Green Roof Thermal Insulation

Insulation with a thermal resistance of at least 0 85hr ft2 degree f btu or at least 3 4 inch air space is added to the roof deck over an attic or 7.

Green roof thermal insulation.

The r stands for resistance as in thermal resistance. Despite their rising popularity studies on green roofs thermal insulation performance are however limited. Green roofs temperatures have initially been found to be close to the air temperature and green roofs may also provide thermal insulation runoff reduction and carbon uptake but might require irrigation during dry periods. Department of energy polystyrene insulation comes in rigid foam boards that make it easy to insulate any part of a building.

In climate zones 10 12 and 13 with 1 sq. According to etag 031 xps insulation with a cs 10 y 300 designation i e. The essence of the confusion lies in the difference between insulation and thermal mass. So you can also save on your heating bills in the winter.

However a green roof with grasses or herbs contributes more to heat regulation because the substrate layer is thicker than for a sedum roof. The term r value has a very specific meaning. A compressive strength of 300 kpa declared in accordance with en 13164 is suitable for both green roofs and roof gardens. To save energy from green roofs depend on many factors such as the depth and composition of the substrate the climatic conditions plant type type of irrigation type of green roof and design insulation.

In the winter the heat regulating effect of a sedum roof is less than in the summer because a green roof retains moisture. The thermal mass effect is the most important energy related benefit of a green roof. In addition to thermal insulation a green roof also has a sound insulating effect. These all factors should include enhancing the thermal benefits from the green roofs.

Quieter environment indoors and outdoors. The basic anatomy of a green roof consists of vegetation growing medium filter membrane drainage layer waterproof root repellant layer roofing membrane support for plantings above thermal insulation vapor control layer and structural roof support. Thermal insulation in some cases a green roof may include thermal insulation typically a layer of extruded polystyrene. Free ventilation area of attic ventilation for every 150 sq.

Of attic floor area and where at least 30 percent of the free ventilation area. Unfortunately the ability of a green roof to control the flow of heat energy cannot and should not be described only by an r value not even an adjusted equivalent or approximate r value. Rather than keeping heat from migrating through the roof assembly the green roof acts as a heat sink that soaks up and retains thermal energy. While this can be positioned below the roof deck installation above the waterproofing known as an inverted green roof is preferred as it further protects the membrane from condensation and physical damage.

In fact it s a form of plastic. Polystyrene doesn t sound like a green material.