Green roofs serve more than one purpose and generate numerous benefits for nature, buildings, and people. Partially or completely covered with vegetation and growing medium, when constructed, green roofs practically become part of nature, enhancing air quality, contributing to the absorption and filtration of rainwater, protecting buildings from UV rays, lowering temperatures in cities, creating new habitats for birds and insects and more. Moreover, buildings with green roofs also benefit from overall better energy efficiency, sustainability, and sound insulation. Finally, it goes without saying that green roofs create a number of opportunities for users in big cities by providing them with additional space for walks and recreation.
Unfortunately, these advantages are considered rather sparingly by the current Bulgarian legislation. Yet, this should in no way stop investors in large Bulgarian cities from envisaging the construction of green roofs for their buildings. This article reviews the existing Bulgarian legislation on green roofs.
Indicated solely by the term “roof gardens”, green roofs lack explicit legal definitions in the Bulgarian legislation. From the systematic interpretation of the provisions of Ordinance No РД-02-20-2 of 8.06.2016 for design, implementation, control and receiving of waterproofing systems on construction sites [1], it can be concluded that roof gardens are considered as usable flat roofs (i.e. roofs with a slope between 1.5 and 7%).
Pursuant to Article 38 of Ordinance No 7 of 22.12.2003 on the rules for the development of the separate types of territories and development zones [2], green areas can be built on the subterranean construction outside the outlines of buildings, as well as on top of them (i.e. on the roofs of buildings) for the purpose of providing the necessary percentage of green areas in regulated lots for residential, public or mixed use in “mixed central zone” territories.
The aforementioned exhausts the provisions concerning green roofs at the national level. Nevertheless, at the local level, the relevant Municipal Councils in large cities have the right to regulate specific rules for the green system on their territory by issuing Ordinances. Such Ordinances are adopted and currently valid for Sofia Municipality, Plovdiv Municipality, Varna Municipality, Burgas Municipality and Stara Zagora Municipality.
Sofia Municipality
In Article 25, para. 3 of the Ordinance for development, maintenance and protection of Sofia Municipality’s green system, it is accepted that green areas on terraces, roof gardens and above-ground buildings and facilities in development zones with building density of over 60%, are included in the total green area of a lot. The only condition for this is that a soil layer of more than 0.6 m is provided for in the lot’s structural design project and vertical planning project. In the case of a smaller soil layer (but not less than 0.3 m) the area of green zones is multiplied by a coefficient of 0.8. Such development zones are all falling into a group of central development zones within the meaning of Article 8, para. 1, item 1 of the Sofia Municipality Planning and Development Act [3].
Plovdiv Municipality
Pursuant to Article 20 of the Ordinance of the Municipality of Plovdiv for development, maintenance, and protection of its green system, the landscaping of roofs, terraces, facades, fences, and grass surfaced parking lots, does not make them green areas, and thus, they are not included in the total green area of lots, with the exception of the cases under Article 38 of Ordinance No 7 (cited above).
Varna Municipality
In Article 28, para. 3 of the Ordinance of the Municipality of Varna for development, management, control, and protection of its green system, it is indicated that the green areas on terraces, roof gardens and above-ground buildings and facilities are included in the total green area of a lot. The condition for this is that a soil layer of more than 0.60 m is provided for in its structural design project and vertical planning project. In the cases of a smaller soil layer (but not less than 0.30 m) the area of the respective green zone area is multiplied by a coefficient of 0.8.
Burgas Municipality
Article 9, para. 5 of the Ordinance for development and protection of the green system on the territory of the Municipality of Burgas stipulates that when it comes to regulated plots in residential development zones for medium and high construction, as well as to mixed central territories, green areas on terraces, roof gardens and above-ground buildings and facilities are included in the total green area of lots:
1. With a 1.0 coefficient and provided soil layer of more than 0.6 m;
2. With a 0.8 coefficient and provided soil layer between 0.3 and 0.6 m;
3. With a 0.4 coefficient and provided humus horizon of at least 0.1 m of special soil materials, guaranteeing the development of a plant layer (certified materials).
Stara Zagora Municipality
Finally, in accordance with Article 20, para. 1 of the Ordinance for development, maintenance and protection of the green system of the Municipality of Stara Zagora, green areas on terraces, roof gardens and above-ground construction are included in the total green area of lots with a coefficient of 1, if their structural design project and vertical planning project provide for a soil layer of 30 to 60 cm for planting shrub and grass vegetation and 80 cm thickness of the soil layer for planting trees.
Bottomline
This overview of the current legislation shows that green roofs in Bulgaria are being used solely as a relief in the context of the mandatory requirement to reach a minimum percentage of green areas when building on certain types of regulated lots. Essentially, this use is too insufficient bearing in mind the significant benefits that could be achieved with the introduction of detailed regulations containing clear rights and obligations in the field of green roofs, including more incentives for all investors in future buildings and for owners of already existing ones.
[1] Ordinance No РД-02-20-2 of 8.06.2016 for design, implementation, control and receiving of waterproofing systems on construction sites (promulgated, SG, issue 47, 21.06.2016, last amended and supplemented, SG, issue 59, 29.07.2016)
[2] Ordinance No 7 of 22.12.2003 on the rules for the development of the separate types of territories and development zones (promulgated, SG, issue 3, 13.01.2004, last amended and supplemented, issue 21, 1.03.2013)
[3] Sofia Municipality Planning and Development Act (promulgated, SG, issue 106, 27.12.2006, last amended and supplemented, issue 31, 10.04.2018)