Koster Repair Mortar Plus - Fast Setting, Repair Mortar - W 532 025 -

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KOSTER Repair Mortar Plus is a watertight, fast setting, slightly expanding repair mortar with excellent adhesion to building material substrates. When used with KOSTER SB Bonding Emulsion, it may be used as a polymer-modified cement mortar.

Unit Size 55 lb bag (W 532 025)

Fields of Application Use KOSTER Repair Mortar Plus for watertight repairs and touch ups. It can be used for the installation of fillets in wall/floor junctions that are exposed to pressurized water before application of bitumen thick film sealants and cement based coatings. The material can also be used for underfilling machine foundations and filling ruptures and oversized joints.

Substrate The surface must be sound and clean, free of oil and grease. The material can be applied to all cementitious substrates. Before installing a fillet on exterior basement walls, prime with KOSTER NB 1 Grey (coverage approx. 0.8 lb/ft2 ).


KOSTER American Corporation is a subsidiary of KOSTER Bauchemie AG of Germany.

Founded in 1982 KÖSTER BAUCHEMIE AG specializes in the development and production of high-quality waterproofing products and systems. Today, KÖSTER forms a group of more than 20 companies with worldwide activities in more than 50 countries. Its headquarters are located in Aurich, Germany.

Our R&D facility, production and technical department are all located on the same campus in Virginia Beach, VA. This allows each department to work closely together to ensure each product conforms to the highest standards of quality. 

KOSTER operates two production facilities in Virginia Beach. The liquid facility produces all of our epoxy coatings while the powder facility produces our self-leveling underlayments as well as other cementitious waterproofing products. 
We place tremendous value on producing our products ourselves in order to ensure the highest level of quality control from development to application. We strongly believe in providing our customers with an excellent and safe experience with our products.