You have been asked to repair some damaged wallboard in an apartment complex currently undergoing renovation. As you are inspecting one of the damaged areas, you recognize that the area to be repaired is a fire-rated party wall. Are there any items of concern here, or can you proceed to patch the wall as you normally would?
Damaged fire-rated gypsum board systems must be repaired so that they are restored to their original fire-resistive condition. This must be accomplished so that the system assembly is consistent with that of the tested, fire-rated system.
Small holes can be patched to maintain the integrity of the fire-rated partition. To achieve this, you must first select patching material that is equivalent to the original product in thickness and core type (either Type X or proprietary Type X board), and slightly larger than the damaged area. This patch material must be mechanically fastened in the diaphragm. It is insufficient to secure the patch material with joint compound alone.
The area to be repaired should be enlarged to match the size of the patch material. The metal screw track should be secured to the inside edges of the damaged area. The patching material is then screw-fastened to the exposed face of the screw track with fasteners spaced no more than eight inches apart.
Exercise caution when cutting or fastening into stud cavities in order to avoid the hazard of electrical shock or the inconvenience of water leaks. Finally, the patched area should be taped and finished with joint compound to refurbish the fire- and sound-resistant characteristics of the wall along with its final appearance.
As an alternate to using screw track for mechanical attachment, you may choose to use one of several proprietary clip products designed and tested to provide support for mechanically attaching patch material. Manufacturers of these products should be contacted for specific installation instructions.
If the damaged area of wallboard exceeds 100-square-inches in 100-square-feet of gypsum system area, then it is necessary to cut all damaged material back to the original framing in order to make the repair. Inspect the existing framing and replace if necessary without exceeding the original framing spacing. The replacement board should be of the same core type and thickness as the original wall. Cut the material to completely cover the opening and fasten mechanically to the framing. Unbacked ends and edges should be supported with screw track. Finish the area with tape and joint compound as required.
Repair of multiple layer systems that require joints to be staggered between layers demands that face layers of gypsum board be removed beyond the area of the base layer joint, so that the staggered joint feature is maintained.
Click here to download an electronic copy of GA-225-08: "Repair of Fire-Rated Gypsum Board Systems". For additional information, call 1-800-NATIONAL® (800-628-4662).
Check the FAQs page of our website for a more complete explanation of how fire-resistance ratings work.