Roof terraces: pathology of water tightness

It's a fact that flat roofs seem to have been a problem from the outset. Leakage from roof terraces is a recurrent pathology in the world of construction, and particularly in that of waterproofing.

Yet this type of roofing has been in vogue for over a century. Its success is due in particular to the development of reinforced concrete and the renewal of architectural style in the early and mid-20th century.

It has to be said that flat roofs are particularly attractive because of their low investment cost. All you have to do is waterproof and protect the top floor. There's no need for framing, tiles or other roofing materials. What's more, the building can be raised by one or two storeys at no extra cost, subject to structural verification. Last but not least, waterproofing is relatively easy to carry out, and therefore less costly than replacing the traditional roof.

Despite the many well-known pathologies, and the setbacks experienced by occupants and managers, these economic advantages have largely encouraged the development of flat roofs in all latitudes. On this subject, insurance companies have noted and publicized the fact that many building claims involve leaks from terraces, and that these are mainly located at the waterproofing upstands.

The importance of waterproofing pathology on flat roofs is highlighted in this dossier.