By Athena Reschke, Project Specialist at Custom Building Products
What is the fastest – and best – way to build the mortar bed and waterproof a tiled shower? New technology has the answer to this common question.
The traditional shower mortar bed method (TCNA Detail B415) has been used for decades, but does have drawbacks. Primarily, it is a time-consuming process when installation speed is more important than ever. Issues with mortar saturation have also led many installers to use surface waterproofing (TCNA Detail B421 or B422) of the shower floor mortar bed instead of a shower pan liner beneath the mortar bed. This keeps the water out of the mortar bed and directs it down the drain, but you may still have to wait days for slow drying mortars and membrane materials to cure before installing tile.
Custom Building Products has solved these inherent problems with two rapid-curing products for preparing a shower for the installation of ceramic, glass and natural stone tile. The first product in this system is CUSTOM’s SpeedSlope™, a rapid-setting mortar bed that meets ANSI A108.1.
Following the B421 or B422 method, SpeedSlope is installed onto the subfloor of the shower stall
in the same way a traditional cement mortar bed is placed. It is shaped to fit the floor and sloped ¼” per foot to the drain. Because of its unique cement chemistry, it cures hard in less than 2 hours and is then ready to receive waterproofing. SpeedSlope is pre-blended and polymer-modified, so there is no need for jobsite mixing of sand and cement or the addition of liquid latex additive; just add water and mix to a dry pack consistency.
The second product in the shower system is RedGard® SpeedCoat™, an extremely fast curing, liquid-applied waterproofing membrane. RedGard SpeedCoat is used to waterproof the cured mortar bed floor and shower walls with a simple roll-on application. This membrane uses a cross-linking, moisture cure, polymer base to meet the demanding requirements of ANSI A118.10 and the IAMPO standards for shower pan liners.
Following TCNA method B421 or B422, the membrane is tied into the drain and carried up the walls. RedGard SpeedCoat’s cross-linking moisture cure technology will typically cure the membrane in less than one hour. Once it is dry to the touch, it is fully cured and ready for flood testing and the installation of ceramic tile.
When used together, SpeedSlope and RedGard SpeedCoat can prepare a shower in hours rather than days.