Granite countertops can be installed in a variety of ways, depending on whether you are working with tiles versus slabs, in addition to the specifications of the slabs and tiles. One of the most expensive types of material you can install in your home, granite countertops are normally installed with one of several different types of glue, depending on the type of installation involved.
Epoxy glue is the most common type of glue used in granite installations, as it is one of the few types of adhesives that can provide a bond that is as strong as the stone itself. A complex blend of resins and hardeners, epoxy glue can be used for the installation of the slabs, as well as the glue used to join two pieces together, such as with two slabs for more thickness, or where two slabs butt up against each other.
Tile mastic is an all-purpose type of glue that can be used with natural stone installations in limited circumstances. While travertine and tumbled marble are softer stones that will soak up the resins and other materials from the mastic, potentially staining the stone, granite is hard enough that the byproducts never have a chance to penetrate beyond the bond. While it can be used to install slabs, it is most commonly used with tile applications.
General Adhesive Glue
All-purpose construction adhesive glue can be used for granite slab installations, although it is generally only used on the bottom layer of the slab to adhere the slab to the plywood decking for the countertop. It cannot be used to bond two pieces of granite together because it does not cure as hard as the granite, and there are also issues with moisture entrapment and the adhesive never drying out.
For caulking joints between transitional surfaces such as where the backsplash meets the countertop or where the countertop material meets a wall, you can use silicone caulk to fill the joint with a clear layer of filler compound. While it is generally only used for joint filling, there are also specialty silicones designed to work as adhesives with granite.