#MAPEITechTip: When installing tile/stone/glass in a steam room what are some factors to consider?

The Romans paved the way for many of the modern uses of tile today in bathrooms, kitchens and water features like pools, fountains and water treatment plants that span the construction landscape within industrial, commercial and residential installations. The most notable use of tile engineering was in the Roman baths of the natatoriums and steam rooms of the caldariums.

Although tile had been used on exterior applications (such as walls, floors and roofs), never before had it been engineered as part of an elaborate furnace system. The water and superheated air of the Roman baths reached temperatures of over 100ºF and 100% relative humidity as a furnace heated the air drawn underneath the floor of the caldarium in order to heat the stacks of thin square tiles known as pilae.  This hot air then rose up through hollowed-out bricks that lined the walls before exiting through chimneys.

In modern architecture, considering both the environment and degree of heat and moisture exposure that the tile and stone will be subjected to is critical. In a steam room, additional factors such as high heat, high humidity, steam and condensation are added into the mix, where either full or even partial failure of an installation can add to labor and material costs, and customer dissatisfaction. 

During the design phase, it is important to quantify the degree of water and heat exposure and also take into account the type of installation—residential combination steam shower compared to a commercial steam room.  Since there are many factors involved when installing steam showers, always refer to both the TCNA Environmental Exposure Classifications and the appropriate TCNA CAD Detail (TCNA Handbook) prior to product selection and installation. If improperly designed, a steam room can lead to serious and costly repair issues—mold growth, failure of the wall, floor and ceiling assemblies, and safety issues resulting from loose tile/stone/glass. 

The TCNA Environmental Exposure Classifications “Res” (Res 1-7) for residential and “Com” (Com 1-7) for commercial include a detailed description of the exposure conditions for each designation, in this case, a steam room would be a RES 4 or COM 4.  

Although both installations are exposed to moisture and heat, what about exposure time, manner of use and cleaning regiments? Are they equal? Within either installation environment, the tile/stone/glass installation must perform at elevated temperatures and high moisture content – requiring the entire assembly to deform and move due to thermal growth and shrinkage (as the steam room cycles on/off).  For example a commercial steam room ramps up from a typical ambient temperature at 73ºF [23ºC] at 50% relative humidity to a working environment saturated with super-heated water vapor at approximately 115ºF [46ºC] with 100% relative humidity (keep in mind that steam room design requires a vapor barrier and proper placement of insulation). 

Keeping the following factors in mind will minimize modes of failure:
 *Isolating the wood or steel studs and exterior wall from any water vapor penetration—using an approved insulation for steam rooms, vapor barrier that meets ASTM E96, and a backer board designed for wet & humid environments.
 
*The ceiling slope should be at least 2’’ (5 cm) per foot toward a wall or over the floor drain to keep hot droplets off of occupants.
 
*Apply a waterproofing designed for steam room applications to the backer board such as Mapelastic AquaDefense (when used in conjuction with a vapor barrier) or Mapelastic 315, ensuring a continuous homogenous coat with no pinholes or breaks in the coats.
 
*Choose a mortar designed to perform in the harsh conditions of a steam room—high bond strength and deformability as the tile assembly shrinks and expands, optimally Granirapid® or KerabondT/Keralastic™ System or for translucent glass tile Adesilex™ P10 with Keraply™.
 
*Using a grout that has low water absorption, and high abrasion resistance will stand up the more rigorous cleaning and chemical exposure typically associated with maintaining steam rooms. Kerapoxy IEG CQ is the ideal product selection in commercial steam rooms that will be used on a continuous basis, for residential steam room/shower combos Kerapoxy CQ is a great choice.