Solid-surface countertops are a popular part of today’s kitchen remodels: The look is sleek and seamless; the color and design options are plentiful. Practicality only adds to their appeal-most solid countertops stand up to stains, scratches, sunlight and heat.
However, installation of solid-surface countertops requires skill, and most countertop manufacturers and suppliers recommend installation by a certified installer. Pay careful attention to these problem areas to ensure your customers are satisfied with their countertops long after initial installation.
Problem: Improper support
A support structure that is flimsy, out of level or doesn’t allow for proper ventilation can cause cracking and seam separation.
Solid-surface countertops must be supported on a strong continuous perimeter support frame that will keep it flat and level. The frame must be able to provide support at inside corners and across long spans.
Don’t use solid underlayment for support, as it can cause heat build-up when appliances such as portable frying pans are placed on the counter.
Only install countertops directly onto cabinets
- if they are strongly fixed together
- all tops are in the same plane
- gaps are filled in
- there is front-to-back support for cutouts.
The countertop must also be high enough to allow drawers and doors to clear the front edge. The support structure should allow free air circulation beneath the counter. Add wooden shims to the cabinet base top edges if necessary to level the surface. This ensures the countertop support stays flat and true against the back edge of the countertop. Use silicone sealant to attach the countertop to the cabinets. Place dabs of silicone every 6 inches-not in a continuous bead. This allows for expansion and contraction from temperature changes.
Problem: Seam separation
Joint adhesive creates a bond between two sections of countertop. When the seam isn’t supported, adhesive can leak from the seam causing a weak spot that may eventually lead to seam separation.
Reinforce all seams with a 2- to 3-inch strip of solid-surface material cut and glued under the seam in the deck. The strip must go the full length of the seam, and both surfaces should be completely covered in joint adhesive. Be sure the strip is free of chips or damage.
Problem: Cooktop cracks
As a cooktop heats, it expands, transferring heat to the surrounding countertop. Overheating can cause the countertop to crack. Improperly cutting and sanding the edges can also result in cracking.
The cutout for a drop-in range should be at least 1/8-inch larger than the appliance on all sides to allow for expansion. Use a router saw guided by a template to make the cut. Round the edges to a radius of at least 1/16-inch and sand all surfaces smooth. Be sure the cooktop is installed correctly with aluminum tape covering all solid-surfaces under the entire flange, including the vertical edges of the cutout. The tape helps distribute the heat of the cooktop to the space below rather than the surrounding countertop.
Problem: Inside corner cracks
Inside corners on L- and U-shaped countertops are another problem area. The square cut produces a stress joint that can result in breakage.
Inside corners should have at least a ½-inch radius. The matched joint must also be at least 3 inches from the inside corner. Use a hardboard template and router with a guide bushing and straight cutting bit or top bearing bit to cut this radius.
- Make a trial cut on a scrap piece of material to check the depth and shape of the router cut before making the edge cut on finished work.
- Don’t rush the cut. Rushing creates a rougher cut that requires more finishing work.
- Use manufacturer-recommended tools and blades to ensure clean cuts. Small fractures can lead to cracking.
—By J. Costin
|Router Task||Router Power||Router Bit|
|General PurposeEdge and seam trimming, cutouts||2+ hp||3/8-inch (10mm) carbide-tipped single flute with ½-inch (13mm) shank½-inch (13mm) carbide-tipped double flute|
|Heavy DutyBulk cutouts, banjo cuts, coving||3+ hp||½-inch (13mm) carbide-tipped single flute with ½-inch (13mm) shank polycrystalline diamond bit|
|DetailEdge treatment||1½ hp||Carbide-tipped decorative bit with ½-inch (13mm) shank|
Source: Corian fabrication guide