Construction joints are subject to movement. To waterproof construction joints permanently, an elastic material is required. KOSTER Joint Sealant FS is elastic, resistant to mechanical stresses, UV radiation, and aging. KOSTER Joint Sealant FS is also resistant to aggressive chemicals.
The sealer must also permanently adhere to the joint flanks. The substrate must be stable, clean, dry, and free of bond inhibiting substances. Prime the flanks with KOSTER FS Primer.
KOSTER Joint Sealant FS is installed only to two opposing joint flanks. It allows the material to expand across the construction joint. To separate the joint sealing from the bottom, install a backer rod into the joint before applying the material. To avoid damage caused by tension stresses, the joint sealant is applied in thicknesses depending on the measurements of the joint. The proportion of the applied sealant should be 1 : 1 to 1 : 2 (height to width of the joint).
Always adhere to the specifications in the respective Technical Guidelines.