of your roof by up to 15-20 years

The Cons

  • It is possible to overlook roof problems beneath.
  • It makes the roof heavier.
  • Two layers trap heat and retain it, making your home more hot and prematurely deteriorating the shingles.
  • If the top layer is not properly installed, it could lead to fungal and bacterial growth.
  • The actual cost to remove both layers and then have a new roof replaced

The Key Takeaway

If you are looking to get a roof replacement. It takes a lot of planning and calculation to make sure that a roof is replaced correctly. A professional roofing contractor is the best place to start since it has all the tools necessary to make sure your roof is replaced correctly.  Here are a few tips that will save you both time and money going forward.  If you are still considering a roof replacement compared to a repair, see our other helpful article below:

What Are the Pros and Cons of Doing a Full Roof Replacement Vs Roof Repair?