What Is Re-Roofing?
Re-roofing is a way to completely add a new roof to your home without removing the old one. When re-roofing is employed, a second layer of shingles is placed on top of an existing roof. While not always possible, re-roofing can help you save on replacement costs. Since the existing roof does not need to be torn off, there’s less labor and time involved. The process is also called recovering, since the existing roof is covered with an extra layer.
Flat and low-pitched roofs usually consist of three layers.
- Weatherproofing: All roofs need at least one layer of weatherproofing to keep out moisture. Areas in colder regions might also need an ice-protective barrier.
- Reinforcement: Another layer adds durability, puncture-resistance and structural stability to the roof.
- Surfacing: A top layer protects the two bottom layers from the weather and sun. The surfacing can add additional benefits, such as fireproofing or energy-efficient solar reflective coatings.
A Residential pitched roof typically consists of four layers.
- Decking: Also called sheathing, this bottom layer of the roof is usually a panel of plywood that acts as a foundation for the roof.
- Ice and water barrier: Self-sealing and waterproof, the ice and water membrane protects your building from water penetration and ice build-up.
- Underlayment: A uniform layer of felt protects against water infiltration under the shingles and allows the shingles to lay flatter.
- Shingles: Asphalt shingles, metal panels or wood shakes are the recognizable outer layer of your roof. They provide architectural aesthetics as well as protection. Asphalt shingles will also have a fifth layer, called a ridge cap. The ridge cap is an extra-long shingle that fits over the vertices of the roof.
The factor that makes re-roofing cost-effective is that most of the layers of the roof stay intact. You do not invest in a whole new roof. Instead, you rely on its existing layers to give structure and protection for your building. Re-roofing offers significant cost savings since you are reusing these materials. It also keeps your building protected during the roof installation process, since these protective layers stay intact.
Since roofs have many layers, it is difficult to inspect them during the recovering process. If there’s any underlying damage to these layers, a re-roofing will not resolve the issue. Removing the shingles lets us install new materials. This process allows us to replace the other protective barriers of the roof. This ensures they will last for years to come.
When Is Re-Roofing a Good Idea?
There are many circumstances where re-roofing can be a cost-saving solution. A roof is an ideal candidate for re-roofing if it is nearing the end of its lifespan. It should still be in good shape. A roof under 15 years old with a minor issue in one area would gain more from a repair. This is a bigger savings rather than a total recovering.
If a roof is 15 years or older, it’s time to think about re-roofing. This is especially true if there are signs of wear or damage. If you find granules from asphalt shingles in the gutters, a new layer would be the perfect solution. A few minor leaks or issues can also be resolved with a recovering. The structural condition of your roof needs to be inspected before adding a new layer.
Before you can be certain re-roofing is a good idea, you should have an experienced roofer check it. A licensed roofing contractor will need to walk on the roof and inspect the construction. Even a seasoned professional can’t approve a re-roofing job from the ground. By peeling back some of the shingles, a professional can see if there are already two layers. The inspector will also walk around to check if the roof feels soft underfoot. They will also look for deterioration in the flashing.
Is your roof nearing the end of its life? You notice signs of wear in your commercial roof. Or, you know it is nearing the end of its warranty. Either way, you are wondering if it’s time for a replacement. If your roof is in good condition, you can re-roof the existing roof. This means you do not need to tear it off and install a new one. If your roof uses shingles, you can add a second layer of the material. Alternatively, if you use a protective industrial membrane, apply a second layer directly on top of the existing roof. You’ll add years to your roof’s life expectancy for a fraction of the cost of a full replacement.
What Is a Roof Replacement?
Recovering the existing roof is sometimes not possible. If a roof already has a second layer, you can’t add a third layer. The 2018 International Building Code (IBC) 1511.3.1.1 prohibits re-roofing when the existing roof has two or more applications of any roof covering. A roofer can’t re-cover a clay, slate, cement or asbestos-cement roof. Re-roofing is not possible when the current roof is water-soaked or has significant structural damage. If an inspection reveals the roof has compromised integrity, you should opt for a roof replacement instead.
Unlike re-roofing, a roof replacement tears out the existing roof and replaces it. The waterproofing and underlayment layers are removed and replaced with new material. Tearing out the shingles and underlayment lets roofers inspect the decking. If the decking is intact, new water barriers, underlayment and shingles are applied. If the decking has damage it will be repaired before the new roof is installed.
A roof replacement should be considered where a roof has more than a few small issues. Rather than covering up the damage, a new roof gives you structurally-sound, long-lasting handiwork. A new roof also comes with a warranty. Depending on the materials used, it will last between 10 and 50 years. A roof replacement gives you more materials choices when planning your re-roofing project.
A roof replacement is a significant investment. It costs more in labor, materials and time than re-roofing. With new materials, your building will have added protection and longer-lasting materials. You don’t have to question whether your roof is sound, because any issues are dealt with during replacement.
How Often Should You Replace Your Roof?
How many years your roof is designed to last depends on the type of roof you have. On an industrial flat roof, the roofing system protective layers you use can impact its lifespan. The materials used on a pitched roof will also have a different life expectancy. Weather damage, frequency of maintenance, slope and mistakes in installation can all influence how long your roof lasts.
Thermoplastic polyolefin (TPO): A type of single-ply roof membrane, TPO is popular for low-slope roofs. It’s a material known for high durability and extreme weather resistance. Protections from heat aging and UV degradation contribute even further to its longevity. The typical life expectancy is 22 to 30 years.
Ethylene Propylene Diene Monome (EPDM): An EPDM roofing system features a rubber membrane, which increases longevity. The rubber layer is durable and resistant to impacts, sun and heat damage. It can be installed over an existing roof, so it’s ideal for re-roofing. Rubber roofs are known to last between 22 and 35 years.
Polyvinyl chloride (PVC): Like TPO, a PVC roof is another type of single-ply white protective roofing layer. It’s an energy-efficient roofing choice since the color retains less heat. It’s also a fire-retardant material, known for its self-extinguishing abilities. PVC roofs can last between 20 and 30 years. Yet, their life expectancy should increase because of the added fire protective material.
Metal roofing systems or metal paneling: Metal roofs withstand water and air penetration. Metal roofs are easily retrofitted over an existing roof. They need little maintenance and can prolong the life of your roof. They can last between 30 and 45 years.
Asphalt roofing systems: Modified bitumen and built-up roofs both use asphalt as an adhesive. Slopped roofs often use asphalt shingles, which have a long lifespan with proper maintenance. An asphalt roof can last anywhere between 20 and 40 years.
A material’s projected lifespan is a critical factor in determining when it’s time for a replacement. There are lots of other signs. A roof that leaks in a few spots can be fixed with a roof recovering. Nevertheless, if there is significant damage, it is time to replace the roof.
Here are some signs of damage to look for:
Leaking or water damage
Missing shingles
Sagging in the roof deck
Visible holes
Dark spots
Mold, rot or moisture
Re-Roofing Versus Roof Replacement – What’s the Right Choice for You?
Deciding whether to re-roof or replace your roof starts with a roof inspection. You can choose to replace a roof by inspecting it from the ground. Still, you can’t make a safe decision to re-roof without examining the construction closely. When you have the roof replaced, all the material is torn off and inspected on-the-job. A decision about whether to replace the decking can be made after examining it first-hand. The inspection will need a roofing professional to walk on the roof and feel for structural damage.
Your first step when thinking about re-roofing is contact a professional roofing company.