We are often asked if a condition we observe “meets code”, as if this were the sole determining factor in whether something was done correctly. Quite often the question does not have a simple answer. An illustration of this is found in the requirement for shower pan liners. In the 2004 Florida Building Code, Plumbing you will find that while shower liners are generally required there is an exception for showers on the first floor:

417.5.2 Shower lining. Floors under shower compartments, except where prefabricated receptors have been provided, shall be lined and made water tight utilizing material complying with Sections 417.5.2.1 through 417.5.2.4. Such liners shall turn up on all sides at least 2 inches (51 mm) above the finished threshold level. Liners shall be recessed and fastened to an approved backing so as not to occupy the space required for wall covering, and shall not be nailed or perforated at any point less than 1 inch (25 mm) above the finished threshold. Liners shall be pitched one-fourth unit vertical in 12 units horizontal (2-percent slope) and shall be sloped toward the fixture drains and be securely fastened to the waste outlet at the seepage entrance, making a water-tight joint between the liner and the outlet.

Exceptions:
1. Floor surfaces under shower heads provided for rinsing laid directly on the ground are not required to comply with this section.
2. Shower compartments where the finished shower drain is depressed a minimum of 2 inches (51 mm) below the surrounding finished floor on the first floor level and the shower recess is poured integrally with the adjoining floor.

This same exception is found in the 2004 Florida Building Code, Residential at:

SECTION P2709 SHOWER RECEPTORS

P2709.1 Construction. Shower receptors shall have a finished curb threshold not less than 1 inch (25 mm) below the sides and back of the receptor. The curb shall be not less than 2 inches (51 mm) and not more than 9 inches (229 mm) deep when measured from the top of the curb to the top of the drain. The finished floor shall slope uniformly toward the drain not less than 1/4 unit vertical in 12 units horizontal (2-percent slope) nor more than 1/2 inch (13 mm), and floor drains shall be flanged to provide a water-tight joint in the floor.

P2709.2 Lining required. The adjoining walls and floor framing, enclosing on-site built-up shower receptors shall be lined with sheet lead, copper or a plastic liner material that complies with ASTM D 4068 or ASTM D 4551. The lining material shall extend not less than 3 inches (76 mm) beyond or around the rough jambs and not less than 3 inches (76 mm) above finished thresholds. Hot mopping shall be permitted in accordance with Section P2709.2.3.

Exceptions:
1. Floor surfaces under showerheads provided for rinsing laid directly on the ground.
2. Shower compartments where the finished shower drain is depressed a minimum of 2 inches (51 mm) below the surrounding finished floor on the first floor level and the shower recess is poured integrally with the adjoining

It is interesting that the code specifies the height that the lining material must extend up the wall and other installation details but then just drops any requirement to protect this area if the builder recesses the shower floor at the time he pours the house slab. The problem we have seen is at the point where the walls attach to the slab, a joint is created that if not carefully protected allows water to seep into the wall system and can serve as a starting point for mold and/or rot. If a liner were installed it would be required to extend up the wall and protect this transition area, but once the liner is eliminated the requirement becomes unclear. The builder often treats this as any other interior partition wall except that it has moisture resistant sheathing applied to the shower side and that side usually receives a tile finish. Any moisture entering the system through the grout joints will travel down the wall to the slab and then along the slab to adjacent areas, there is seldom any provision made to stop this from occurring.

The exception to the requirement for a shower liner does not exist in the International Codes. That is their way of making sure the builder does not over look the need to seal this area. A better answer for Florida builders is to understand that the exception eliminates the requirement for the installation of a shower lining, but that leaves you with a problematic transition that needs to be protected. Few items in the code can be eliminated without some alternative measures being put in place to accomplish the necessary objectives. The code is a “minimum” standard and therefore the elimination of any requirement without compensating adaptations will often result in an unsatisfactory condition.

If you have any questions regarding these or other code provisions, please contact Gary Pailthorp, PE, CBO, CFM at gpailthorp@brackenengineering.com.

In furthering their philanthropic endeavors, the employees of Bracken Engineering volunteered time on November 25, 2009 along with a quarter-long food donation drive raising enough food to feed over 20 families this Christmas. The donated time and food were for the benefit of the clients of Metropolitan Ministries of Tampa Bay. During their volunteer time at Metropolitan Minitries, the Bracken Engineering staff provided “Holiday Traffic Management” services.

Metropolitan Ministries is a Tampa based organization whose mission is to “care for the homeless and those at risk of becoming homeless in our community through services that alleviate suffering, promote dignity and instill self-sufficiency…”

Bracken Engineering is proud to support Metropolitan Ministries throughout the year and especially during the Holiday season.