Green Roof Thermal Insulation

A compressive strength of 300 kpa declared in accordance with en 13164 is suitable for both green roofs and roof gardens.

Green roof thermal insulation.

Despite their rising popularity studies on green roofs thermal insulation performance are however limited. In climate zones 10 12 and 13 with 1 sq. However a green roof with grasses or herbs contributes more to heat regulation because the substrate layer is thicker than for a sedum roof. In fact it s a form of plastic.

Of attic floor area and where at least 30 percent of the free ventilation area. Department of energy polystyrene insulation comes in rigid foam boards that make it easy to insulate any part of a building. The term r value has a very specific meaning. In addition to thermal insulation a green roof also has a sound insulating effect.

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. Thermal insulation in some cases a green roof may include thermal insulation typically a layer of extruded polystyrene. So you can also save on your heating bills in the winter. However it cannot be used to assess eps insulation for green roofs due to the current limited history of use in green roofs and roof gardens.

Yet polystyrene is a fabulous insulator with r values that range from r 3 8 to r 4 4 per inch of thickness and so it s considered green because it helps save so much energy source. The r stands for resistance as in thermal resistance. The thermal mass effect is the most important energy related benefit of a green roof. These all factors should include enhancing the thermal benefits from the green roofs.

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. 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. According to etag 031 xps insulation with a cs 10 y 300 designation i e. In the winter the heat regulating effect of a sedum roof is less than in the summer because a green roof retains moisture.

The essence of the confusion lies in the difference between insulation and thermal mass. 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. Free ventilation area of attic ventilation for every 150 sq. The most common request i get from architects and engineers is for the r value of a green roof system.

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. 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.