This research aims to find out which waterproofing material is currently more in use in construction of flat roofs in Sarajevo, Bosnia and Herzegovina. By choosing interview method aim was to investigate what are the thinking’s of the Architects and Civil Engineers in case of waterproofing process and with which materials are they familiar. Therefore, discussion was based on answering the Research questions which are one of the main reasons why this paper is done. Waterproofing is a broad term, and it is different technical procedures to protect parts of an object or buildings that are temporarily or permanently subject to moisture and water, regardless of the source of moisture and water. The term waterproofing is commonly considered a protective measure of the buried parts of the object with the fact that in the construction of a flat roof on the object waterproofing has a very important role. It should be remembered that with good waterproofing, besides the basic structure, we protect the internal spaces from the water penetration, respectively moisture.

Keywords : Flat Roof, Membrane, Bitumen, Typology, Insulation, Foil, Waterproofing, Water, Synthetic.