John A. D’Annunzio
Fluid applied membrane systems have been available on the U.S. commercial waterproofing market for many years. The systems most frequently applied were hot- applied emulsions with or without reinforcements. The materials faced similar constraints as bitumen-based built-up roof systems for health and safety issues, particularly when used in tight, constrained areas, where a large portion of below grade waterproofing is required to be applied.
In the late 1990s, an asphaltic-rubber membrane system was developed that could be applied in cold-process fluid applied applications. The asphaltic-rubber material combines the elastic properties of rubber with the waterproof/weatherproof characteristics of a highly refined emulsified asphalt.
The resulting formulations are proprietary materials that form a properly adhered monolithic, seamless, asphaltic-rubber membrane. The resulting membrane can be applied to range from 20 mils to 200 mils dry. Unlike coatings that only provide a film surface or adhesives that require reinforcements for waterproofing capacity, the asphaltic-rubber forms to monolithic, seamless membrane that provides instant waterproofing/weatherproofing capabilities.
The asphaltic-rubber blend makes this product different for other variations of – what has been termed in the industry - as liquid rubber. The primary difference between asphaltic-rubber and liquid rubber is that liquid rubber uses low percentage of rubber polymers and compares more to the SEBS materials that were used in the 1990s. The higher percentage of rubber used in the asphaltic-rubber formulation provides the elasticity required for successful, long-term performance.
The asphaltic-rubber material is environmentally friendly and complies with LEED requirements. The benefit of the material formulation is that it uses natural materials. The materials two main components – asphalt and rubber – are produced from the ground. The product’s main attribute is that it successfully blends the waterproofing capabilities of emulsified asphalt with the flexibility and durability of rubber. The emulsified asphalt provides the waterproofing capacity of the material composition.
The asphalt used is a highly blended material that provides better physical characteristics than the low-cost thermoplastic formulations that are commonly used for adhesives and sealers. The emulsified asphalt is blended with a modified rubber to provide elasticity as asphalt in its singular form becomes brittle at 20-30 degrees F. The addition of the type of rubber and rubber content associated with this formulation eliminates the need for reinforcements that are required with all other asphalt blends.
The primary difference between the asphaltic-rubber materials and other ‘Liquid-Rubber’ materials is the rubber component – neoprene. Most other formulations consist of low cost thermoplastic formulations of water emulsion, solvent solutions and hot melts of asphalt. The asphaltic-rubber blend is more advanced and provides excellent physical property advantages. The choice of neoprene as the rubber component of this material is based on several physical property advantages that neoprene offers.
Neoprene is similar in physical properties to natural rubber, but it is stronger and has better aging and high temperature properties. Neoprene bonds are useful over a temperature range of -70 to 180 degrees F. Mechanically, neoprene bonds absorb vibration and display good shear and peel strength. Shear strengths on metal substrates can be as high as 3,000 to 5,000 psi. Cured neoprene films are more rigid than thermoplastic adhesives.
Neoprene deforms slightly under stress, which provides excellent fatigue and impact properties. In addition, neoprene has good resistance to water, salt spray, commonly encountered chemicals, and bio-deterioration. This makes the product well suited for all types of waterproofing construction.
Advantages of Asphaltic-Rubber Membranes
Asphaltic-rubber membranes combine the properties of adhesives and coatings while adding significant technological advancements that create an instant-setting waterproofing/weatherproofing membrane. It is the twenty-first century version of a built-up roof system that has the performance characteristics of modified bitumen and-because it is a monolithic, seamless membrane - it provides longer service life with less maintenance than single-ply systems. Asphaltic-rubber membranes provide economical solutions to all waterproofing/weatherproofing applications with superior performance characteristics.
Asphaltic-rubber membranes can be applied in all types of waterproofing, roofing, and exterior envelope conditions. The primary advantages of the material are as follows:
Superior elongation and recovery of 1,000+ percent or more: structures move and surfaces expand. Seasonal temperature changes alter the size and shape of every object. Asphaltic-rubber membranes have the capacity to stretch and recover, which allows for movement of the underlying surface. The material recovers to 90 percent of its original state after elongation.
Excellent adhesion: asphaltic- rubber bonds to most substrates and forms a permanent bond with itself resulting in self-healing and self-sealing properties. The asphaltic-rubber membrane provides excellent adhesion to metal, wood, plastic, and concrete - even ‘green’ concrete. It also provides strong adhesion to existing construction materials like built-up roofs, modified bitumen, thermosets and thermoplastic membranes, and all waterproofing materials. In most cases, no primer or tack coat is required. Sustainable and environmentally responsible: the materials contain no VOC’s and satisfy EPA regulations and environmental concerns. No special ventilation is required as the material is non-toxic, odorless, and non-flammable.
Safe applications: the material can be applied with trowels, squeegees or a specially designed dual-component spray rig. No heat, kettles, torches, or open flames are required in the application process. The material is safe to apply and possesses no health risks to the applicators.
Warranties: 10-25 year warranties are available.
Another primary advantage of the asphaltic- rubber membrane system is that the material is manufactured directly at application and it is self-leveling. This allows the membrane to conform to substrate irregularities and provides a continuous seal at penetrations, which are typically difficult details in waterproofing applications.
The instant, full adhesion of the membrane allows for continuous system application without additional components that would be required with other membrane applications. This eliminates the chances of deformation from the breakdown of different material system components. It also eliminates most of the application areas associated with multi-component systems. Deformations of one of the materials in the multi-components system can lead to failure of the total system.
Examples of typical defects in roofing/waterproofing systems are: loss of attachment from improper adhesive application at substrate, insulation or membrane; improperly aligned insulation; loss of attachment of insulation due to substrate irregularities; voids in membrane attachment that lead to blisters/ridges; and slumping or buckling flashings from improper attachment. Improper attachment of one component leads to differential movement in the system.
The elongation and flexibility of asphaltic- rubber membrane exceeds industry standards. The average elongation is over 1,000 percent and the material has the inherent ability to recover to 90 percent of its original form after elongation. This allows it to withstand typical thermal cycling and it performs in extreme cold/ heat conditions. Application temperatures are wider than most other adhesives and coatings and range from ambient outside temperatures of 20 degrees Fahrenheit to over 100 degrees Fahrenheit.
The membrane has natural UV resistant properties and can remain exposed for a short time span. Reflective coverings are recommended for long-term UV exposure. The membrane is compatible with all types of exterior paints and reflective coatings – without bleed through - if application is required. Granule surfacing can also be applied. The membrane is also very durable. Depending on applied dry mil thickness, the membrane can withstand heavy force and is puncture resistant with self-healing and self-sealing properties.
The membrane can be applied over damp surfaces and it can be exposed to ponded water in unlimited duration. The material has been used as pond liners and in containment tanks since its initial inception into the market. The water absorption rate is less than 1 percent, well below ASTM’s minimum water absorption rate of waterproofing materials, which is 5 percent.
Advantages of Asphaltic- Rubber Membrane for Applicators: No Equipment, No Reinforcements, No Seams
There are significant benefits to applicators of asphaltic-rubber membranes. The foremost benefit is the reduced crew size required for application. This is paramount due to the severe labor shortages affecting the construction industry.
In the September 23/October 3, 2016 edition of Engineering News Record there is a report that states the Associated General Contractors of America (AGC) has found two-thirds of construction firms are having difficulty filling construction trade positions. In the article, it is stated, “Shortages are the most severe in the Mid-west, where 77 percent of contractors’ report difficulties in hiring, followed by the South with 74 percent, the West with 71 percent, and the Northeast with 57 percent of contractors having trouble filling hourly positions.” Stephen Sandherr, CEO of AGC, recently told ENR, “Many firms have gone from worrying about not having enough work to not hiring enough workers.”
The primary application benefit of the asphaltic-rubber membranes is that the material can be applied with a brush and/or roller. This eliminates the need for expensive, specialized spray equipment. It also eliminates the down time associated with spray equipment, such as set-up, continual mixing of material (half-hour prior to use) and down time from equipment failure, hose clogging and cleaning.
The brush/roller application can be completed at any point of the building without set-up and at production rates comparable to spray applications. The material forms to a 60 mil (dry) membrane with one pass, cure time and full adhesion is obtained within minutes (depending on conditions) and there are no need for reinforcements at penetrations, flashings or terminations.
Adhesion to Concrete
The fluid applied asphaltic-rubber formulation was developed in the late 1990s. It was initially a response to hot-applied fluid applied membranes and was an advancement of the SEBS materials that were initially known as cold-process Built-up Roof Systems. The product’s main attribute is that it successfully blends the waterproofing capabilities of emulsified asphalt with the flexibility and durability of rubber.
The result of this combination is an instant set, seamless and monolithic membrane that provides true waterproofing protection immediately upon application. The product cures at a similar rate to hot-applied bitumen (asphalt or coal-tar). The rubber component serves as a binder to the emulsified asphalt and eliminates the need for further reinforcement from mesh, fabrics or felts that are required in all other cold fluid applied materials.
The asphaltic-rubber membrane provides two times (1500% +/-) the elongation rate of SEBS (coatings have no elongation capacity) and adhesion rate to concrete was recently tested at 800+ lbs. per square foot. (Note: The asphaltic-rubber membrane was recently tested under TAS 114 Appendix D for Miami Dade acceptance. The asphaltic-rubber membrane remained fully adhered throughout the test process as failure occurred at the test apparatus and not at the adhesion of the material to the concrete slab. There was no failure to the membrane.
Similar results occurred on a recent project in Puerto Rico when field adhesion tests were completed – the membrane remained fully adhered with no separation from the concrete surface.) Another primary advantage with the material is that it can be applied to ‘green’ concrete. This eliminates the typical 28-day wait period required for most waterproofing materials. It escalates the project timeline.
True Waterproofing Material
The asphaltic-rubber material forms to an impervious membrane that provides immediate waterproofing protection. The membrane is resistant to ponding water (indefinitely) and resists hydrostatic pressure as it passes a 150 psi hydrostatic head test, so the material can be applied in all waterproofing applications. The material demonstrates very low water absorption; ASTM E96 testing for water absorption rate is .028 grams. The material provides solutions to most waterproofing concerns. Typical waterproofing material and/or system failures occur from three primary issues; loss of adhesion, openings at seams, and openings at penetrations. These waterproofing failure points are eliminated by the use of the asphaltic rubber membrane:
Problem - Asphaltic-Rubber Membrane Solution
Loss of Adhesion - Concrete Adhesion of greater than 12 lb. /sq. ft.
Opening at Seams- -Monolithic – Seamless – Membrane
Openings at Penetrations - No Accessories Required (Differential Movement) 1000% + elongation & 90% Recovery
Uses of Asphaltic- Rubber Membranes
Because of the waterproofing/weatherproofing capacity, instant set cure, adhesion success with most substrates and materials, wide-range of application temperatures and membrane mil thickness that can range from 20 mils to 200 mils dry, asphaltic- rubber membranes can perform in most building exterior applications.
The materials application methods are also versatile and can be completed with varying ranges of equipment and skill level. The product can be applied with roller/brushes/squeegees, a single-component spray machine or a plural-component spray machine. The resulting physical properties of the material are identical no matter which application method is used. Therefore, the product can be applied by a range of experience levels: from novice homeowners on small projects up to the most advanced spray applicators on larger projects.
Asphaltic-rubber membrane systems are ideal for all waterproofing applications—above grade and below grade. In addition to the benefits of a monolithic, seamless membrane, asphaltic-rubber membranes possess the most important characteristics of a waterproofing membrane:
It is a fully functional membrane and waterproof within seconds of application Dry mil thickness can range from 20 mils to 200 mils,
Can withstand constant emersion to ponded water, Has water absorption rate of less than 1 percentIs resistant to a wide range of chemicals, soils and microorganisms, Corrosion resistant,
Excellent adhesion to concrete, Can be applied to ‘green concrete’, Fully adheres to wet surfaces, Has self-healing and self-sealing properties, Withstands thermal cycling.
Typical uses in above-grade and below-grade applications are:
Mud mats, Below grade foundations, Pond and/or fountain liners, Sea walls, Elevator pits, Plaza decks, Garden applications, Terraces, balconies, Planters, Vapor barriers, Above grade walls.
The asphaltic- rubber membranes have also been successfully applied in industrial tanks and containment tanks.
System warranties are available that range from 10 to 25 years.
How to Apply Asphaltic-Rubber Membranes: Waterproofing
The asphaltic-rubber membrane system is perfectly suited as a fluid-applied waterproofing system. The material’s excellent adhesion capabilities, high elongation properties and low water absorption rate are perfectly suited for all types of vertical and horizontal waterproofing applications. The system is ideal for plaza decks, balconies and terraces, planter boxes and all other waterproofing locations. Asphaltic-rubber membrane can be applied as a waterproofing system with all types of surfacing requirements: coatings, living plants and green assemblies, pavers, and poured concrete.
The asphaltic-rubber membrane system can be used on various substrates such as concrete, wood, and foam (ICF) to stop the infiltration of water into the structure. The system is normally used in below grade applications. It can be used in new construction, as well as on existing structures. The system is suitable for exterior and interior applications in all kinds of climates. The system may be enhanced by installing a water shield product between the rubber membrane and the dimple membrane, thus creating a waterproofing system that is virtually impenetrable. Preparation of the surface is extremely critical and must be completed in compliance with the manufacturers’ requirements.
All surfaces should be free from any loose material, oils, greases or other foreign material. Diesel fuel and mineral spirits should be removed from the surface. These should be removed prior to application by means recommended by the manufacturer. Power washing is oftentimes required. All cracks, penetrations, existing seams, transitions, and corners should be addressed by incorporating polyester fabric with the asphaltic- rubber in brush, roller or trowel grades.The ambient outside temperature for application should range from 20 degrees Fahrenheit to 100 degrees Fahrenheit. Consult the manufacturer for required provisions in both extreme heat and extreme cold conditions. In colder conditions, make certain that the material is stored in a warm climate prior to use. Do not allow the material to freeze. The material should be thoroughly mixed prior to application.
Once the preparation and proper repairs have been completed, the asphaltic-rubber membrane can be applied. Application can be completed with brush, roller or trowel or spray grade material can be applied using specialized equipment. Apply material in a full and even application. Install in strict accordance with manufacturer’s recommendations and approved submittals. Stir materials during application in accordance with manufacturer’s instructions to avoid product separation. Apply the material as a continuous, monolithic and seamless membrane of uniform thickness, beginning at the lowest point and terminating at the highest point. In the event the membrane is applied too thin, contact the manufacturer for recoat guidelines.
Prior to application, create a grid across the roof with spray paint, allocating one drum of material per section of the grid. Perform cut-outs to check mil thickness and retain samples. Three test cuts are to be taken per 1000 square-feet. In addition, continuously check wet millage by using the “T” post on a caliper mil gauge. After the asphaltic-rubber membrane has cured, repair any visible voids. Comply with manufacturer’s recommendations for proper membrane terminations.
For horizontal applications, apply the asphaltic-rubber membrane in a single, monolithic coat to minimum 80 mils wet/ 60 mils dry. Repair damaged installation in accordance with manufacturer’s requirements.
For vertical below-grade applications, apply the asphaltic-rubber membrane in a single, monolithic coat to minimum 100 mils wet/ 80 mils dry. Apply an approved Protection Board over the membrane prior to the backfill. The dimpled membrane drainage system is typically mechanically fastened in a user-friendly application method over the completed rubber membrane system. These materials are prefabricated and are available in various heights and lengths to suit the application.
After allowing the membrane to cure for 24 hours, install the dimpled membrane using dimpled membrane fasteners and membrane caps. Be sure to follow the recommended fastener pattern for the appropriate substrate. Backfill may take place immediately after the membrane application is complete. During the backfill, be sure to take precautions not to damage the waterproofing system.
John A. D’Annunzio Bio
John A. D’Annunzio has over thirty year’s-experience in roofing and waterproofing consulting and has completed projects for Schools and Universities, States and Municipalities, and Fortune 500 companies throughout the world. He is president of Paragon Roofing Technology, Inc. – a building exterior consulting and testing firm that he founded in 1991. Mr. D’Annunzio is experienced in all facets of roofing, waterproofing and building exterior consulting including forensics and evaluation of in-place roofing, waterproofing and exterior building systems on all types of structures, analyzing roofing for latent moisture using infrared thermography, nuclear, and capacitance thermalization, identifying and testing roofing materials on certified laboratory equipment in accordance with ASTM standards, development roofing/waterproofing restoration and roofing/waterproofing replacement project manuals and construction details, coordinating project bidding, administrating roofing and waterproofing contracts, facilitating progress meetings, monitoring roofing/waterproofing applications, participating in peer review of contract documents, shop drawings, CADD drawings, and submittals; and providing expert testimony in dispute resolution cases. Proficient in complete exterior building forensics. Projects have been completed throughout the United States, Canada, Mexico, South America and Europe.
Mr. D’Annunzio has written five books about roofing/waterproofing and is a technical details columnist for Roofing Contractor magazine and the Editorial Director of Building Envelope magazine. He has written over 100 published articles in construction trade magazines and has conducted extensive research in material technology, the results of which have been reported at numerous international and national symposiums and conferences. He has been a featured speaker at the International Roofing and Waterproofing Conference and the National Roofing Contractors Association Conference. Mr. D’Annunzio is accredited by AIA and frequently conducts seminars related to waterproofing technology.