Is it okay to install a new roof on top of an old one without removing the old shingles

Here at Rydel Roofing, we want to empower our clients with as much information as possible, so they can make smart decisions about their roofing and siding needs. While it may be tempting to install new shingles over old ones, it is never a good idea. Read on to learn why.

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  1. The existing shingle on your home is more than likely what is referred to as a three-tab shingle or organic shingle. These paper-based shingles coated with granules have done a great job of protecting your home from water, wind, hail, snow and everything mother nature could throw at them but they have also retained a certain degree of moisture. Additionally, there is a very high chance that moisture has accumulated beneath and between the shingles. If one were to install new shingles on top of these existing shingles, they would essentially be trapping this moisture in between the new shingles and the old ones creating a perfect environment for mould and bacterial growth. Over time, this will not only reduce the lifespan of the new shingles but also reduce the lifespan of the plywood supporting them.
  2. The second reason why it is a terrible idea to place new shingles on top of old shingles is that even if the old shingles look fine and flat, as time passes they will inevitably curl and warp in an upward direction. This warping will put upward pressure on the new shingles and create small gaps. As strong winds hit your shingles, these gaps will become susceptible to uplift and they will inevitably be pulled right off your roof.
  3. We believe in doing the job right the first time and that means completely removing all of the old roofing materials off your roof before installing new materials so we can inspect the plywood. If the plywood on your roof is mouldy, rotten or sagging, we will replace it and start with a fresh sheet. Here at Rydel, we will even replace up to 3 sheets of plywood free of charge!
  4. Every shingle manufacturer offers great warranties for their products. It has become the industry standard to offer at least a 25-year warranty against manufacturer defects and if a homeowner installs new shingles on top of old shingles, these warranties become null and void.
  5. The single most important reason why you should never install new roofing shingle on top of old shingles is that it is illegal and for good reason. In the event that your home catches fire, the fire department will need to be able to cut holes in your roof both to prevent backdraft and to give access to water. If a roof is covered with multiple layers of shingles, it becomes nearly impossible to cut these holes using an axe.

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The Smart Choice in Flat Roofing

For the past decade Rydel Roofing has been helping with flat roofing repairs, replacements and new installations. Our commitment to customers goes well beyond the leading tools, techniques, craftsmanship and standards we employ. From the moment you call us to when we shake hands on a completed project we are all about offering service at the highest level.

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Level 1

  • Professional inspections
  • Standardized checklist
  • Detailed documentation
  • Inspection of water stains & water damage
  • Exterior inspection for buckling, bubbling or rot.
  • Cleaning of drain baskets and gutters.
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Level 2

  • All from Level 1
  • Debris Removal
  • Small General Repairs Performed
  • Inspection Report for Larger Repairs
  • All Seams & Flashings of Roof Top Units Inspected
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Level 3

  • All from Level 2
  • All Visual Repairs Performed
  • Completed Roof Inspection Report with New Roof Cost
  • CAD Drawing of Roof
  • All Seams & Flashings on Roof Inspected
  • Infrared Roof Survey
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Our Team Goes Above and Beyond For Our Clients

Don’t Take Our Word For It

What People Said

I contacted Rydel Roofing to do a roof inspection. The entire experience has been very refreshing and professional. I had Shylo in the office ask all the right questions which helped me build so much confidence in the company.

– Kevin Khalaf

Trusted by the pros

The peace of mind that comes with ongoing maintenance

Learn more about how our ongoing maintenance program works. We take on the responsibility of inspecting your roof regularly, reporting our findings back, and working to extend the life of the roof.

The Benefits

Choose a company that has the ability to support your ongoing needs and has the right insurance and the best certifications.

Avoid needing early roof replacement.

A roof’s lifetime is shortened by 30% when no preventative maintenance is performed.

Cut Down Replacement Costs

Clients under our flat roof maintenance program receive a labour discount on any future work.

Comprehensive Roof Management

We take the responsibility of protecting your roof off of your hands allowing you to focus on other jobs that are important for the success of your business.

Our Commitment

We pledge to you, our customer, that you will be getting the best quality job at the fairest price available. We are a locally owned and operated Ottawa based company with skilled workers who take pride in every aspect of every job we complete. We are Fully Insured and all employees are fully covered by the Workplace Safety and Insurance Board (WSIB).

Emergency Repairs

We provide 24/7 Emergency Repair service for EPDM, BUR, TPO and SBS allowing you peace of mind to know that if anything should ever happen we have you covered to be there and minimize any damage.