Pounds Per Square Foot For Green Roof

The additional weight of people on the roof must also be factored into the load calculations for a green roof.

Pounds per square foot for green roof. Semi intensive systems generally weigh between 25 and 40 pounds per square foot when dry. Before creating a new flat roof or having it rebuilt you need to calculate what your expected structural load is. You calculate this in pounds per square foot or usually abbreviated as psf. The foot or more of growing medium needed for an intensive green roof creates a load of 80 150 pounds 36 68 kilograms per square foot.

Semi intensive green roofs require a bit more maintenance since the plants tend to need pruning irrigation and fertilization. The ibhs also notes one inch of ice equals one foot of snow. Our green roof assemblies can be used in basic flat roof applications as well as more dynamic roof structures even on slopes up to 45 degrees. Today green roofs comes in two primary forms.

Xeroflor s green roof options include a range of lightweight systems from only 8 10 pounds per square foot to applications of 31 pounds per square foot. A built up roof for example will typically include the built up membrane itself with or without gravel as well as some kind of insulation and cover board which will vary in thickness from roof to roof. The fourth modular green roof system installed in 2008 was biotrays by green roof solutions. The dead load of a typical asphalt shingled wood framed roof is about 15 pounds per square foot.

The epa estimates that the cost of installing a green roof starts at around 10 per square foot for simpler extensive roofing and 25 per square foot for intensive roofs. The 800 square foot green paks system lies atop a root barrier and drainage mat and costs about 22 per square foot to furnish and install. Its dry weight is 12 pounds per square foot and its wet weight is 18 pounds per square foot. What is your expected structural load.

Note that roof systems typically include more than one type of material. The load increases with the use of heavier roofing material. They are typically constructed in layers but can also be installed using a tray system. Pounds per square foot lb ft 2 pounds per square 100 sq.

A more typical extensive roof with 3 to 4 inches of growing medium weighs 17 to 18 pounds per square foot and a deeper intensive system can weigh 35 pounds or more per square foot. Extensive green roofs are relatively light at 15 50 pounds 7 23 kilograms per square foot. Annual maintenance costs.