Almost all roofs are sloped so that water falls off the edges. On the other hand, low-slope or flat roofs do not have anywhere for water to fall off. You may end up pooling water on your roof, eventually damaging your home.
Houses with low-slope or flat roofs especially need a roof membrane. This guide is all about roofing membranes in detail.
Roof membranes create continuous watertight coverings that protect the interiors of buildings. As a flat roofing system, membrane roofs are primarily used since they are watertight, essential when water isn’t shed immediately. In addition to being used on shallow pitched roofs, they are suitable for situations where shingles, slate, or tiles would not work.
Synthetic rubber, thermoplastics (PVC or similar materials), liquid polyurethane, or modified bitumen are materials used to construct membrane roofs. Weatherproofing components, reinforcement, and surfacing are the main components of a membrane roof. In some cases, a single material can perform multiple essential functions.
The substructure consists of wood, concrete, metal decking, insulation, plywood, underlays, vapor barriers, and other components below the main roofing layers.
Purpose of roofing membrane
Generally speaking, low slope roofs or roof facets are those with a pitch (aka steepness) less than 2:12 (less than two vertical units up for every 12 horizontal units out).
Low slope or flat roofs are less likely to run off as fast as higher pitched roofs because the water doesn’t run off as quickly.
Since asphalt shingles cannot sit in water, roofing codes and installation instructions prohibit their installation on roofs with pitches less than 2:12. The space below low sloped or flat roofs is therefore susceptible to leaks, which is why a membrane (or metal) roof system is required.
Types of roofing membrane
It is made from synthetic rubber and is called a thermoset membrane. During manufacturing, materials are heated and cured completely, which is why they are called thermoset membranes. As a result, the materials bind together tightly and maintain their shape.
EPDM (ethylene propylene diene monomer) is thermoset membranes’ most commonly used compound.
Fire resistance is a vital feature of Thermoset membranes. There is almost no risk of them burning. It is also a fact that these membranes are hazardous to both the environment and the people dealing with them.
EPDM Roof membrane
EPDM, or ethylene propylene diene monomer rubber, is the most common material in thermoset roofing. People generally refer to EPDM rubber roofs when they talk about rubber roofs.
Carbon black is usually used on these roofs to prevent UV degradation. A titanium dioxide finishes layer coats white EPDM roofs, preventing the heat island effect by reflecting the sun’s UV rays. However, this layer wears away over time.
There are two types of membranes available: reinforced and non-reinforced, with a thickness of 45 or 60 mils. Installing them can be done by adhering them, fastening them, or ballasting them. Priming and sealing seams with liquid adhesives or tapes are the first step in making a boat.
Because EPDM is made from petroleum-based chemicals, eco-friendly and healthy concerns are associated with its use. Yet, it remains a popular roofing material despite its environmental and health concerns.
Thermoplastic membranes can be reshaped using heat. Due to this, thermoplastic membranes have a more comprehensive range of applications than thermoset membranes.
A polyvinyl chloride membrane and a thermoplastic olefin membrane are most commonly used for these membranes.
In both cases, the membranes are white and reflect heat. As they keep rooms more relaxed, they are perfect for bedrooms or living rooms.
In roofing membranes, PVC is flexible and can be used in various ways. There is a good track record for its use on flat roofs since it has been around for much longer than TPO. Although it’s more expensive, it’s worth it.
The cost of TPO is lower than that of PVC. Although affordable, the first TPO membranes had poor quality due to manufacturers’ desire to keep them affordable. You don’t need to worry, though. Currently, its formulations are much better.
TPO is a suitable roofing membrane, but it hasn’t been around for long enough to determine its actual lifespan.
Multi-ply bitumen is the modern form of bitumen. To make a flat roof waterproof, you will need several layers.
Unlike thermosets and thermoplastics, however, thermosets and thermoplastics are one-ply membranes, respectively. They are more eco-friendly and use fewer materials, making them better suited to flat roofs. In addition to making them less hazardous to the environment, it also reduces the risk of injury to the people installing them.
Roof membrane by KEE
Ketone ethylene ester (KEE) is a roofing membrane material that is specifically designed to have superior chemical resistance and flexibility compared to other roofing materials. The KEE roofing membrane is made up of a thermoplastic compound of Ketone Ethylene Ester, making it extremely durable and resistant to weather conditions. The KEE roof membrane is also resistant to a wide range of chemicals, including acids, bases, oils, and greases. KEE roofing systems are commonly used in commercial and industrial roofing applications, where they provide excellent durability and long-term performance.
One of the benefits of the KEE roofing membrane is its flexibility. It can be easily installed in various shapes, sizes, and roofing systems and is highly resistant to punctures and other forms of damage. Additionally, it is available in a range of colors, making it an excellent option for buildings that require a specific aesthetic.
KEE roofing membranes are also designed to be low maintenance, requiring little to no upkeep over their lifespan. They are also energy-efficient, as they can be used to reflect sunlight and reduce the amount of heat absorbed by a building’s roof. With their exceptional durability, flexibility, and weather resistance, KEE roofing membranes are an excellent choice for a variety of commercial and industrial roofing applications.
A new type of roofing membrane developed to improve PVC roof technology has been called Ketone Ethylene Ester (KEE) since PVC degrades over time as its plasticizers evaporate. The formulation of some PVC roofs now includes KEE in small amounts. It must, however, exceed 50% of the polymer content by weight to be considered an actual KEE roof.
These sheets are usually white but can also come in other colors. They are available in thicknesses between 30 and 60 mils. In addition to being reinforced, KEE membranes are also hot air welded. Installing them adherently, mechanically fastening, or ballasting them is possible.
The modified bitumen
In the past, asphalt roofing was the most popular material for flat roofs. It was the best solution to prevent leaks from getting inside a building.
An asphalt and synthetic rubber mixture are called modified bitumen. Adding polyester fiber strengthens and increases the durability of the roof membrane.
The installation of these is simple. It is less common to use modified bitumen nowadays, however. It’s harmful to the environment. The people handling it are also at risk for health problems.
Roof Membrane SBS
The styrene-butadiene-styrene (SBS) membrane is usually more flexible (elastic) once it has been applied. Asphalt can be hot-mopped over the SBS membrane like it can be done with BUR membranes. In contrast, there are new peel-and-stick roofing products with adhesive backings.
These membranes, also called SBR membranes, are made of styrene-butadiene rubber.
Cost of roofing membrane
There are a few factors to consider to determine the cost of a membrane roof. There are multiple factors to consider, including the insulation underneath the membrane.
You’ll spend more if you use insulation thick enough to insulate an entire structure than if you’re gluing the membrane to fabric insulation. The size of the roof that will receive the membrane is another critical factor.
Generally, a small membrane roof should be budgeted between $14.00 and $17.00 per square foot, and a slightly larger roof should be budgeted between $12.00 and $15.00 per square foot. The cost per square foot decreases dramatically as you get into larger commercial projects.
Roofing Membrane Minimum Slope
There is no such thing as a perfectly flat roof because there still needs to be a watershed to the top drains. The slope of a low-slope roof is less than or equal to 3:12 in technical terms.
There are some owners or insurance companies who require flat roofs to have a minimum slope of 1/2 inch per foot instead of 1/4 inch per foot. Providing positive drainage to roof drains will prevent ponding water 48 hours after a heavy rainstorm. It is possible to achieve the slope by sloping the structural deck, using tapered insulation, or combining them both.
Ensure that the slope is designed to meet the roof manufacturer’s warranty requirements.
It is also recommended to consult the insurance company of the owner to ensure that their coverage requirements are met. Some insurers have more stringent wind speeds and roof uplift requirements. The FM Global Roof Deck Securement and Above-Deck Roof Components (1-29) Data Sheet is often referred to in architectural specifications for roofing design guidelines.
It is possible to find more economical solutions for steep sloped roofs.
FAQs (Frequently Asked Questions)
Which membrane is best for flat roofs?
There are several significant advantages to using EPDM as a flat roof membrane. It is a relatively low-cost material that offers quite a few benefits. Few membranes can compete with EPDM membranes’ simplicity of installation, strength, durability, and bright finish.
How does felt compare to fiberglass?
The durability and strength of fiberglass are much more excellent than those of felt. Because there are no seams, it’s less likely to fail and leak water, and if it’s damaged, a professional can repair it quickly. High performance, durability, and longevity are consumers’ benefits of fiberglass roofing.