Head-of-wall fireblock systems and related wall assemblies
View Patent ↗The invention disclosed herein is directed to a fire retardant head-of-wall assembly configured to seal a linear head-of-wall construction joint or gap when exposed to a heat source such as a building fire. The inventive fire retardant head-of-wall assembly comprises a header track having an elongated intumescent strip affixed lengthwise on at least one of the outer sidewall surfaces of the header track. When exposed to a heat source such as a building fire, the intumescent strip is able to expand so as to at least partially fill the head-of-wall construction joint or gap; and in so doing, retard or prevent the spread of smoke and fire. The inventive fire retardant head-of-wall assembly has been certified as complaint with respect to Underwriters Laboratories, Inc.'s standards set forth in its Tests for Fire Resistance of Building Joint Systems—UL 2079.
1. A fire retardant head-of-wall assembly configured to seal a linear head-of-wall construction joint or gap when exposed to a heat source, comprising:
an elongated sheet-metal footer track;
an elongated sheet-metal header track confronting and vertically spaced apart from the footer track, the header track including a web integrally connected to a pair of spaced apart and downwardly extending sidewalls, the web having a top exterior web surface positioned immediately adjacent to a ceiling and a bottom interior web surface, each sidewall being substantially coplanar and having inner and outer sidewall surfaces, each sidewall having an upper sidewall portion adjacent to the web and a lower sidewall portion;
an elongated intumescent strip affixed lengthwise on at least one of the outer sidewall surfaces of the pair of sidewalls, the intumescent strip being positioned on the upper sidewall portion, the intumescent strip having an outer strip surface offset from the outer sidewall surface an intumescent strip offset distance;
a plurality of sheet-metal studs having upper and lower end portions, the studs being vertically positioned between the spaced apart and confronting footer and header tracks such that the lower end portions are received into the footer track and the upper end portions are received into the header track, each of the upper end portions of the plurality of studs being spaced apart from the bottom interior web surface of the header track a first gap distance that allows for ceiling deflections; and
wallboard attached to at least one side of the plurality of studs, the wallboard having a top linear end surface positioned apart from the ceiling a second gap distance that allows for ceiling deflections and defines the linear head-of-wall construction joint or gap, the wallboard having an elongated upper interior wallboard surface in linear contact with and bearing against the outer strip surface of the elongated intumescent strip.
2. The fire retardant head-of-wall assembly of claim 1 wherein the first gap distance and the second gap distance are the same or about the same.
3. The fire retardant head-of-wall assembly of claim 1 wherein the first gap distance and the second gap distance each range from about ⅛ inch to about ⅝ inch.
4. The fire retardant head-of-wall assembly of claim 1 , further comprising a plurality of fasteners securing the upper end portions of the plurality of studs to the header track, each fastener extending through one of the pair of sidewalls of the header track and the upper end portion of one of the plurality of studs, each fastener including a fastener head that protrudes away from the outer sidewall surface of the sidewall a fastener head offset distance, the fastener head offset distance being about the same or slightly less than the intumescent strip offset distance.
5. The fire retardant head-of-wall assembly of claim 4 wherein the elongated sheet-metal header track includes a plurality of vertically aligned slots positioned along at least one of the pair of downwardly extending sidewalls, with each fastener extending through one of the plurality of slots.
6. The fire retardant head-of-wall assembly of claim 5 wherein each vertically aligned slot has a length that is about twice the first gap distance.
7. The fire retardant head-of-wall assembly of claim 6 wherein the fasteners are positioned about in the middle of its respective vertically aligned slot.
8. The fire retardant head-of-wall assembly of claim 5 wherein the intumescent strip partially covers each of the plurality of vertically aligned slots.
9. The fire retardant head-of-wall assembly of claim 1 wherein the intumescent strip has a width that is at least about twice the first gap distance.
10. The fire retardant head-of-wall assembly of claim 9 wherein the top linear end surface of the wallboard is positioned perpendicular and about midway along the width of the intumescent strip.
11. The fire retardant head-of-wall assembly of claim 1 , further comprising a fire retardant epoxy adhesive interposed between the intumescent strip and the at least one of the outer sidewall surfaces of the pair of sidewalls.
12. The fire retardant head-of-wall assembly of claim 1 wherein the elongated sheet-metal header track has a U-shaped cross-section.
13. The fire retardant head-of-wall assembly of claim 1 wherein each of the plurality of sheet-metal studs has a C-shaped cross-section.