Abstract: A vapor barrier and cavity seal includes a head attached to a body. The seal closes a cavity between an interior framed wall and an exterior wall or veneer of a building. The head includes a rounded surface opposite the body and has a width that is greater than the width of the cavity and is disposed to bridge across the entire cavity. The body is square or rectangular in shape to easily fit between the interior and exterior walls within the cavity. The seal may include a foam polyethylene or is formed from a closed cell, soft, flexible non-gassing rod of material that is easily extruded. It may be provided in various dimensions and densities depending on the cavity or expansion joint size required or needed to be filled. Typically, the seal may be used on door and/or window jambs where a 1? or 2? gap is required between a brick veneer and framing when a vapor barrier is specified in construction specifications.