R Value Of Green Roof

R value of various materials.

R value of green roof. Here s a handy r value table that covers most types of roof coverings building insulation and a few other materials. Green roofs can have lower energy cost than conventional roofs and sometimes compete well against white roofing effects are more pronounced for lodging buildings. At 40 pounds each the trays are heavy and meant to be installed by a certified contractor. Insulation level are specified by r value.

Every construction design architect engineer a e knows a material s r value is an important factor when specifying insulation products with many regulations requiring minimum values for wall ceiling and roof assemblies. For example a code may require that skylights have only an r 5. R value of about 2 5 ft f btu. 1982 wong et al.

Recommended home insulation r values. Determining insulation r value accuracy. Increased r value a measure of the resistance of a material to heat flow of the roofing system along with reduced temperatures on the roof lessen hvac loads resulting in energy cost savings. Green roofs reduce the temperature of the building and the surrounding air in multiple ways.

These r values are a sum meaning this should be the total r value once you add up the entire depth of insulation. Traditional roof green roof n sensible et r q q q substrate 0 where r n net radiation q sensible sensible heat flux due to convection q et. A green roof may improve property values and marketability especially in urban areas with little green space. R s landscaping did the job here.

Hardy sedums are most popular for green roofs because they thrive in a soilless growing medium and are drought tolerant. 2003 evapotranspiration schmidt 2003 berghage et al. 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. Skylights and roof hatches are another component of roof thermal performance.

They provide shade to the top of a building evapotranspiration. Let s imagine a roof that should have an r 30 value. Neglected thermal storage moisture dependent performance and. See how this roof went from bare to bountiful plus the latest on living roof diy options.

You should of course see the manufacturer provided technical data sheet for the r value of specific products. For a very good introductory overview article on r value see r values over at the website of. For example if you have a type of insulation that has an r value of r 5 per inch of thickness you will need a depth of 6 inches of this insulation installed in your attic to reach r 30 if you live in zones 2 or 3. R value is a measure of insulation s ability to resist heat traveling through it.