6 Reasons to Consider a Linear Drain

When it comes to designing the perfect bathroom shower, the styles that can be achieved are only limited by the requirements of the materials. While not always unsightly, the drain is an expected and familiar, boring element in most homes. The traditional result is a round or square drain in the middle of the shower stall floor, with a noticeable grade to the tile sloped around it. To update the look and break out from the old style, it’s time to switch drains.

Decorative and in-demand, linear drains remove the odd, four-corner slope from tiled shower stalls to offer a more effective alternative, without the risk of a puddle of dirty water around a slow drain. They can be hidden under a sturdy grate, or tiled in the same design as the surrounding floor, making it almost invisible. Breaking from the traditional provides more design control, and a more effective, more hygienic drain. When upgrading your shower or bath, the linear drain is worth a look.   

What Is a Linear Drain?

Once found exclusively in commercial bathrooms and locker rooms, the linear drain has come a long way. Also called a trough drain, or a trench drain, the linear drain is really a channel built into the floor of the shower to collect water before sending it to the drain outlet. They are stylish and customized, unique to your space. The water is pulled to a long and narrow trough at one end of the shower, collecting more water at once without pooling at your feet. The pre-pitched channel then directs the water to the hidden outlet and down the drain.

The floor must be gently sloped in one direction, toward the drain, so that the water follows gravity with fewer obstacles, making the floor safer. The wide grate helps keep debris from clogging the drain to further prevent puddles and slipping hazards. The channel cover can be made of metal grids or tooled into custom patterns, depending on the manufacturer. These grates can replace curbs or barriers as a way of keeping the water in the shower area, simply by lining the shower threshold with the channel. There are many ways to utilize the linear drain in a residential bathroom or shower layout.

Important Features of a Linear Drain

There are many options to consider with these drains. The necessary tools, products, and grading of the shower floor are all influenced by the layout of the room, the existing plumbing, and the intended placement of the linear drain. The design of the shower area determines the kind of channel and installation available, so it is important to have the details ironed out before you buy. Linear drains offer unique solutions to common bathroom or shower experiences, as well as the customized style. Consider the different features to help make the final decisions to the room design.

Drain Sizing

The size channel you choose is dependant on the size of the shower area and the size of the waste line, or drain, that it can accomodate. The average residential shower has a 2” waste line, which can usually handle water pouring into the shower area at a rate of 9 gallons per minute (GPM) without flooding. It’s recommended to plan on placing a 2” drain for every 30” of channel. For larger coverage areas, connecting multiple 2” drains along the channels and directing the channel to a 3” waste line can increase the flow rate to 21 GPM.

Another feature with these drains is their versatility. Many linear drain channels come in standard, preset lengths, ready to install. The standard minimum channel length is 24”, and site-sizeable linear drains can be adjusted to the needs of any larger space through cutting the lengths down to size or connecting them with bridge pieces and additional drain connections. They are available with the common outlet drain installation, as well as the side outlet option. The horizontal side outlet drain allows for the outlet to be rerouted - for instance, along the top of a slab or under a subfloor - to the existing plumbing.

Installation Options

A key factor in choosing a linear drain is determining the functions it needs to perform, which influences where it should be located and the type of installation.

Wall-to-Wall - With a wall-to-wall linear drain, the channel runs the length of the room. Because the length of the room is not as exact as a standard-cut channel, this is accomplished by linking multiple pieces together. These require a traditional clamping drain body and waterproofing measures, such as hot mopping the shower base.

Against a wall - A popular choice with linear drains is to install them flush against the shower wall. This removes the need for any tiling behind the drain, and water splash from the wall goes directly to the channel. This allows for modern waterproofing techniques and fixed-flange channels with a built-in edge to layer under the waterproofing medium.

Threshold -  Positioning the linear drain at the threshold, or door, helps keep the water inside the shower area. Whether the barrier is a glass door or a raised curb, extending the drain across the entire open area can add an extra level of assurance against overflow. For these arrangements, it’s best to use a wider, grated channel cover so that the channel can catch the necessary amount of water without flooding into the dry area of the room.

Barrier free - When the floor area is level and flat between the intended shower area and the rest of the bathroom, another option is the barrier free installation. This arrangement allows for a tiled floor that is consistent throughout the entire room, rather than requiring the tiles around the shower area to be adjusted in size or pattern around a curb or wall. While the identical tile pattern can be used between the wet and dry areas, the floor should still be pitched toward the drain in the immediate shower area.

Center pitch - With a center pitch drain, the water drops into a square-shaped trough under the flat or tiled cover, rather than a narrow channel. These drains are intended to go in the middle of the shower area and require the floor to be sloped toward it in all directions.

Cover Types

The finished grate covers are designed to catch larger debris and prevent it from making it to the drain, while still allowing for easy water flow into the channel. Some cover types limit the flow rate of water to the drain because of their design, so be sure to choose the cover that will best suit the likely water flow demands on the shower. To ensure easy maintenance, the grates can be lifted out of the channel with a specialized tool, called a key, to provide access to the drain and clear away debris. A removable debris basket covering the drain outlet makes clean up easier and ensures a longer life for your plumbing system.  Regular cleanings every few months can also help keep things flowing smoothly.

Tiled-in - Tile insert channel covers have an inset shelf to install tile patterns on. The drain can virtually disappear into the surrounding tile while still allowing water to slip away into the channel. The tile cover does limit the flow rate, so these are not recommended for high-volume shower areas.

Grated - The grated channel cover can be a traditional grid, or another pattern grid, safe for walking on and installed evenly with the surrounding tile. Some manufacturers offer unique, artistic covers with flat panels and machine-tooled designs engraved for the water to move through.

Floor Slope

Both center pitch drains and linear drains require a gentle ¼” slope per foot, but the difference is in the effective angle that the slope creates.

The floor surrounding a center pitched drain is sloped in four directions, like an inverted triangle, which creates an uneven, almost circular grade across the floor.  For instance, with a 4’ space from the drain grate to the shower wall, there should be a 1” difference in floor height, and when that difference is achieved at four different angles, it creates a funnel effect to guide the water. The ground is not level, and the ¼” pitch becomes more obvious.

The slope around a center pitch drain also requires smaller tiles, which add to the curvature of the floor. It’s best to keep the tile size under 4” square, which limits the colors and patterns available, and in turn limits the creativity of your bathroom design. There’s also a drawback with the smaller size tiles because they require more of the floor to be sealed off by grout. The more grout on the floor, the more opportunity there is for the grout to crack over time. Cracked grout means extra work to regrout and reseal the shower, as well as presents the risk of water damage to the floor below.

With linear drains, the floor is kept flat and has a less noticeable grade toward the drain. The uni-directional slope required for a linear drain helps with more efficient draining, and keeps things safer because you’re walking on a consistent, level surface. Larger tiles can be used to help maintain an even, flat pitch to the floor. Not only is it safer, larger tile allows for a wider variety of tile design choices, and less time spent on grout maintenance in the long run.

An Important Note on Waterproofing Techniques

The bathroom surface must be properly sealed against water and vapor moisture to protect the walls beneath the shower or wet area. Without it, the wallboard can deteriorate or grow dangerous mold and mildew. There are different ways to make sure the shower area is waterproof.

Some contractors and plumbers rely on hot mopping to help insulate the shower area. Hot mopping is a process that involves framing the area to be protected and covering it in a seal of hot asphalt and fiberglass, around the drain. The preslope and tile base are then built up to meet the drain channel edge. Professional hot mopping installation is a safe and effective way of protecting your home.

A common choice is to combine shower pans with sheets of protective membrane and other layered, water-resistant materials that the tile can be grouted to directly. The extra layers of protective rubber, fabricated pre-walls, and membrane sheets limit the amount of moisture that can sneak through to the wall. Modern waterproofing allows the tile to be installed above the preslope, overlapping the drain flange, and locking it in place to add a little extra protection.

Shower pans are another installation option with linear drains. The molded shower trays, or bases, don’t require building a preslope pitch into the bathroom floor, and they provide a pre-shaped curb to help keep the water in. Some products can be tiled directly, offering the same look and feel as any other construction. There are various shapes, colors, and sizes available that can be paired with shower enclosure kits, flashing kits, or traditional waterproof tiling measures to complete the shower area. With linear drain shower pans, the space for the linear drain is pre-cut and ready to install.

The goal of thorough waterproofing techniques is to protect the structure of your home, and your family’s health, by preventing mold or water damage. The best way to ensure a safe tile and drain installation is to carefully follow the manufacturer’s instructions at the time of initial installation. Whenever possible, hire a professional for the task, because it is a complicated process. Even slight imperfections can cause draining issues, and the pros know what to look for, how to handle dents or scratches in a drain channel, or how best to maintain a tight seal on connected drain channels, among other potential snags. When every surface in the shower area - not just the floor - must be pitched toward the drain, the project can get complicated, and the experts know exactly how to handle it.

Why Choose A Linear Drain?

Obviously these drains aren’t for everybody. Converting an existing drain system to a linear drain can be costly and complicated. But there are certainly benefits to consider when making the choice.

1. Design. Sleek and stylish linear drains offer more design freedom when planning the look of your shower. The drains blend into the other visual elements of the shower area, making it all but disappear. Standard drains can draw attention, while linear drains can be covered with decorative channel covers or tiled to match.
2. Layout. Incorporating a linear drain into your shower allows for non-traditional tiling options. Use the same consistent tile size and design throughout the whole room, rather than setting the wet area apart. Linear drains eliminate the need for a shower curb, and without that visual break in the floor, the room will appear larger. You can utilize more of the space.
3. Safety. The gradual, flat slope drains the water away quickly, and the level floor surface can be designed to meet ADA standards for accommodating wheelchairs or other mobility aids. Linear drains are a great solution for anyone considering aging in place updates to their home.
4. Durability. When installed properly, the sturdy channel covers can support weight, and there are no raised edges to trip on.
5. Location. Linear drains can be installed in a bathroom, a garage, or even on an outdoor patio. Whether accomodating a shower, a water feature like a fountain, or a high-use area, the wide channels help collect water and drain it away from anywhere moisture can cause damage. They offer wall-to-wall coverage, with no more puddles.
6. Maintenance. The channel covers on linear drains are easily lifted off with a key tool. A debris shield over the drain can help keep the pipes clean, so everything is designed to be easy. The water flow through the channels does most of the work for you, and you can wipe the channels down if there’s signs of build up.

Linear drains have come a long way from their humble industrial beginnings. Now they can be flashy and stylish, or they can hide in the tile floor. They are a unique and luxurious alternative to the exposed center drain. When updating your bathroom shower area, choose wisely, and enjoy your custom shower for years to come.