Substrate preparation and waterproofing

Repair and restoration of existing waterproofing

When restoring old buildings one frequently finds a great array of different old waterproofing and protective coatings have been applied.

If these still bond firmly to the substrate they may simply be left in place and worked over. An exception to this rule is an existing tar-based coating: these always have to be removed completely, as bitumen and tar are not compatible.  As a rule the substrate must be cleaned thoroughly and defect areas must be properly made good before the new waterproofing system is applied.

For the repair of old bitumen waterproofing or coatings, the applicator has two options at his disposal:

Working over the existing surface with the solvent-containing  bitumen coating BOTAMENT B 97 L. The solvent contained in the coating ensures that the new contact layer bonds optimally to the old substrate.  

BOTAMENT B 97 L receives a scattering of dried quartz sand while still fresh.   

Depending on the weather conditions a drying phase of between 4 to 5 days ought to be allowed to ensure the solvent can evaporate completely. After this period the bitumen thick coating or RD 2The Green 1 can be applied.

Application of BOTAMENT RD 2The Green 1. The fast, multi-functional reactive waterproofing bonds really well with the substrate. It does not contain any solvents or bitumen. No scattering is needed with this product. After the scratch coat has fully cured the new waterproofing, either the bitumen thick coating or RD 2The Green 1 , can be applied.

Expert Tip:

BOTAMENT RD 2 The Green 1 is very useful for the partial restoration and repair of defect roof waterproofing. Where joints need to be worked on we recommend using the sealing tape BOTAMENT SB 78.


Clean the substrate, e.g. with a pressure washer.


Apply scratch coat as a bonding course.


Produce the wall-floor connection with BOTAMENT SB 78.


Apply the 1st and 2nd layer of BOTAMENT RD 2 THE GREEN 1.