Posted by leechai6 days ago
Firestop spray on top of mineral wool
Firestop spray on top of mineral wool safing insulation... What would be the condition of the firestop spray on the floor bracket (will it be entirely covered by firestop spray)? Also what would be the minimum lapping needed of the mineral wool safing insulation?
1 Reply
Posted by Gael5 days ago
The answer depends on the specific tested system (the UL CW-S listing or the European assessment for CFS-SP WB) used on the project. The exact thicknesses and overlaps must come from that system’s detail drawing. As a typical guide:
- Floor bracket: The bracket is not left exposed. Pack mineral wool tightly around it, then spray the joint spray continuously over the mineral wool and the bracket, so the bracket is fully covered at the required wet thickness and the seal has no gaps.
- Mineral wool: Install it compressed into the joint at the percentage the system specifies (often about 25–33%). Tightly butt and compress the joints between pieces with no gaps. Recess it below the slab top surface to the depth the system specifies.
- Spray overlap: The spray typically overlaps onto the slab edge and the curtain wall or mullion by a minimum of about 13 mm, but confirm this against the listing.
Please share the curtain wall and joint details so we can confirm the applicable Hilti system and its exact requirements.
MOZAECC.ZATeam@hilti.com