LEED™ in Sealants and Waterproofing
by: Michael Schmeida, LEED-Accredited Professional
Green building is the practice of designing and constructing occupied space that uses less energy, water, nonrenewable natural resources and allows for the convenient and continued use of methods by the building occupants.
Sealants and waterproofing have, even before green building became a trend, functioned in a “green” manner. Sealants have always been and by definition are used to seal gaps in the building envelope to eliminate the infiltration of air and water and thus one can deduce that these materials reduce the energy consumed to heat and/or cool the building. Today, however, green takes on a whole new meaning as it relates to traditional sealant and waterproofing applications and uses, as well as how these materials are made, and even which products are used.
The most notable guide for green building is the United States Green Building Council’s (USGBC) Leadership in Energy and Environmental Design (LEED) program. LEED is a systematic approach to building construction, design and use that makes the practice of green building easy to understand and achieve. LEED has evolved from one single program, LEED for New Construction and Major Renovations (known as LEED-NC), into many programs and even subprograms. Still, the most common LEED program in use today is LEED-NC.
Sustainable Site Credits:
The first section of LEED is the Sustainable Sites Credits. The overall spirit of this series of credits is to reduce the impact of construction as well as the existence of the building on the local ecosystem. By changing actions on the local level, the impact will be global.
Arguably the most noticeable effect on the local ecology, aside from the change to the landscape itself, is the resulting increase in what is called the heat island effect. The removal of natural landscape in place of concrete or blacktop results in an elevation in local temperature since these surfaces retain sunlight as heat. The easiest way to alleviate the heat island effect is to get rid of the concrete and asphalt. Of course, concrete is relatively inexpensive and very versatile as a building product. As such, just getting rid of it is not feasible. But, there are two waterproofing and coating remedies that alleviate this effect:
- Green roofs. These also have added benefits we will discuss later.
- White coatings on rooftops, parking areas, etc. A white coating must meet Energy Star™ requirements for reflectivity and emissivity. It also requires that such a coating be used over minimal percentages of the roof or parking surface, which vary depending on whether other anti-heat island effect techniques are utilized in design… most notably the installation of green roofs. In the case of all metal structures or those that are being rehabilitated with very low load-bearing capacity where green roofs are not an option, a white coating is the only feasible solution.
Green roofs and white coatings under the Sustainable Sites section are among a very few instances where simply by installing a product/system, building owners qualify for LEED points.
Figure 1: A Typical Green Roof. Green roofs have many ecological benefits including heat island reduction, storm water management and the plants convert carbon dioxide into oxygen.
Of course, this last statement implies that there are less obvious yet certainly viable opportunities within LEED for point contribution. One example under Sustainable Sites is a possible point for redeveloping a brownfield. Membranes tested to prevent infiltration by possible pollutants such as methane, petroleum distillates and even fuel make this possible. Another “soft” solution under the sustainable sites credits involves solutions for sealing the below-grade area in lagging applications. By utilizing lagging, a smaller excavation is required and subsequently a larger amount of property is undisturbed.
Water Efficiency Credits:
LEED addresses the need for preserving water resources. However, much as with brownfields and many more examples in LEED, there are not always direct opportunities for the sealant and weatherproofing industry, but indirect ones do exist. The same green roofs we mentioned before, when designed and planted for minimal watering, count towards Water Efficient Landscape calculations. As an example, if a building’s footprint were to cover 50% of the property and the entire roof was a low or even zero water-consuming green roof, then 50% of the landscape would contribute towards this credit.
Another more abstract impact on the industry is in the collection of water for use in non-potable situations such as flushing of toilets and landscape watering. Pre-manufactured drainage is an ideal tool for gathering run-off to be subsequently transported and stored in cisterns, retention ponds, etc. for such uses and thus helps to meet the other two credits in this section -- Water Use Reduction and Innovative Wastewater Technologies. Additionally, roof coatings that are approved for the catchment of potable water by a government agency (e.g. National Science Foundation) are ideal for collecting rainwater for human consumption. These coatings in white also have the added heat island reduction aspect previously discussed.
Figure 2: A Prefabricated Drainage Media. Such media can be used to collect rainwater which can subsequently be used in the place of potable water for watering plants, flushing toilets and other non-potable applications.
Energy and Atmosphere Credits:
Despite your personal beliefs about climate change, no one can argue we are in the midst of a major energy crisis. This crisis is one which the construction industry is forced to deal with as 40 percent of all energy resources are for lighting, HVAC and maintaining buildings. Relating back to LEED, approximately 25 percent of the points needed for certification can be obtained under one credit of Energy and Atmosphere -- the Optimized Energy Performance credit.
Products in the sealant and weatherproofing industry can assist in building green by helping to minimize energy consumption in many ways:
- Using sealants to seal all gaps in duct work and insulating products in all fenestration openings and around HVAC units, conduits, etc. eliminates the leakage and energy loss of HVAC.
- Using air barrier systems on the above-grade building envelope to eliminate the transfer of air between the inside and the outside of the envelope. Studies by the U.S. Department of Energy have shown the reduction of HVAC can be as much as 40 percent.
- Alternative roofing solutions. Through the use of high reflectivity/low emissivity white roofing, heat buildup is avoided and demand on HVAC is reduced. Green roofs are also less heat absorptive than conventional roofing.
- Alternatives to conventional drainage such as prefabricated drainage for below-grade that also functions as an insulating layer.
Figure 3: Spray Application of an Air Barrier Membrane. In combination with sealants and flashings, a complete air barrier system can eliminate air loss in the building façade, reducing HVAC use by up to 40 percent.
Reduced energy consumption is not the only credit which those in the sealants industry should find important. Manufacturers of aerosolized products, particularly aerosolized foams, not only are providing a product that is insulating and gap-filling, but also are utilizing next-generation propellants that are free of ozone-depleting chemicals which helps their customers attain points under the Ozone Depletion Credit. Finally, the sum of our efforts in reducing energy consumption combined with other methods such as on-site solar panels help in attaining Green Power Credits by allowing building owners to not only rely less on power from the grid, but in the case of those with production capabilities exceeding consumption, place energy onto the grid for others.
Materials and Resources:
A third major ecological issue is materials. When it comes to sealants and waterproofing, one is most concerned about the source, disposal and transport of materials.
Construction waste management, or disposal, is by far the most visible of the three areas. Diverting as much waste as possible from the landfill is being emphasized here. Packages such as plastic tubes, cans, aluminum foils and buckets/pails are generally recyclable. Drums, totes and even tankers are considered in most cases to be recyclable/reusable. Another benefit in some cases is these containers can be sold for scrap. Even if the packaging cannot be diverted from the landfill, packaging such as foil wrapping which is completely crushed reduces the volume of landfill-bound waste.
Similarly, LEED places emphasis on the recycled content of materials used in the construction process. Historically, many of the products used in sealing the building envelope utilize virgin materials. Though most products may not have any recycled content, LEED acknowledges the recycled content in the packaging itself as well as cases/boxes and pallets.
As sealants and weatherproofing generally account for less than 2 percent of the total construction costs of the job, even products with minimal recycled content, which are the vast number of the products in the sealants field, have an overall minimal negative impact on the average for the entire job. Though some sheet-applied membranes and most prefabricated drainage media have a much higher recycled content, the impact is still quite small.
The third point category within Materials and Resources that affects the sealants and waterproofing industry is Regional Materials. These are defined as:
- Locally manufactured materials have final assembly/manufacturing within 500 straight-line miles of the job site.
- Locally harvested materials are those that are harvested (harvested meaning grown, mined, or similarly “picked”) within 500 straight-line miles of the job site.
If a job is within 500 miles of the plant, that means you are making a positive contribution towards obtaining the locally manufactured point. If you are not so lucky, though, it is not, nor should it be, a make or break issue as again the point is calculated based on dollar value of the material and this is a small part of the finished building. The same can be said for the locally harvested portion of this credit. This point has a bigger twist, though, as most, if not all, manufacturers have several suppliers for each raw material. In turn, each of these suppliers likely has more than one source for its raw materials and so on. Consequently, we have very little chance of knowing which point source raw materials originated from for any given production run.
The final credit area of concern in this section is the use of Rapidly Renewable Materials. Many of our products have a basis in petroleum-based chemicals, which are becoming scarce. Fortunately, we are just now getting to a point where plant-based raw materials are of high enough quality to begin moving away from petroleum-based raw materials.
Indoor Environmental Quality:
Another aspect of LEED, besides the concerns over environmental impact, is the emphasis placed on providing a pleasant and healthy environment for building occupants and construction workers. Employees are the single largest dollar investment for any organization and providing an environment in which they can be more productive ensures a good return on investment.
First, VOC content is directly addressed in LEED via the Low-Emitting Materials Credit. There are two basic requirements for VOC content outlined in LEED:
- SCAQMD Rule 1168.
- BAAQMD Regulation 8, Rule 51.
The emphasis on Daylight and Outdoor Views is another area in Indoor Environmental Quality that is specifically designed for occupant comfort. The premise is that by eliminating spaces of fluorescent lights and no windows, occupants will feel better emotionally. In addition, by allowing natural light in to illuminate space, electricity is saved. The use of more windows means better glazing and curtainwall solutions must be provided to minimize HVAC consumption. Regarding HVAC, Ventilation Effectiveness is also taken into account. Again, sealants have always been used to maximize HVAC efficiency.
LEED also places emphasis on Indoor Chemical and Pollutant Source Control. The intent is to keep the necessary evils of occupying a structure (janitorial closets, restrooms, etc.) from contaminating office and/or living space. Even products not considered as typical sealants, such as firestopping sealants, work to insure indoor environmental quality.
Figure 4: A Firestopping Sealant at a Through-Wall Penetration. While the primary focus of the sealant is to prevent fire and smoke migration, it has the secondary function of preventing everyday air flow, isolating possible pollutants and irritants.
Innovation and Design Process:
Finally, LEED has what can best be described as a “free answer” section. There are two credits in this section:
- Innovation in Design. This is awarded if the USGBC determines a project has in some way gone above and beyond what was required for some aspect of LEED.
- LEED AP. This is awarded if a member of the project team holds the LEED AP title.
Ultimately, our society must deal with the environment in which we are a part. Given that building construction and occupancy has a significant impact on the environment, it is only logical that ecologically friendly building design and construction practices can significantly help to improve our environment. LEED in particular has made it easier to understand and accomplish such construction practices and thus has led to broader acceptance. As sealant and weatherproofing professionals, embracing this change and adapting ourselves to it not only makes sound business sense, but common sense as well.