A roof of any kind plays an important role in protecting your home and property from the different types of weather conditions and unwelcome guests like animals and insects. When the roof is in good order, many homeowners pay little mind to it, going about their daily tasks with little regard for this important home structure. However, there comes a time when the home’s roofing begins to show signs of wear and tear, requiring a bit of attention and even restoration.
In this blog, we will discuss all things related to flat roof recovery and renovation, filling you in on everything including when you need to consider roof recovery, when to restore the roof vs. replace it entirely, and the different types of restoration materials available.
Roof Recovery Systems Explained
A roof recovery system places a new membrane over an existing roof structure, extending its lifespan and improving its performance. If there is no structural damage to the roofing deck, these roof recovery systems can be installed over almost any roofing structure.
This method of roof restoration is far less labor and cost-intensive than replacing a roof, making it logical to consider. However, it’s not an option for significant structural damage and leaks.
Is My Roof a Candidate for Renovation/Recovery?
Not every roofing system is deemed “recovery” worthy by roofing contractors. A licensed professional must evaluate each tile or metal roof to see if a recovery system can potentially save it from a full replacement. Below are some of the necessary factors roofing contractors consider when determining whether to replace or renovate a roofing structure.
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 a further inspection. 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 important as it will develop mildew and other forms of costly damage.
Building Codes
It is also important to consider the building codes set by the state and region. Not all regions allow roof recovery, necessitating a roof replacement. For example, the International Building Code IBC excludes the following conditions from receiving re-cover systems:
- The existing roof 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 recovery installer.
Performance of Roofing Materials
If the roof has experienced leaks for some time, the insulation or deck under the membrane probably has some structural damage. Covering wet insulation or a deteriorated deck will only contribute to mildew growth.
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 Restoration 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.
Roofing Materials Used For Flat & Low-Slope Roofs
Choosing the material for your flat roof recovery is an important decision. After all, the new materials must bond well with the existing materials. 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 recovery.
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)
- Class 4 Hail Damage Rating & Puncture Resistance
- 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 that may lead to poor health outcomes
- Roofers can only install PVC on a clean, smooth surface which limits its use in roof recovers
Contact your Local Roofing Contractors!
Roof recovery and renovation services are far more affordable and require less labor than a whole re-roof project. If you know that your roof is decades old and you are considering having your roof replaced, allow the roofing contractor team from Legacy Roofing to assess the condition of your roof to see if it is a whole new roof or if we can save it with our renovation services. Get in touch with our team today to schedule your free estimate!
