Abstract: An enclosure assembly for use with mechanical penetrations through a roof including a plurality of structural sections. Each structural section has a vertical portion, including a first end and a second end, and a horizontal portion. Each first end includes projections and each second end includes receptacles, wherein each projection is adapted to sealingly engage with a receptacle of an adjacent structural section. Each projection is inserted into a cooperatively aligned receptacle of an adjacent structural section to form a polygonal-shaped assembly having a plurality of connections and defining a cavity. The projections may be hook-shaped and the receptacles may be rectangular-shaped. The resulting cavity is shaped to contain a sealing material suitable to sealingly enclose a mechanical penetration and a portion of the exterior roof surface within the cavity.