Showers in group settings, such as fitness clubs and college residences, are subject to much more demanding conditions than a typical residential shower. These conditions must be understood and accounted for when the shower area is being built. It is essential to create a waterproof and vaportight area that will prevent moisture damage and mold growth. It is also important to build a space that can be effectively maintained while minimizing downtime when the showers are not available for use.

Moisture damage was evident in the unsightly discoloration on the white carrara slabs in the old showers.

This article follows the reconstruction of a number of showers in a residence dorm at McDaniel College in Westminster, Md. The work was completed last summer, while the residence was empty for the summer break. The objective was to create an attractive and functional space that would eliminate the ongoing maintenance and progressive damage that was taking place in the existing shower areas. The work was not scheduled to start until part way through the summer so there was also a need to complete the job in less time than would normally be the case.

The fi rst step in reconstruction was to frame the partition walls and install the grid for the new dropped ceiling.

The original design was typical of many multi-shower areas. It featured white carrara slabs on the walls and 1-inch-by-1-inch mosaic tiles on the floor. The water management system was a traditional water-in/water-out design. The floor tiles were set on sloped mortar beds which had been installed over copper pan liners for waterproofing. The drains were traditional clamping ring drains with weep holes at the bottom to allow moisture to flow out of the mortar bed at the bottom of the assembly. The shower areas were attractive in their day but had started to leak badly and were in desperate need of structural improvement and refreshing. There are a total of five floors in the residence and the shower area on each floor is immediately above the one below. The floors were leaking to the extent that it was necessary to fix the plaster ceilings in the shower areas each year. Moisture was also wicking up the marble walls creating an environment for mold growth and making them unattractive and dirty looking.

Spot-bonding the panels to the block walls allows them to be set with straight and precisely aligned corners.

Strip Down

To start the project, the walls were stripped down to the concrete block, the mortar beds and copper pans were removed from the floors, and the plaster coating and steel stringers were removed from the ceilings. All of the concrete block walls were left intact and partition walls were framed with 2x4s to complete the shell for the new space. The next step was to install tracks for a dropped ceiling. The installed tracks served as the upper border for the new white subway tiles that were to be installed on the walls.

Local contractor Charles Eckard decided to install a waterproof building panel system on the walls as part of the overall waterproofing system for the showers. The wall panels would be tied in with a sheet-applied waterproofing membrane on the floor and integrated bonding flange drains to create an environment that was completely waterproof and vaportight before the tiles were installed. In the past, when he needed to build a waterproof wall over concrete block, Eckard would spot mount concrete board to the block walls, fill the gaps and seams in the concrete board and then cover the concrete board with a sheet-applied bonded waterproof membrane. By using the new building panel system he would eliminate an entire step from the previous method.

PVC trim profi les in the corners accommodate expansion and contraction of the tiles in these critical transition areas.

The panels he used have an extruded polystyrene foam core with a factory applied reinforcing layer and fleece webbing on both sides. The panels are available in a variety of thicknesses-Eckard spot-bonded 3/8-inch thick panels to the block walls and fastened 1/2-inch thick panels to the wood framing. The spot-bonding was done by putting dabs of thin-set mortar in one-foot intervals on the boards. Each board was then pressed onto the block wall and plumbed using a level. It took a bit of practice to get the spots just right but the lightweight panels were very easy to handle and maneuver.

(This picture and the next) The waterproofi ng membrane is set over a seam where two building panels meet so no moisture can penetrate the surface.

The panels were attached to the wood framed walls using screws and washers, placed at 12 inch intervals. All of the panel seams and fastener penetrations were covered with a thin strip of waterproof membrane to ensure that there were no locations where moisture could penetrate the wall. The sheet-applied waterproof membrane was bonded onto the top of the floor and to the bonding flange on the drain using thin-set mortar. The wall-to-floor intersections were also waterproofed using a 5-inch strip of the membrane. The result is a completely waterproof and vaportight room where all moisture will either be channeled down the drains or will evaporate back into the air-nothing will penetrate into the structure where it can cause mold growth or long-term damage.


Eckard recommends using the largest panels possible (most are available in 4-feet-by-8-feet sheets) to minimize the number of seams. The primary benefits of using the building panel system were eliminating the need to waterproof the wall, and the overall ease and speed of installation because of the light weight of the panels. Using the larger panels allows the crew to maximize these benefits.

Hygiene is also an important consideration in any shower and the needs are even greater in higher traffic areas like dorm showers. To make the shower areas easier to clean and to reduce maintenance, trim profiles were installed at wall-to-wall intersections and at wall-to-floor transitions instead of using sealant. The profiles provide an easy-to-clean, low maintenance surface. They also help protect tiles and grout by accommodating expansion and contraction of the tile at these transitions.

The outside edge of the tiled shower wall is protected using a metal trim profi le that is anchored behind the building panel on the wall.

One particular challenge arose because only the shower area was being renovated. There was a glazed block wall near the vanities in the room that was in good condition so it was not touched during the demolition. The new tiled wall in the shower area was thicker than the existing glazed block wall, so a solution was needed for the seam where the two walls meet. The crew installed a metal transition profile behind the building panels and tiles to create a clean, smooth finish on the outside edge of the tiled shower wall.

In the end, the goals of the project were achieved, and in less time than this type of project would normally require. The new showers are clean, attractive and will be very easy to maintain. The tiles provide a durable, hygienic, and decorative covering that makes the room look great. But it’s the structure underneath that will make these showers long-lasting and economical to maintain.