Head-of-Wall & Construction Joint Firestop
The head-of-wall joint — the gap where a fire-rated wall meets the floor or roof deck above — is not a static hole. The deck deflects as loads change, so this joint moves, and a firestop that cannot move with it will crack and fail. Joints are their own category of firestop, tested differently from penetrations.
Why the head-of-wall is different
Penetrations (a pipe through a wall) barely move. A head-of-wall joint can open and close repeatedly as the structure above deflects. So it needs a rated joint system with a defined movement capability — tested to ASTM E1966 (UL 2079), not the penetration standard. Use a rigid product and you'll see cracks at the first deflection cycle.
Elastomeric sealant, spray & joint strip
- Elastomeric sealant — Metacaulk 1200 in caulk, self-leveling or spray grade flexes with the joint; spray covers long linear joints fast. See firestop sealants.
- Joint strip — pre-formed intumescent strip that tucks into head-of-wall and perimeter joints, supplied in long rolls. See joint strip & wrap products.
Match the movement and the rating
Pick a listed joint system whose movement class covers your expected deflection and whose rating matches the wall. The UL system spells out the joint width, the material, the depth and the movement percentage. Send us the joint detail and expected movement and we'll pull the right system and product.
Frequently asked questions
Send your penetration schedule and we'll pull the UL system and quote it — distributor pricing, same-day shipping, free submittal support.