As green roof systems often come at higher installation cost, you want a waterproofing system that is providing the highest standards and gives you long term solutions. SOPREMA Alsan RS System is a quick curing, cold liquid-applied waterproofing two-part PMMA system that is low odor, VOC-complaint. As a seamless membrane, you will be provided with a monolithic membrane that has been proven to outlast any conventional waterproofing system that often fails on membrane overlap joints over a longer period of time. This system is fully reinforced with polyester fleece fabric, it also outperforms any sprayed or roller applied coating systems that are still offered with green roof applications. Fully adhered properties will provide you with less maintenance cost. This system will not allow moisture to travel between the waterproofing membrane and substrate while making it easier to detect and quickly repair if any damage should occur. Self-terminating properties will provide you aesthetic finish often eliminating costly counter-flashing and termination bar installation while adding clean finish lines to the green roof assembly. These systems are completely UV-light resistant, not requiring membrane surface protection from the weather as found with other systems. Also SOPREMA Alsan RS System can be installed at 23 F and still achieve quick curing within minutes. Applying the primer alone will provide temporary waterproofing up to six months giving the contractor better control over the project installation and planning. You have the waterproofing system installed, let's look at the green roof assembly choices and its maintenance budget cost: SOPREMA offers three basic "SopraNature" green roof assemblies to meet your building design criteria needs as well as your cost budget planning. Those systems will typically require a layer of polystyrene extruded board to increase thermal value (if required), a drainage/water retention mat, roof barrier (if required) as well as capillary mat that can provide you with unique properties that are not found with competitors products. This patented capillary mat, Aquamat Jardan has the highest retain age of water in the industry. This irrigation mat also acts as a root barrier. * Extensive Green Roof System: Four inches or less depth of engineered "Sopralite" growing medium soil (typical weight of 20 lbs/ft2 fully saturated + vegetation weight), this system will provide you with vegetation such as low-maintenance lawns, dry meadows, grasses, perennials and sedum (most commonly used). This system will require minimum maintenance cost (approx. $0.15 - 0.50/ft2 annually) and will withstand drought periods (up to several weeks depending on the selected vegetation type). * Semi-Intensive Green Roof System: Four to eight inches depth of engineered "Sopralite" growing medium soil (typical weight of 20-40 lbs/ft2 fully saturated + vegetation weight), this system will provide you with vegetation such as lawns, grasses, annuals, vegetable gardens, flower beds and perennials. This system will require medium maintenance cost (approx. $1-2/ft2 annually). * Intensive Green Roof System:Eight inches or more depth of engineered "Sopralite" growing medium soil (typical weight of 40 lbs/ft2 fully saturated + vegetation weight), this system will provide you with vegetation such as lawns, perennials, annuals, bushes and trees. This system will require a high maintenance cost (approx. $1-2/ft2 annually). Advantages/benefits you can expect from your green roof system: * Extension of the lifetime of the roof membrane system; green roof overburden assembly potentially extends the lifetime of the roof between 200-300% by protecting the roof surface from weather elements, large temperature fluctuations, drying wind and ultraviolet radiation. * Environmental benefits by reduction of heat island effect. Allow plants to produce oxygen providing your building tenants with cleaner air. New building construction will help you with LEED certification. Attract birds and butterflies as well as other species. * Noise reduction as green roof act as great acoustic insulators. Tests have shown that these roofs can reduce indoor sounds by as much as 40 decibels. * Water conservation and reduction of storm water runoff as the soil acts like a sponge and absorbs excess rain water. They contribute to reducing flooding and reduce impact of your building on the municipal storm drainage system. They also buffer the acid rain and remove nitrates and other contaminates. SOPREMA can transform your roof into an instant beautiful roof garden, expanding the usefulness of your building via patios, gardens and vistas taking out the design hassle from your hands. Contact your local SOPREMA representative for further details. Maciej Tobolewski is a SOPREMA Liquid Division representative, New York, N.Y.