An elastomeric roof coating is a liquid-applied waterproof membrane formulated to adhere to a clean substrate or existing roof covering, to renew, repair, or improve waterproofing and emissivity performance.

The elastic properties of an elastomeric roof coating allow it to expand and contract with the roof as temperatures change through the seasons. It is installed as a continuous, seamless, monolithic membrane without joints, overlaps, or other similar vulnerabilities.

Deck Flex Elastomeric Roof Coating for example also protects a roof from ultraviolet (UV) light and can lessen the effects of urban heat-island emissions.

What Elastomeric Coating Should I Use?

There are four main types of elastomeric coating, and each does a similar job, but one may be better than another in certain conditions.

Acrylic Coatings

Acrylic coatings are highly reflective, so are great for areas where UV protection is a key requirement. They durable and work well on roofs that have a slope and good drainage. However, acrylic isn’t the top choice for roofs with ponding issues.

Polyurethane Coatings

The pro-choice is a polyurethane coating for flat roof situations and areas that will be subject to higher than average levels of foot traffic. Ideal for use on commercial buildings and other areas where access to plant and equipment is required. Resists ponding well.

Silicone Coatings

Silicone based elastomeric coatings are the most hard wearing, and longest lasting of the products currently on the market. Their high solids content means that they achieve thickness levels easily and perform well in areas where UV protection is a major requirement.

SEBS Coatings

Synthetic rubberized coatings such as SEBS (Styrene Ethylbutlyene Styrene) are recommended for metal roofs. They often have a high VOC content so care should be taken during application and local regulations should be considered. However, SEBS coatings are resistant to acid and alkali spills and are very fast curing.

Where Can I Use an Elastomeric Roof Coating?

An elastomeric roof coating can be used over several different roof types. Its versatility makes it a great choice for metal, bitumen, or spray foam roofs. If your roof is nearing the end of its warranty an elastomeric roof covering can extend the life of your roof for another ten to twenty years.

What Tools Will I Need?

Elastomeric coating options can be applied in the same way that a paint product would be spread on a roof or deck. Use a four-inch brush to cut in around openings and edges and a roller on a long pole to spread the product out over larger areas.

Before you start work the area will need to be clean and dry, so be prepared with a stiff broom and a bucket as a minimum. Different roof types will require different levels of preparation, but as long as the surface is free of contaminants, stable, and not in need of repair then you are ready to go.

If you have already identified problem areas that may be letting by water, then these areas should be addressed before the main coating work begins. You can use elastomeric products to fill small repairs, pairing liquid coating with fibermesh for example.

For larger repairs, such as rotted out plyboard, or missing shingles, a more comprehensive repair will be required to ensure the whole roof is ready to take the new covering.

Metal Roof Application

Metal roofing is often used for steel-framed commercial buildings. It’s light, long-lasting, and resilient. However, it is also prone to rust and other damage over time. Using an elastomeric roof coating can help to extend the life of metal, and other roofs, by ten to twenty years.

Preparation is key to any successful coating application task. Ensuring the roof is free from rust, staining, paint flaking, or chalking, is essential. Any bare metal surfaces should be treated with a proprietary metal primer.

Whether a roof is powder-coated, painted, or galvanized should make no difference, as long as the surfaces are dust, damage, and contaminant-free. Clean the roof with a soapy water solution and make sure it is thoroughly dry before application.

Pro Tip:

On any low-pitch roof on which it is possible to walk it is a good idea to set up an adequate safety system to prevent tools, materials, and, most importantly, personnel, from falling off the edge of the roof.

Asphalt Roof Application

Asphalt-coated roofing materials such as bituminous shingles can be covered directly with an elastomeric roof coating. Use a stiff broom to remove any loose material and make sure all the shingles are securely adhered to the roof.

It is not a good idea to rely on the Deck Flex to secure the shingles, even so, it will penetrate any splits and fissures. For wider cracks that might be evident in valleys, or around service penetrations the coating should be backed up with a fiberglass layer as a robust detail.

Pro Tip:

Paint the top of cowlings or vent caps on a roof, but remember to tape over, and bag vents for HVAC, furnaces, and other services to prevent them from getting clogged.

Built-Up Roof Application

A built-up roof (BUR) is a multi-layer system with staggered joints to inhibit water ingress. As a flat roof system, it works well. Unfortunately, when there is a leak it is difficult to discover exactly where the fault lies as the water can track a long way between the layers.

Oftentimes the solution is to take the entire roof cover up and replace it. With an elastomeric system, this can usually be avoided. As long as the roof area has been properly remediated, i.e. all loose, broken, and damaged material has been made good, any residual problems can be overcome.

Pro Tip:

Apply your elastomeric roof coatings such as Deck Flex during the later morning and early afternoon periods to avoid times of high humidity.

Spray Foam Roof Application

Using polyurethane spray foam to seal and insulate a roof is a fairly new innovation in roofing, but it is incredibly good at making a low-slope roof watertight. It’s in this instance that an elastomeric roof coating excels as an emissivity inhibitor.

Not only will it protect the spray foam from UV degradation, but it will also reflect the sun’s rays and help to mitigate heat build-up inside the building.

Pro Tip:

On a rooftop, you are exposed to the sun. Wear a hat to protect your head and UV-resistant sunglasses to protect your eyes from glare.

Plywood Deck Flat Roof

Elastomeric roof coatings, as part of a roofing system, are perfect for all plywood deck flat roof projects. Use a built-up sandwich layer structure, starting with a stapled metal lath. Cover the lath completely with a thick coat of TetraCrete.

Roll out fiberglass mesh on top and cover with Deck Flex base coat. Then finish with a top coat for a durable, flexible roof that can withstand traffic and temperature extremes.

With a flashpoint of 240°F (115°C) its fire rating means that an elastomeric roof coating is the safe choice for plant platforms and enclosures.

Pro Tip:

When using staples to fix the steel mesh to the plyboard use 1nch by 5/8 staples at an average rate of at least 22 per square foot to ensure a good connection to the decking.

How Long Does an Elastomeric Roof Coating Last?

A properly applied elastomeric roofing system should be good for at least ten years and can often be guaranteed for up to twenty years.

Will an Elastomeric Roof Coating Stop Leaks?

One of the main benefits of using a silicone-based liquid-applied elastomeric roofing membrane is that it will settle into every fissure, any crack or hole no matter how small.

The larger, more obvious defects can be attended to with fiberglass patches. Smaller, almost invisible problems will be taken care of by the material adhering to the surface.

On a roof with valleys and multiple penetrations for vents and services there will be several opportunities for the regular expansion and contraction of the roof to pull apart and create gaps for water to enter a building.

When checking a roof for leaks the first places to look for damage and likely entryways will be these areas. If a flashing has failed around a vent, then wrapping it with fiberglass mesh and adhering it with an elastomeric solution will likely solve the issue.