How to Replace a Foam Gasket for a Glass Cooktop

Close the gas valve under the cooktop if the cooktop is a gas model. Unplug the electric cord (both electric and gas cooktops have power cords).

Use an adjustable wrench to unscrew the coupler on the gas hose between the valve and the cooktop.

Use the wrench to remove the bolts and washers on the underside of the counter where the hardware connects to the cooktop. Slide off the metal bar held in place by the bolts under the counter.

Lift the front edge of the cooktop with a putty knife to break the seal. Pull up and remove the appliance from the rectangular space on the countertop. Set the cooktop to one side on the counter.

Peel up the old foam gasket, using the putty knife if needed.

Scrub the countertop with a sponge and liquid degreaser detergent to remove grease and residual glue from the old gasket. Dry the area with paper towels.

Remove the protective tape on the adhesive side of the new gasket and press the foam carefully around the perimeter of the installation opening. Work out bubbles and puckering in the gasket with your fingertips.

Lower the cooktop back into the opening, ensuring that the power cord and the gas hose, if applicable, hang below the unit inside the cabinets. Press firmly around the edges of the cooktop to seat it on the foam gasket.

Replace the metal bars under the countertop with the bolts and washers, securing the hardware with the nut drive to lock the cooktop in place.

Coat the valve threads on the gas line with gas-pipe sealant, and reconnect the cooktop hose to the valve. Tighten with the wrench. Skip this step if hooking up an electric cooktop.

Plug the power cord into an outlet.