Description: Expansion joints at roof edges usually occur where an independently supported roof meets a wall. This condition is often the result of a new structure adjacent to an existing one.
A continuous wood curb is required along the roof perimeter. It should extend at least 10" above the adjacent roof. The top surface of the curbs should be sloped away from the joint, to shed condensation and moisture onto the roof. Insulation is often used in the expansion space, but is left out of the details for clarity.
11.2A. Expansion Joint Between Flat Roof and Wall
Copper base flashing is double-folded and nailed to the top surface of the curb which is cut to a slope of 3" per foot. Its lower edge is held by a continuous edge strip. Its upper edge is folded over, and long enough to accommodate maximum movement. Copper counterflashing is folded into this edge. The upper edge of the counterflashing is held by a copper receiver, which is set in the brick joints. If the wall is an existing one, the mortar joint is raked to a depth of 1" and the copper receiver is inserted, wedged, and sealed.Download CAD File
The curb shown is double width to provide a broad enough surface for the expansion and contraction in the copper joint and to allow for the nailing of the base. Depending on the width of the expansion joint, it may be necessary to widen the curb further.
11.2B. Expansion Joint Between Flat Roof and Wall
A continuous lower copper base flashing is nailed to the top surface of the wood curb. Its lower edge is locked onto a continuous edge strip. The lower base flashing is formed into a lock large enough to accommodate the maximum expansion, as shown. the upper copper base flashing is loose locked onto the edge strip. Its upper edge is held to the wall by cleats, spaced no more than 12" O.C. Copper counterflashing laps the upper base flashing a minimum of 4". It is secured to the wall in a reglet or in a joint in masonry, and sealed.Download CAD File
11.2C. Expansion Joint at Standing Seam Shed Roof
This condition shows the expansion joint between the head of an independently supported shed roof and a wall. Three alternate details are shown.Download CAD File
The roofing pans are terminated several inches below the top of the roof. Each pan is secured to the roof substrate with 2 cleats. A continuous copper lock strip is soldered to the pans at least 4" below the pan's upper edge. The standing seams are laid flat to this point. Copper base flashing is locked into the lock strip. The upper edge of the base flashing is formed into a loose lock large enough to accommodate the maximum movement and fastened with cleats at 12" O.C. Copper counterflashing is folded into the loose lock.
- Alternate 1
The copper base flashing's upper edge is formed into a double fold large enough to accommodate the maximum movement. It is fastened with cleats spaced a maximum of 12" O.C. The copper counterflashing is folded and loose locked into the double fold. It extends at least 8" up the wall, where it is inserted into a reglet or in the joint between masonry courses. Download CAD File
- Alternate 2
The copper base flashing's upper edge is formed into a lock and fastened with cleats spaced a maximum of 12" O.C. A continuous copper lock strip is soldered to the base flashing and receives the end of the counterflashing. Download CAD File
- Alternate 3
The copper base flashing's upper edge is formed into a "bread pan". Its upper edge is large enough to accommodate the maximum movement. The copper counterflashing is loose locked into this edge. Download CAD File
If the design is for long pan, then expansion of the roof pan relative to the base flashing must also be accommodated at the lock strip and cleat. See Roofing Systems - Long Pan.