Preparation
The target surface must be clean, dry, sound and frost-free. Apply masking tape to adjacent surfaces and apply primer as required (refer to Americas Technical Manual,
Form No. 62-1112), before installing an approved back-up material
Application
- Apply Dow 756 SMS building sealant and tool so all joint sides are wetted out.
- Wet tooling of the sealant with liquid tooling aids is not suggested
- Remove any excess uncured sealant from applied surfaces using mineral spirits
- Remove masking tape immediately after sealant application to maintain neat and clean lines.
- Under low temperature and low humidity conditions, the curing time may be considerably extended.
Joint Design
Applying a thin sealant bead will allow more movement than a thicker bead. Recommended width-to-depth ratio is 2:1 where possible. A joint depth over backer rod should be 1/8" to 1/2" and joint width from 1/4" to 1". Dow Technical Service should be consulted for joint applications outside published guidelines. In all cases, movement of the joint should not exceed ±50 percent of the original joint dimension.
