A frameless shower has by design small gaps in the seams of the glass panels and around the door. Gaps exist because the unit lacks the thick metal frames found in traditional framed shower products. The custom nature of a frameless shower also lends itself to less forgiving tolerances than prefabricated framed units. Though a frameless shower should never be considered a completely water tight enclosure, there are a few techniques that can be followed to minimize the amount of moisture that leaves the shower.
One technique for minimizing the amount of water that escapes through the seams of a frameless unit is to utilize polycarbonate pieces that create seals between panels or between the glass and surrounding enclosure walls.
A standard single door (less than 30″ wide and 78″ high) has a 3/16″ gap between the wall and the door glass where the door is hinged to the wall. On the handle side of the door, a 3/16″ gap between the door and the wall is recommended in order for the door to swing properly. Finally, a 7/16″ gap is left between the sill and the bottom of the door glass.
In order to prevent water from leaking out underneath the door, a polycarbonate door sweep is attached to the bottom of the glass. The sweep directs water back into the shower and acts as weather-stripping underneath the door.
Gaps on either side of the door remain. Unless your shower head is pointed directly at the gaps though, an extremely minimal amount of water, if any, will escape. The potential for minimal leakage is the trade-off between frameless heavy glass showers and the less custom thin glass framed units.
When your shower configuration includes a door and a panel, an open space exists between the door and the panel. This space can be virtually eliminated by using a strike. When the door is closed, it rests against the strike that is attached to the panel, sealing the gap.
There are a multitude of other polycarbonate pieces that can be employed in certain situations to seal gaps. See your local glass company for non standard needs.
In addition to using polycarbonate seals, constructing your opening so that the walls are plumb, level, and square helps to ensure that all of the enclosure pieces fit together tighter.
A third and extremely critical technique to preventing water leakage is to eliminate any flat surfaces in the shower where water can pool. This is done by creating slopes with the tile so that water runs back into the shower.
There are two areas where the tile should be installed with a 5 degree slope. The first area is the seat (if applicable) that the return panel glass sits on. The return panel is typically where the shower head is directly pointed. If your enclosure features a seat, water will naturally pool up as it splashes off the return panel. If your tile work is done correctly, you shouldn’t have any major issues. Poor tile work however can easily be exploited by sitting water seeping through grout joints. To prevent water from pooling up on the seat, make sure the seat tile is gently sloped back into the shower at approximately 5 degrees.
The second area that water can exploit if not properly constructed is the sill or curb. The sill is typically a single piece of marble that spans the opening of the shower along the bottom. It usually sits a few inches off the ground and is the threshold you step over every time you get in and out of the shower.
As water hits the door or inline panel it rolls down the glass. The door sweep has a sloped fin that guides the water away from the door. Rolling off the sweep fin, the water hits the sill. A shower door sill that is properly constructed will be sloped approximately 5 degrees so that water rolls off the door, off the sweep fin, down the sill, and back into the shower.
If the sill is not sloped, water will collect and pressure from the cascading moisture above will slowly force it to find an exit around the door. Even the smallest gaps in the enclosure are large enough for water to find its way out and into the surrounding bathroom. The amount of water escaping on a per use basis may not be very noticeable. Over time however the continual presence of water outside the shower can lead to noticeable damage on wood and other surfaces.
You should be especially careful with fiberglass shower pans. While there is no problem installing a frameless shower door in a tiled opening that uses a fiberglass pan as the base, the online specs for these products do not mention whether the sill is sloped at all. If not sloped, water has the potential to collect and increase the leakage of your frameless shower.