The unfortunate truth is that the benefits of maintaining a well-engineered roof system are easier to appreciate after something fails. Ideally, a correctly installed and well-maintained roof system will perform as required and keep the building dry. But replacement and repair can become costly when the roof system doesn’t perform as designed.
Most people don’t consider regular maintenance when their roof is functioning as expected. However, maintenance can’t come fast enough when the existing system reaches the end of its lifespan or is experiencing a leak.
It can’t be said enough—preventative maintenance is the best way to protect the longevity of your roof. Consider a roof recover if you’ve lapsed on your maintenance or inherited roof problems after buying a home or commercial building.
What is a Roof Recover?
A roof recovery system places a new membrane over an existing roof structure. Roofers can install these systems on roofs with damage, but only if the structural integrity of the roof deck is still sound.
A roof recover prolongs the life of an existing roof membrane for five to ten years but is different from a new roof system. Existing roof systems that are candidates for recovers have performed well to date and are approaching the end of their warranty periods.
Recovering a roof is far less labor and cost-intensive than replacing a roof, making it logical to consider. However, it’s not an option for significant leaks and damage. When evaluating an existing roof system to see if it is a good candidate for recovery, roofers review a list of items that include:
Drainage
If the roof’s existing drains and slopes provide appropriate water drainage, it might be a good candidate for recovery. If not, there’s no need for further review. If water remains on the roof for days in the form of puddles or seepage, you must replace the roof. Removing standing water from a flat or low-slope roof is imperative, or it will lead to costly damage.
Building Code
Consider if your state and city permit roof recovery under the prevailing code requirements. For example, the International Building Code (IBC excludes the following conditions from receiving re-cover systems:
- The existing roof/covering is water-soaked or has deteriorated so that it is not an adequate base for additional covering
- Where the existing roof covering is asbestos-cement tile, cement, clay, or slate
- The existing roof already has two or more covering applications
Existing Membrane
If a roof’s existing membrane seems a little dry, that’s fine. However, if it resembles a patched sail flapping in the wind, roof recovery will not work. An existing membrane is only under warranty for its own properties and adherence abilities. If an old roof membrane with a new cover flies off the roof, it is not the fault of the recover installer.
Performance
If the roof has experienced leaks for some time, the insulation or structural deck under the membrane is likely no longer sound. Covering wet insulation or a deteriorated deck will only cause the damage to worsen.
Roofers use thermal detection to discover how much of the roof insulation is contaminated and hopefully replace it. If there’s too much moisture or the roof’s performance is questionable, replacing the system is the best option.
Roof Recover vs. Replacement
What’s the difference between repair and replacement? Like most people, you might need clarification on roofing terms.
When fixing damage to an existing roof, the contractor decides to either remove old material or apply new material directly over the current layer. Most building codes define these options as:
- Roof Recover: Installation of a new roof covering over an existing covering without its removal
- Reroofing: Recovering or replacing an existing roof covering
- Roof Replacement: Removing the old roof covering, repairing damaged substrate, and installing a new covering
What’s the Difference Between a Flat and a Pitched Roof?
All roofing systems take abuse from natural elements and have to be maintained. Pitched, or sloped, roofs are fundamentally built to shed water and keep snow from piling up. They work similarly to fish scales in that their shingles, tiles, or shakes overlap to shed water.
Flat roofing systems are different. When appropriately installed, they have low slopes, often between 1/4” to 1/2” per foot. Flat roofs are sound systems when designed correctly, especially in warmer Arizona climates. However, their shallow slopes don’t shed water the same as pitched roofs.
What Recovers are Available for Flat / Low-Slope Roofs?
A prerequisite for all roof recovery options is the new material’s ability to bond to the existing substrate. Manufacturers have acceptable membrane options, but we highly recommend you choose a local contractor who has confirmed project-specific conditions and compatibility.
Choosing the material for your flat roof recover is an important decision. You want to be confident you’re making the best choice so that it doesn’t come back to bite you or your wallet later. Here are four of the best options for a flat roof recover.
Modified Bitumen
It didn’t take long for the public to stray from the built-up roofing (BUR) system’s traditional tar and gravel. In the early 1960s, manufacturers developed modified bitumen roofing (MBR) technology. MBR leveraged the conventional performance of flat roofs and added polymer-reinforced roof wear layers (cap sheets) for strength and durability.
Pros
- Consistent application (overlapping rolls create large, seamless areas)
- Cold-Resistant (polymer-reinforced layers give better elasticity and flexibility in colder temperatures)
- Inexpensive (compared to other systems)
- Fire Resistance (rated up to the highest fire rating: Class A)
Cons
- More safety considerations (some application techniques require an open flame)
- Must be installed by a professional contractor to prevent leaking
- Fire resistance level only lasts about 5-10 years
- Low life expectancy (lowest of roofing materials with a life span of about ten years)
EPDM Membrane
EPDM Ethylene propylene diene terpolymer (EPDM) is a black, synthetic/recycled rubber membrane commonly used in commercial, medical, and residential flat roofing. In addition to being environmentally friendly, it can bring down utility costs in cooler weather and comes in various textures and colors.
Pros
- Durable and lightweight (you don’t need to reinforce your roof deck)
- Easy Repairs (simple and inexpensive)
- Long-Lasting (up to 30 years)
- Waterproof (leaks are rare)
Cons
- Moderately expensive
- A professional roofing contractor with the appropriate flashing must install it
- Branches, storm damage, and foot traffic can damage it
- A professional roofer should inspect it every five years
TPO Membrane
Thermoplastic polyolefin (TPO) is a white, single-ply membrane used in commercial and residential roofing. Unlike EPDM, TPO’s light-colored white or gray membrane reflects heat instead of absorbing it, which can be ideal for summers in hot climates. However, it gets dirtier quicker than the darker EPDM option.
Pros
- Affordability (Property owners pay less than with other options)
- UV Resistant (surpasses the Environmental Protection Agency’s ENERGY STAR requirements)
- Energy-Saving (significantly reduces air conditioning cost)
- Easy maintenance (mold growth, punctures, and tears are virtually nonexistent)
Cons
- Lack of Research (product research is ongoing to determine lastability)
- Lamination (the uppermost part of TPO is laminated, which introduces weak points, shrinkage, and cracking in time)
- Quality Variations (manufacturers produce widely varying TPO quality and thickness)
- Seams (seams are present every six to eight feet and can loosen and lead to water leaks)
PVC Membrane
Like TPO, polyvinyl chloride (PVC) is a white, single-ply membrane used residentially and commercially. Aside from their chemical makeup, PVC shares similar characteristics and installation properties to TPO. The primary difference is that PVC is more flexible and backed by research. You can also expect approximately 20 years out of a PVC flat roof with proper installation.
Pros
- Cost (typically less expensive than TPO)
- Puncture Resistance (Class 4 hail damage rating allows it to withstand simulated 2-inch sized hail test)
- Heat-Welded (properly welded seams are more effective at keeping water out)
- Life Span (life expectancy of 20-30 years)
Cons
- No tolerance for cold climates (anything outside of -58° F to 347° F will damage it)
- Toxic chemicals (If burned, PVC releases dioxin, which damages reproductive, developmental, hormonal, and immune systems and can cause cancer)
- Roofers can only install PVC on a clean, smooth surface which limits its use in roof recovers
Contact your Local Roofer!
Reroofing requires a contractor to strip every part of the existing roof. They remove the insulation, membrane, and flashing until they reach the roof deck, which can be time-consuming and expensive. Because roof recovery systems use existing insulation and other roof materials, there is less to replace, making it more cost-effective and environmentally friendly.
Roof recovery systems are more affordable than a reroof, but they can still be costly. If a roof is already reaching the end of its life or has significant damage, getting a new roof that will last longer may be worth the extra money. Though this costs more up-front, it may save you money in the long run.
The best way to understand if your roof is best suited for recovery or replacement is to consult a local and reputable roofing company. Legacy Roofing has decades of experience in roof recoveries and replacements. To find out more, contact us today.
