The gypsum industry has worked hard to promote special drywall partitions instead of masonry for fire walls in multifamily dwellings. However, there are some very good reasons to choose masonry.
WHAT ARE FIRE WALLS?
As defined by model building codes, fire walls are continuous, noncombustible assemblies that extend from the foundation through the roof to a parapet wall. They must be built to remain stable despite the collapse of construction on either side in a fire.
Masonry is a universally accepted way to construct fire walls separating townhouse units. It meets the performance requirements set forth in the BOCA Basic Building Code, Standard Building Code, and Uniform Building Code.
Masonry fire walls at least 8 inches thick qualify a multifamily dwelling for the Dwelling Policy Program of ISO Commercial Risk Services Inc. This body classifies risk categories for many insurance companies and thus affects property insurance rates.
EFFICIENT USE OF SPACE
A load-bearing wall of nominal 8-inch block, faced on each side with 1/2-inch gypsum board on 1 1/2-inch drywall channels is only 11 5/8 inches thick, yet provides full fire protection, more than 50 STC sound isolation, an appropriate finish, and space for utilities in the cavities between drywall channels.
EASE OF CONSTRUCTION
Another major advantage masonry construction has over drywall separation walls is its simplicity. For masonry fire walls to perform as intended, they need only be constructed according to standard practices of good masonry workmanship.
Even a properly built drywall separation wall will need replacement after the fire is extinguished. A masonry fire wall, on the other hand, generally survives exposure to a fire with little or no damage.