Extensive Green Roof R Value

In other words go above r 20 and make green roof decisions for other reasons than energy.

Extensive green roof r value. Sailor et al jbp 2011. They provide shade to the top of a building evapotranspiration. Green roofs reduce the temperature of the building and the surrounding air in multiple ways. The plants in a green roof absorb water through their roots and then use surrounding heat from the air to evaporate the water while some roofs can reach temperatures of up to 90 f in the summertime these two features can allow.

The relation between u values and the substrate moisture was linear. The university of michigan performed a valuation study comparing a 2 000 square meter conventional roof and a green roof. A 2006 study by the university of michigan comparing costs of conventional and green roofs showed that on average installing a green roof costs about 22 00 sq. 8 to 20 per square foot.

Annual energy savings green roof soil depth 33 annual energy and energy cost savings per square meter of roof for green roofs on lodging l and office o buildings with three different soil depths 5 15 and 30 cm compared to a conventional roof. A green roof may improve property values and marketability especially in urban areas with little green space. We typically go. The study looked at a range of benefits of green roofs including stormwater management improved health benefits.

Highlights green roofs u value was experimentally determined on a paslink test cell. Green roofs save energy compared to uninsulated roofs or poorly insulated roofs or even better black poorly insulated roofs. Green roof with rock wool substrate provided the higher energy savings. The cooling effect of each green roof component was demonstrated.

Once you have more than r 20 in a roof assembly that is you meet the code things pretty much don t matter. In general the average r value of soil is 0 25 per inch so for a 12 soil depth the r value of the soil would be r 3 excluding assumptions on soil wetness and evapotranspiration. 15 to 50 per square foot.