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Frameless Shower Installation

- Continued Critical accuracy. The most important aspect of installing a frameless enclosure is getting the measurement for the opening correct. You can be the best installer in the world, but if the initial measurements aren't right, the unit won't work. Kathy takes about two hours to produce an on-site drawing, referring to a precise angle finder, a 4-foot level, a plumb bob, and a square to record all dimensions, angles, and transitions, and all plumb-and-level conditions. The basic drawing is usually nothing fancier than a shop sketch for our own use, although, occasionally, a client will want a more elaborate, finished perspective drawing as a visual aid. Accuracy is critical; any error will make for a very unpleasant, perhaps impossible, installation later on. If the wall is out of plumb, the glass must be fabricated accordingly. Metal U-channels or clamps (Figure 3) hold the stationary panels at the wall, so we allow for the metal thickness and make a small deduction for clearance and adjustment. The fabricator cuts the glass to our exact dimensions, but edge-polishing usually knocks off another 1/16 inch, so we might get a touch more play than indicated.


Figure 3. Wall-mount hinges and clamps or a metal U-channel secure the glass to the wall, ceiling, and floor. Deductions must be made from the overall dimensions to accommodate hardware clearances (inset). A glass corner clamp requires 3/4-inch-diameter mounting holes in the adjacent panels. Glass corners may be mitered, butted, or overlapped.

Tempered glass.

The glass in a frameless enclosure can be either 3/8-inch- or 1/2-inch-thick tempered panels. Tempered glass is nothing more than common float glass that's been raised close to the melting point — around 1,400°F — then quickly cooled by quenching, which alters its molecular composition. Ordinary plate glass, when broken, produces heavy, sharp, potentially lethal shards. Tempered glass, on the other hand, is seven to ten times stronger than plate glass, and very difficult to break — in fact, you can drive a pickup truck on a panel without breaking it (we've done it). Peculiarly, in spite of its strength, the corners and edges are very touchy. If you so much as nick the corner of a piece of tempered glass, it could explode, but only into thousands of small, lightweight granules that are unlikely to cause injury. This is why building codes require tempered glass in all shower enclosures, among other locations. It's also why we're extremely careful not to allow any metal or tile to come in contact with the edge of the glass. Hinge decisions. There are a few different ways to hinge a glass door. The size and weight of the door determines some of the options. For example, 3/8-inch glass weighs 5 pounds per square foot, so if the plan specifies a 32-inch-wide by 80-inch-high door, the weight would be approximately 88.9 pounds. The maximum weight allowable for a door using two Geneva hinges is 80 pounds, so we would need to add a third hinge or adjust the door dimensions. If we are working with a header and the door is not wall-mounted, we use top and bottom pivot hinges. Both hinge types have a detent device that aligns the door in the closed position.

Data forms.

With all of the final measurements established, we transfer the data for each panel onto preprinted template forms that represent the basic panel shapes and show all dimensions, holes, hinge cut-outs, and miters. Our glass manufacturer, Solar Seal (55 Bristol Dr., So. Easton, MA 02375; 508/238-0112; ), which provides us with high-quality product and fabrication — important if you want your final product to be perfect — works from the information we provide on the template drawings. All of the cutting, shaping, and polishing is done before the glass is tempered. After tempering, no modifications are possible. Delivery time for the finished glass panels normally takes three to six weeks. We order all of our header and channel extrusions in stock lengths, and cut them to size on the job site. The extrusions are available in all kinds of finishes, including solid nickel, brass, stainless steel, and even gold plate. Most of these are easily cut by a power miter saw equipped with a good quality triple-chip-grind carbide-tooth blade.


The first installation step is to establish a layout line on the sill, walls, and buttress wall. A 2-inch-wide strip of masking tape, applied first, provides a legible base for marking that's easy to remove later (Figure 4). We transfer our glass dimensions and any bisecting points to the tape from our worksheet, and double-check all of the angles.


Figure 4. Masking tape provides a legible base for marking the layout line, locating transitions, hardware, and termination points, as well as quick line removal. Clear plastic setting blocks are positioned over the countersunk screw heads in the U-channel to protect the vulnerable edge of the tempered glass panel from contact with the metal and tiles.

Next, we cut and fasten the U-channels or clamps. To make sure that the screw heads don't project and contact the edge of the glass, we countersink the holes in the channel. A bead of silicone on the underside of the U-channel seals and helps to bond it to the tile surface. We install plastic wall anchors in the tile to capture the screws, and use a razor blade to slice the anchor flange off flush with the surface to eliminate any gap behind the channel.Likewise, a quick touch with the countersink bit cuts away the burr from the backside of the screw holes in the channel.