Green Roof Structural Engineering

Modern green roofs typically use lightweight engineered soils with very light drainage and insulation layers.

Green roof structural engineering.

With regard to green roofs the overriding issue is one of structural capacity to accommodate the additional loads. Incorporating gardens or other forms of green roof plantings can be an attractive alternative to traditional building construction. The proposed depth of the system is 5. Waterproof membranes now make it easier to design green roof systems that capture water for irrigation allow drainage support the growing medium and resist the invasion of roots.

Some roofs are finished with substantial architectural build ups such as concrete pavers or stone. I have a client who is looking to place a green roof on top of a proposed single story commercial building. At sullivan engineering llc we define green roofs as those roofs that contain vegetation also known as vegetative roofs. The allowable depth of the green roof is determined by the load capacity that can be allocated to it.

Green roofs lessen the environmental extremes common on conventional roofs reduce storm water runoff increase energy efficiency and enhance the urban soundscape. Being the structural engineer i need to account for the weight imposed on the roof by the system. This chapter considers the technical and engineering considerations that stakeholders need to take into account. Practices that capture and store rainfall in an engineered growing media that is designed to support plant growth.

A portion of the captured rainfall evaporates or is taken up by plants which helps reduce runoff volumes peak runoff rates and pollutant loads on development sites. Proper selection of agriculturally durable materials structural engineering design and review and responsible water handling should all be considered to achieve maximum energy efficiency and perhaps leed recognition. Green roofing the term green roofs has taken on several different meanings in recent years. The first conservative assumption by structural engineers is to use the full saturated weight of 110 pcf for the full depth of the green roof assembly.

Removing unnecessary finishes may provide sufficient capacity for a green roof of equal weight. For retrofitting a green roof wall or facade it is important to establish early whether the installation will meet the existing structural capacity of the building or whether this will be modified to support the installation. Currently the building is being proposed using a modular roof system.