A method of establishing a seal between a casket vault lid and a casket vault base comprises the steps of positioning a gasket between confronting generally horizontal surfaces of the lid and base, positioning a base engagement member of a clamping assembly in a recess in the base, positioning a lid engagement member of the clamping assembly in a recess in the lid, and operating the clamping assembly so as to draw the base engagement member and the lid engagement member toward one another to thereby compress the gasket between the confronting generally horizontal surfaces of the lid and base.