Can You Build a Roof Over an Existing Roof?


When you see that your roof is facing any issues or it is nearing its end, it is time you take matters into your hands and decide. You have to think about the roofing options that you have and what the best solution is. The best thing you can do is contact a professional roofer and talk to him in detail about the design, labor cost to add a roof over the patio, and other necessary details.

You might come across a situation where you might not have to remove the existing roof since it can still give service for more years to come, but there is an urgent need for better protection over the head; that is when you can go for reroofing and not roof replacement.

Can You Build a Roof Over an Existing One?

Can You Build a Roof Over an Existing One?

Yes, you can surely build a new roof over an existing one. When you see that your roof is failing but is still in good condition, you can choose to go for re-roofing, that is, getting a roof over an existing one. Your shingles might lose granules and are worn out due to age and weather, but it does not cause any leaks. So it is better to get a new shingle installed.

You can even go for reroofing if you want to get a new design, color, or aesthetic or if you have other preferences. Your existing roof will get some depth because of installing a new roof over another. Also, reroofing is much cheaper than a complete roof replacement. You won’t need labor to remove the whole roof and install a new one, making it easier and more cost-effective.

Roof Over an Existing One


Following are some advantages of getting a re-roofing done:

  • The cost of reroofing is much less than what you have to spend on a replacement.
  • Installing a new roof over an old one can be done faster.
  • When the re-roofing is done correctly, the overall appearance also gets elevated.
  • You get extra protection from rain, sun, and other weather conditions due to installing a new one over the old one.


Listed below are some disadvantages of getting a new roof installed over an old one:

  • By adding a new roof, the weight on your home’s structure will increase, which will require you to rethink the additional reinforcement.
  • A re-roofing has a shorter lifespan than a complete tear-off installation.
  • At times, when the reroofing is not done properly, it gives your house an uneven look.
  • Also, since reroofing includes only the installation of a new roof over an old one, you will not know what the issues are with your existing roof.

How to Add a Roof Over an Existing One?

How to Add a Roof Over an Existing One

Following are the steps involved in building a new roof over a new one:

  • Checking the Condition of Your Existing Roof: Before you start with the reroofing, you must inspect the condition of the existing roof.
  • Installing Drip Edge: A drip edge is a piece of metal extending almost 0.75 inches beyond your roof’s edge to check for runoff into your gutters.
  • Installing Starter Strips: The first row of shingles is known as a starter strip. You need to use those that are approximately 5 inches wide.
  • Flashing & Additional Rows of Shingles: Flashing needs to be installed correctly around elements that penetrate the roof and in the valleys where different roof parts meet.


The practice of roof-over offers several advantages, as discussed above. Thus, reroofing is a great idea if you don’t want to remove your existing roof. While a roof over is an effective solution, you should remember that it is unsuitable for every situation.

Proper planning, adherence to the local building codes, and professional expertise are advised for a successful project. Assessing the condition of the existing roof is essential before you determine what you want to do.

In short, whether you choose to build a new roof or not depends on what your home requires and what your expectations from the project.

Frequently Asked Questions

What Can Be the Probable Reasons for Building a Roof Over an Existing One?

You can build a roof over an existing one to increase energy efficiency, maximize the longevity of the existing roof, prevent leaks, and change the roof’s appearance.

Is It Necessary to Remove the Existing Roof Before Building a New Roof?

Well, it fully depends on the condition of the existing roof. There are instances when you can install a new roof solely because the existing one is in good condition, and the local building codes allow the same.

Are There Different Types of Roofing Materials Available for Building a Roof Over Another One?

Yes, you have many options when it comes to roofing material. Asphalt shingles, metal roofing, and green roofing systems are some of the options. The choice of the material depends upon your budget, climate, and aesthetic preferences.

How Much Does It Cost to Build a Roof Over an Existing One?

The pricing depends on various factors like the size of the roof, the kind of material you are using, and any structural modifications that you are doing. The best thing you can do is to get a quote from a reputed contractor.

Nicholas Hardy
With a Master’s degree in Civil Engineering from the University of Texas, Nicholas Hardy has dedicated over 12 years to roofing and building materials. She holds a Bachelor's degree in Architecture from Georgia Tech, where she has carved out a niche as a roofing expert with over a decade of experience. His insights have helped countless homeowners through renovation projects. His passion for design extends beyond work, as reflected in his engaging and informative articles. Outside work, she loves traveling and is an amazing photographer, capturing worldwide architectural marvels.

Why Is Disc Golf so Expensive?

Previous article

Can You Put Diesel in A Kerosene Heater

Next article

You may also like


Leave a reply

Your email address will not be published. Required fields are marked *

More in Roofing