Moss in Detail: a Linear Drain Shower


The walk in shower, with linear drain, is a key component of most of our recent bathroom designs.  By popular demand, and because genuinely like them, we find that we’re drawing linear shower drains into walk-in showers for nearly every project.  Today we explore how they work … and why we like them so much.

Context: A Modern Bathroom

You’ll likely never see moss recommend one of those tragic tub/shower combo numbers that plague the contemporary residential bathroom.  Neither fish nor foul, they make for inconvenient showers and uncomfortable baths … why bother?  Our client base seems to agree – when we address a bathroom area we usually end up turn guest bathrooms into shower-only units and if the master bathroom needs a tub – we’ll keep it separate from the shower.


We like to minimize the transition from shower to the adjacent space.  If we can get away with re-contouring the floor, we’ll do a zero threshold – its convenient and more accessible ,to boot!.  If we are replacing existing plumbing, we may need a small step transition.  We prefer an unfussy glass wall, possibly with a simple glass swing door to enclose the shower area – its relatively easy to swipe clean and expands the visual area of the bathroom.  And for the shower floor – we love a linear drain.

Why Linear Drains?

We have a few different reasons to love these unconventional shower drains.

  • Aesthetic – they are sleek and slim, they pull the eye along and fit in nicely with a lot of different shower floor surfaces
  • Utilitarian – linear drains are easy to keep clean and draining smoothly.  Who doesn’t love an easy to clean drain?
  • Practical – in many of our remodel projects we are pulling out an old tub and replacing it with a shower.  That may sound like a simple process but it can often require some creative plumbing.  Linear drains allow us to be more flexible with drain placement and keep a lower profile (less of a step up) for the new shower that’s going in.

That’s a pretty clear triple threat.

The Anatomy of a Linear Drain

Here’s a little diagram of the drain area of a walk in shower supplied by Infinity Drains.  We like this brand and have specified it several times.  We’ve also used the Quartz linear drain by ACO.

infinity linear drain detail

Effectively a linear drain just a longer wider catch area that fits onto the top of the type of standard floor drain that is under every shower and bath.  But that length provides a flexibility that we find very useful.  Here’s how:

Ever Wonder What’s Under Your Tub?

Here are a series of images of a project that’s still underway (no final photos) where we replaced an existing tub unit with a walk in shower.

This remodel is taking place in a loft with concrete floors so there is even less room for moving the plumbing around than usual.  If we’d wanted to use a conventional drain with this new shower, the plumber estimated that we’d need an additional eight inches of height for all the collar connections (and that doesn’t even account for the fact that the rest of the shower floor has to slope DOWN to the drain.  Using a linear drain meant we were able to keep that step up to about 6 inches at the high end and slope it down to only 2″ above the floor outside the shower.

First, the original tub in situ (also a basic toilet-seat-up – names withheld to protect the innocent).

linear drain install_tub

After demolition, the former tub drain projects from the concrete floor of the unit.  We DID NOT want to move this drain for fear of incurring a lot of extra cost and possibly affecting neighboring units.

linear drain install_drain

Once the waterproof membrane wrapped around the entire base area, the channel for the drain was fitted into the existing drain connection.  The fact that the drain can sit anywhere along that horizontal length meant that we weren’t limited to the exact width of the previous tub unit – we were able to make the new shower slightly wider.

linear drain install_waterproof membrane

Finally, the sloped shower floor draining to the new linear drain at 1/4 inch per foot. The shower walls were prepared with a thick coat of waterproof paint but the final tiles hadn’t been selected at this point.  A handful of options are leaning against the walls.

linear drain install_tile

Linear Drain in the Wild (in the Bathroom)

Here is the final installed linear drain at the West Loop Loft.  For this project, the continuous shower floor with trench drain was refined from its original design – that task was made easier since moss was both general contractor and architect.  Here’s the original sketch – with the new concrete floor continuing into the shower (at a 1/4″ per foot slope).

racine shower detail

From there, we went through several iterations: the first idea – river rock embedded in aggregate – was superseded by a plan to use commercial stone tile product (hand modified to include dark and mid toned rocks along with the original white).  In each version, the floor  is continuous with a slight slope to the side trench drain.

trench drain custom shower floor

And here is the whole shower, with a side view of the adjacent bath.

racine shower bath composite

Read more about the entire West Loop Loft Project here.  Long Live the Linear Drain.