Heat emanating from cooktops can create an expansion and contraction issue with your solid surface countertop. This is especially true at the corners of the cooktop cutout opening.
Most cooktops come with a pattern to indicate the size of the opening needed. However, make sure to allow for ¼” space around the edge of the actual glass range top when you cut the opening (not including the decorative finish ring) to account for potential expansion and contraction. Be especially careful not to cut away too much material at the corners .
The cutout can be made with a jigsaw, but using the router and template method is preferred. If you use a jigsaw it’s essential to remove all the tooth marks left by the blade with sandpaper. Otherwise, the tooth mark impressions can create stress points and become an initiation point for cracking.
The edges of the opening should be taped with aluminum-backed insulated tape to help with expansion caused by heat from the cooktop. Tape the entire inside edge of the cook top opening with 9 mil heat reflective tape. Apply two layers of aluminum tape in the corners and do not wrap the tape under the surface (See Figure 16.)
Figure 16: Cooktop Layout and Taping
All four corners should be reinforced with 5” square blocks that have rounded edges. The inside corners of the countertop must have a minimum ¼” radius, as seen in Figure 17. All of these steps are designed to prevent cracking of the countertop due to repeated heating and cooling associated with use of the range top. Lastly, trim the aluminum tape so that it is not visible from the top surface.