Fire resistive joints at base of wall

[Chrisjoneill]

A 1 or 2 hour rated wall on a slab on grade, is the base of the wall supposed to be fire caulked if the drywall is tight to the floor? IBC 2022. there are bottom of wall fire resistive joint systems that show a gap in drywall that is filled with caulk but ive never specified it this way, only at top of walls or other locations that have a legitimate gap in construction. I have seen UL wall assemblies that show an optional sealant at the base but no fire caulk specified. I have a builder client who we did not do the plans for saying that the AHJ is saying the base of wall needs to be fire caulked. The client is looking for me to provide a code section that says they don't need to fire caulk the base of the wall...have i been getting away with one on not having this detail specified?

715.3 Fire-Resistance-Rated Assembly Intersections​

Assembly
Diagram
Joints installed in or between fire-resistance-rated walls, floor or floor/ceiling assemblies and roofs or roof/ceiling assemblies shall be protected by an approved fire-resistant joint system designed to resist the passage of fire for a time period not less than the required fire-resistance rating of the wall, floor or roof in or between which the system is installed.
Exception: Fire-resistant joint systems shall not be required for joints in the following locations:

1. Floors within a single dwelling unit.
2. Floors where the joint is protected by a shaft enclosure in accordance with Section 713.
3. Floors within atriums where the space adjacent to the atrium is included in the volume of the atrium for smoke control purposes.
4. Floors within malls.
5. Floors and ramps within parking garages or structures constructed in accordance with Sections 406.5 and 406.6.
6. Mezzanine floors.
7. Walls that are permitted to have unprotected openings.
8. Roofs where openings are permitted.
9. Control joints not exceeding a maximum width of 0.625 inch (15.9 mm) and tested in accordance with ASTM E119 or UL 263.
10. The intersection of exterior curtain wall assemblies and the roof slab or roof deck.

 

[Yankee Chronicler]

A 1 or 2 hour rated wall on a slab on grade, is the base of the wall supposed to be fire caulked if the drywall is tight to the floor? IBC 2022. there are bottom of wall fire resistive joint systems that show a gap in drywall that is filled with caulk but ive never specified it this way, only at top of walls or other locations that have a legitimate gap in construction. I have seen UL wall assemblies that show an optional sealant at the base but no fire caulk specified. I have a builder client who we did not do the plans for saying that the AHJ is saying the base of wall needs to be fire caulked. The client is looking for me to provide a code section that says they don't need to fire caulk the base of the wall...have i been getting away with one on not having this detail specified?

I think you've been getting away with it.

Beyond that, I can't recall ever seeing a wall where the sheetrock was installed tight to the floor. What usually happens is the sheetrock is installed horizontally. The ceiling height is 8'-0-1/2", which gives the sheetrockers a half inch to get something under the lower panel and push it up tight against the upper panel. That leaves a half-inch gap, which needs to be protected if the wall has a rating.

 

[Tim Mailloux]

In most cases I detail rated gypsum bd walls so there is roughly a 1/2" drywall gap at the top and the bottom. That way I can visually verify that the gaps have been fire safed. I do the same for acoustically rate walls, but replace the fire caulk with acoustical caulk.

 

[Yankee Chronicler]

In most cases I detail rated gypsum bd walls so there is roughly a 1/2" drywall gap at the top and the bottom. That way I can visually verify that the gaps have been fire safed. I do the same for acoustically rate walls, but replace the fire caulk with acoustical caulk.

That's a good detail, but do the 'rockers actually pay any attention to the 1/2" gap at the top?

 

[Tim Mailloux]

That's a good detail, but do the 'rockers actually pay any attention to the 1/2" gap at the top?

In the rare cases they don't, its gets documented in a field report and corrected.

 

[Chrisjoneill]

I think you've been getting away with it.

Beyond that, I can't recall ever seeing a wall where the sheetrock was installed tight to the floor. What usually happens is the sheetrock is installed horizontally. The ceiling height is 8'-0-1/2", which gives the sheetrockers a half inch to get something under the lower panel and push it up tight against the upper panel. That leaves a half-inch gap, which needs to be protected if the wall has a rating.

oof, hate when i do that and find out after that its required, i find this 1/2" gap less in commercial construction that has less standard ceiling and framing heights, the drywall is often pretty tight to the slab.

 

[Yankee Chronicler]

oof, hate when i do that and find out after that its required, i find this 1/2" gap less in commercial construction that has less standard ceiling and framing heights, the drywall is often pretty tight to the slab.

Why aren't the ceiling heights detailed to require a ceiling height that allows the gap?

Why don't the wall type details show and call for the gap -- and the joint seal?

 

[Yankee Chronicler]

A 1 or 2 hour rated wall on a slab on grade, is the base of the wall supposed to be fire caulked if the drywall is tight to the floor? IBC 2022. there are bottom of wall fire resistive joint systems that show a gap in drywall that is filled with caulk but ive never specified it this way, only at top of walls or other locations that have a legitimate gap in construction. I have seen UL wall assemblies that show an optional sealant at the base but no fire caulk specified. I have a builder client who we did not do the plans for saying that the AHJ is saying the base of wall needs to be fire caulked. The client is looking for me to provide a code section that says they don't need to fire caulk the base of the wall...have i been getting away with one on not having this detail specified?

The code requires a listed joint seal assembly where two rated walls intersect, or where a rated wall and a floor intersect. The U.L. wall details show wall details, not any rated joint seal assemblies at the top, bottom, or ends of the rated wall assembly.

 

[steveray]

In the rare cases it gets caught in the field , its gets documented in a field report and corrected.

Fixed it for you…