Vertical Applications: Solid Surface Shower Walls, Wainscoting, Interior/Exterior Wall Cladding

Vertical Applications: Solid Surface Shower Walls, Wainscoting, Interior/Exterior Wall Cladding, etc.

The installation process for solid surface vertical applications, such as shower walls, tub surrounds, wainscoting and wall cladding are procedurally very similar, therefore we’ll address them as a group.

Dry and Wet Locations

To begin with, make sure the wall surface that the solid surface material will be adhered to is sound and made of the correct materials for the intended use. For dry locations, the supporting wall material can be a sound tile or plaster surface, MDF particle board, drywall/sheetrock, moisture-resistant plywood, or cement backer board.

For wet locations that are above grade (in a portion of a building that is above ground), amend the materials list above as follows: do not use MDF, use marine-grade plywood and use moisture resistant drywall/sheetrock. If the wall you are installing on is below grade (in a portion of the building that is below ground, like in a basement), it is not recommended to use solid surface due to moisture seepage into the wall.

Before fastening the solid surface sheets in place, fit, scribe and cut, or sand the edges if need be, to ensure the sheets fit correctly. If two or more sheets need to be seamlessly joined, mirror cut and seam them together with a solid surface backer board glued in place, as described in the earlier section on seaming. The wall surface will need to be notched to accommodate the thickness of the backer board since it is on the back facing surface of the seamed sheets. Prepare the edges before seaming by using a tongue and groove router bit set or a wavy bit set. This will help insure the sheets are level with each other and minimize the amount of sanding required to hide the seam location.

Fasten the solid surface sheets to the wall by placing 100% silicone sealant around the entire perimeter of the sheet. For the interior of the sheet, use thumb size daubs of silicone every 8-12 inches in a matrix pattern. Alternatively, you can also run vertical beads of silicone every 8 inches. However, if the wall surface is uneven, the tall daubes of silicone are generally a better choice since they will span the gap from the wall to the back of the solid surface sheet.

You can use large blobs of hot melt glue to hold the sheets in their final position while the silicone cures. To do this, pull the sides or edges away from the wall just enough to place the large blobs of hot melt glue, and then press and hold in place until it solidifies. You can also use braces to hold the sheets correctly in place and forgo using the hot melt glue.

Flat Wall Treatments

For flat wall treatments, like shower walls, tub surrounds, wainscoting and wall cladding, there are three popular ways to deal with the flat seams where two panels come together. The first is called a Batten strip. It is usually an inch or more wide with eased edges (edges that are rounded) and is held with silicone over the 1/8” seam, which is also filled with silicone. A second option is to silicone the seam and then leave it uncovered. A third option is to create a “hard seam” by gluing the sheets together with solid surface adhesive. If constructed well, this seam will not be visible.

When you are working with large expanses of solid surface, the length of sheets that can be “hard seamed” is limited. This distance is limited and determined by the variation of temperature that exists. For example, if the temperature varies, from high to low, by 40 degrees, then the maximum length the seamed surface can be is 18 feet. However, if the temperature only varies by 10 degrees, then the length can increase to 72 feet. Therefore, a silicone joint that allows for expansion or contraction needs to be placed every 18 feet or 72 feet, respectively. You can refer to DuPont’s technical bulletin, “Dupont Surfaces: Dupont Corian Solid Surface Commercial Interior Surface Installation” for more details and information.


When working within an inside corner, it is recommended to use a silicone soft seam where the sheets come together. You can then either leave the seam like this, or use one of several decorative trim covering options to make it more aesthetically pleasing. These trim pieces range from a triangular strip, to a coved strip affixed with silicone over the corner. Hard seaming is also an option, but requires special fabrication tools or thermoforming. Outside corners can be either hard or soft seamed. These treatments are explained with diagrams in the Dupont Surfaces, technical bulletin.

Showers and Tubs

When working with showers and tubs, install the back wall first and leave 1/8” on all sides for expansion. Scribe and cut the sidewalls and cut any needed holes with a roto-zip tool, router or hole saw. After you attach the sidewalls and they are set, wipe with denatured alcohol in the places where silicone will be applied. Apply silicone from the bottom up and remove any excess with denatured alcohol after it sets. Wait to apply silicone until after the denatured silicone has evaporated.

Wainscoting and Wall Cladding

When using solid surface for wainscoting (paneling) and wall cladding, leave a 1/8” gap at top and bottom and inside corners and apply silicone around the edges to allow for expansion. Use top to bottom beads of panel adhesive so that the central areas of the panel are allowed to remain flexible.

Make sure to use a router for cutting the solid surface material and not a saw. A router creates a smooth edge, whereas a saw creates a fractured edge. Ultimately, using a saw can create fractures or cracks that can extend into the material and create larger cracks.

When attaching solid surface baseboard or chair rail moldings apply silicone in continuous beads near the top and bottom of each strip, which allows for expansion and contraction. Apply hot melt glue in dabs to hold the molding in place while the silicone is setting.

Remember: Solid surface expands and contracts a fair amount, therefore it should not be adhered using a hard seam adhesive or it will break itself loose.