Here you will find the most frequently asked questions and answers 24 hours a day, 7 days a week. However, the technical issues may be different for each project. So if your roof is complex, we recommend that you contact our technical department. They will be happy to help you.

Bituminous roofs sometimes tend to “sweat out” certain bitumen particles, resulting in a brown discoloration of rainwater and a slight acidification of the water. The solution to this phenomenon is very simple, it suffices to apply a coat of paint (2-layer) type “DERBISILVER S” on the waterproofing after thoroughly cleaning the roof.
When designing a roof where the rainwater will be used for sanitary purposes, it’s better to opt for a waterproofing type DERBIGUM AQUATOP or DERBIBRITE NT. These membranes are specially made not to modify the pH value of the rainwater coming from the roof.

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