The sealing compound for bitumen can be used to seal dormers and penetrations as a barrier against building materials containing bitumen. It functions as an alternative to PE film barriers. For this purpose a sealant bead with a minimum thickness of 3 mm is applied to the joint.
Adhesion on moist, smooth, non-absorbant substrates is achieved even without using primers. The maximum joint width should not exceed 10 mm and the sealant is only suitable for joints that show little movement, due to its plastic properties. Because of its excellent adhesive power it tends to become stringy which can be avoided by jerking the cartridge away.
OTTOSEAL® A 250 remains slightly sticky; therefore face joints must be sealed afterwards with OTTOSEAL ® S 110 or S 120, which cure with non-sticky surfaces to protect the sealant surface from being soiled.
OTTOSEAL® A 250 is neither suitable for Styropor® oder Styrodur®, for expansion joints in buildings, skirting boards nor for sealing in underwater areas.