Green Roof Thermal Insulation

The thermal mass effect is the most important energy related benefit of a green roof.

Green roof thermal insulation.

In addition to thermal insulation a green roof also has a sound insulating effect. Department of energy polystyrene insulation comes in rigid foam boards that make it easy to insulate any part of a building. 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. The essence of the confusion lies in the difference between insulation and thermal mass.

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. In fact it s a form of plastic. 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. Quieter environment indoors and outdoors.

Polystyrene doesn t sound like a green material. The most common request i get from architects and engineers is for the r value of a green roof system. So you can also save on your heating bills in the winter. 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.

These all factors should include enhancing the thermal benefits from the green roofs. However a green roof with grasses or herbs contributes more to heat regulation because the substrate layer is thicker than for a sedum roof. 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.

Despite their rising popularity studies on green roofs thermal insulation performance are however limited. The r stands for resistance as in thermal resistance. 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. The term r value has a very specific meaning.

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 climate zones 10 12 and 13 with 1 sq. A compressive strength of 300 kpa declared in accordance with en 13164 is suitable for both green roofs and roof gardens. In the winter the heat regulating effect of a sedum roof is less than in the summer because a green roof retains moisture.

According to etag 031 xps insulation with a cs 10 y 300 designation i e. Of attic floor area and where at least 30 percent of the free ventilation area.