An Insulated Roof Parapet

Passive House consultant Cramer Silkworth (left), architect James Wagman (center), and remodeler Jose Maldonado (right) meet on the roof of a brownstone on Prospect Place in Brooklyn, New York, to discuss details of the exterior insulated finish system (EIFS) cladding for a new addition under construction at the rear of the building in April, 2014.

To keep the mass of the city-required noncombustible masonry wall for the townhouse addition inside the thermal envelope of the building, architect James Wagman and Passive House consultant Cramer Silkworth specified this insulated masonry detail. An exterior insulated finish system (EIFS) cladding on the masonry wall integrates into a four-inch buildup of foil-faced high-density polyurethane insulation on the roof deck, minimizing any thermal bridging through the wall, the roof, or the wall-to-roof joint.

Remodeling contractor Jose Maldonado, owner of J’s Custom Contracting in Brooklyn, New York, points out the elements of a Sto exterior insulation finish system (EIFS) cladding for the masonry walls. The cladding system consists of a 4-inch layer of expanded polystyrene (EPS) insulation, with a galvanized steel reinforcing mesh, a cementitious base coat, and a colored cement stucco top coat.

Adhesive caulk is applied to the face of a 2x4 nailer before attaching it to the poured concrete cap of the masonry parapet wall.

A powder-actuated fastener is used to drive hardened masonry nails to attach a wood nailer to the concrete cap of a masonry parapet wall.

Foam is measured and marked in place before cutting and installing it onto the masonry parapet wall.

EPS foam is cut with a handsaw before fitting the foam into place on the top cap of a masonry parapet wall.

Cement mortar is applied to the poured concrete cap of the reinforced masonry parapet wall before placing the insulating foam component of an EIFS cladding for the parapet.

A carpenter from J’s Custom Contracting uses the toothed edge of a mortar trowel to scratch grooves into the underside of a piece of 4-inch EPS foam, to improve adhesion of the cementitious mortar used to attach the foam to the masonry parapet wall as part of a continuous insulation and finish system for the building’s masonry bearing wall and parapet wall. The foam insulation on the parapet wall will tie into the polyurethane insulation on the building’s roof deck, providing a continuous thermal control layer that keeps the building’s wall and roof structural mass within the insulated plane of the building.

The underside of a piece of 4-inch EPS foam is buttered with cementitious mortar …

… before being set onto the poured concrete cap of a reinforced masonry parapet wall.

A carpenter from J’s Custom Contracting applies mortar to the joints between EPS foam insulation pieces for the exterior insulation finish system (EIFS) cladding on the masonry parapet.

The completed exterior insulation finish system (EIFS) cladding sits ready for additional roofing and flashing details.

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