65- 407 C.M.R. ch. 400, § 6
A continuous air barrier shall be installed over the inside face of framing in ceilings which face an outdoor or unheated space, and over either the inside or outside face of framing in walls which face an outdoor or unheated space. The ceiling and wall barriers must be sealed to each other.
Gaps between the rough and finish frames around windows and doors, joints between walls and foundations, all penetrations through the infiltration barrier, such as, but not limited to, those for plumbing electrical conduits, wires or boxes, and ducts, shall be sealed with permanent tape, caulk, sealant, or gaskets.
All walls, ceilings, and floors that separate different dwelling units, or sleeping rooms designed to be occupied by residents from different families shall be sealed against air movement from one unit to another. Air barrier material shall be continuous. All penetrations through the air barrier separating dwelling units shall be sealed with permanent tape, caulk, sealant, or gaskets.
65- 407 C.M.R. ch. 400, § 6