By Greg Mowat, Forensic Tile Consultants
A linear drain is a rectangular-shaped drain installed at the entrance, along the wall or center of a shower floor. Linear drains function by allowing water to flow through the drain and into a trough, or channel, beneath the shower floor. The shower water flows via a single slope toward the drain opening.
Drains are fundamental to the performance of surface water management. Weep holes assist in the evacuation of water, keeping it from collecting on the waterproofing under the tile assembly. Likewise, linear drains are used for egress/evacuation of surface water from any site, preventing long-term damage from ponding or trapped water. Linear Drains are used for egress/evacuation of water reaching the underlying waterproof membrane.
Linear drains can be installed in regular showers, curbless showers, gang showers, steam rooms and locker rooms:
- Linear drains have become popular with usage in ADA (The Americans with Disability Act) compliant showers. Also known as a barrier-free shower floor and curbless shower.
- Linear drains are suitable for universally accessible wet spaces.
- Linear drains allow for large-format tiles to be installed in a shower with one single pitch to the drain.
- Linear drains feature low profiles while offering high-capacity drainage, making them ideal for barrier-free applications.
- Membrane adhesion assures a watertight seal with the waterproofing membrane.
- Linear drains are available in many widths and lengths.
- Linear drains are available in custom sizes, and available in manufacturer kits.
- Drain covers, strainers and grates should be chosen for their ability to properly evacuate water during shower usage.
- Metal drain grates are available in many finishes, colors and sizes.
- Grates may have slotted or circular drain hole configurations, or a tileable grate with a narrow slot around the perimeter of the drain.
- Installed linear drains are easy to access and maintain.
- Linear drain location can be between the shower receptor and the bathroom floor to allow all water to flow toward the door opening, as is common with a curbless shower.
- The immediate adjoining space to any showers without thresholds is considered a wet location and must comply with the requirements of the building, residential and electrical codes.
- With curbless showers make sure the bathroom floor includes waterproofing.
- Always install linear drains following linear drain manufacturers’ requirements.
- Various linear drain manufacturers offer compatible waterproofing for adjacent floors and walls in showers.
- A complete linear drain system is advised when you as the contractor are performing the installation.
- In addition to showers, linear drains are suitable for installation on floors in: Kitchens & Bars, Restaurants, Laundry Rooms Fitness Centers, Swimming Pools and Decks, and Fountains, including surrounding Hard Surface Areas, Sidewalks & Walkways and Exterior areas where hoses are used.
- Common length linear drain sizes include 24”, 32”, 36”, 40”, 48”, 54” and 60”. Custom sizes are usually available with advance ordering.
- Linear drains are suitable for usage with thin-bed sheet membranes, liquid waterproofing and full mortar bed installations with underlying waterproofing. Follow waterproofing manufacturer’s installation guidelines along with linear drain installation guidelines.
- A curb between the shower and adjacent floor may be a hazard in a shower creating a greater opportunity for a slip, trip, or fall for occupants.
- Linear drains require no curbs but can still be installed in showers with curbs, because the linear drains are installed to capture water flow efficiently.
- Linear drains are suitable for roll-in showers and aid in mobility for the disabled, elderly and persons recovering from surgery. Linear drains increase safety and accessibility for homeowners and occupants.
- Linear drains grates and covers can be easily removed by hand and wiped down to eliminate soap scum, hair and other obstructions to allow, consistent drainage of water.
Tips for successful linear drain installations:
- Planning and coordination between the general contractor, developer, plumber, tile installer, architect, designer and homeowner will ensure successful installations.
- Where no plumber is installing the linear drain, a contractor is responsible for the same work.
- Read and follow manufacturer instructions on the entire installation.
- A complete linear drain system is advised, including linear drain and waterproofing.
- Linear drain should be properly supported.
- Drains with pre-pitched bodies are suggested.
- Drain covers/grates/strainers should be chosen for their ability to properly evacuate water in the shower and may not be required in a shower with multiple shower heads.
- The linear drain should be installed at the proper height, depth and level from side to side for the tile assembly. Coordination between the plumber and other parties involved may be necessary.
- The finished floor of the receptor shall slope uniformly from the sides toward the drain not less than 1/8” per foot (10.4 mm/m), nor more than ½” per foot (41.6 mm/m).
- Hot-mopped waterproofing, sheet waterproofing, liquid applied waterproofing or trowel applied waterproofing is properly connected to the linear drain assembly for the surface flow of water and drainage below away from the waterproofing.
- Water test the liner drain assembly prior to tile installation.
- Protect the waterproofing from damage during installation of the tile assembly.
Follow manufacturer’s directions for finishing and securing the grate. When installing tile in a grate, use stainless steel expanded metal lath. Material other than stainless steel wire reinforcing is subject to trapped water and corrosion.
