Thanks for asking about this lovely waterfront kitchen. We do not actually join the different countertops in situations where two or more materials are used. Rather, we meet the two surfaces, varying their heights just a bit. In this case, the wood is about 3/8" lower than the granite. Where the surfaces meet, there is a bead of clear silicone to seal whatever tiny gap there might be between the two. The granite is templated on-site once the base cabinets are set and level. SInce the tops come from different vendors, a second measure could take place after the granite was installed to ensure a tight fit between it and the wood.