Vegetative roof systems continue to be one of the most popular options for building owners who desire the addition of "sustainable" or "green" attributes for their buildings. Although vegetative roof systems can add many benefits, it is important they be designed and installed carefully to avoid sacrificing the weather-resistive properties all roof systems should provide.
In September, NRCA published The NRCA Vegetative Roof Systems Manual—Third Edition. The manual provides up-to-date NRCA best practices applicable to the design and installation of quality vegetative roof systems. The newest edition replaces The NRCA Vegetative Roof Systems Manual—Second Edition, published in 2009, and includes the following updates:
Revised waterproofing recommendations
As with the manual's second edition, NRCA recommends a protected-membrane configuration consisting of a built-in-place vegetative roof system with growth medium and plantings installed over an adhered waterproofing membrane; NRCA also provides information regarding extensive vegetative roof systems over conventional membrane roof systems.