Green roof system build-ups are not only installed on new buildings but also on refurbished buildings. The ecological advantages and benefits for urban development also apply to refurbished buildings. In some cases the Green Roof system build-up's thermal insulation values can be calculated as a certified value. The additional insulation is beneficial as it reduces the energy consumption and lowers the CO2 emissions.
Refurbished roofs are more or less older roofs, which were planned and designed during a time when the reduction of energy consumption and CO2 emissions were not an issue; however, the requirements for thermal insulation of buildings are now much higher. In the case that the old thermal insulation is still working and it is possible to install a root resistant waterproofing, a credited thermally insulating Green Roof system build-up can be installed and modern thermal insulation values achieved. There are Green Roof system build-ups, with certified thermal resistance values which have already become available over the last few years. These build-ups can reach an equivalence of 100mm of standard insulation.
A thermally insulating Extensive Green Roof system build-up can weigh as little as a gravel protection layer. If the load bearing capacity of the roof is high enough, an Intensive Green Roof system build-up is also possible on existing roofs. Even roofs with low perimeters can be greened when using a slotted angle profile. The profile is used to retain the Green Roof substrate and allow the build-up to be installed within the surrounding vegetation barrier and away from the perimeter.