Window Head Flashing and Sealant at a Punched Opening
On a low-rise EIFS building, you are inspecting a punched window opening. The window unit is set with a 1/2 in. (13 mm) reveal around the frame. At the head, the WRB is lapped over the window's integral head flange, but the flashing tape at the head is applied over the WRB rather than under it, and the tape does not extend past the jamb corners. The sill has a sloped sill pan, but the pan's end dams are absent and the sealant joint at the sill is a bead of caulk applied over the EIFS finish rather than a backer-rod joint. The installer says the system is 'drained and back-ventilated' so flashing details are less critical. The specification calls for a shingle-lap sequence and a sealed, backer-rod sealant joint at the perimeter.
1. Evaluate the head flashing tape sequence and the missing jamb-corner extensions.
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The head detail is installed in the wrong sequence. In a proper shingle-lap assembly, water must always be directed onto the layer below, so the WRB above the opening should lap over the head flashing, not the reverse. Applying the flashing tape over the WRB at the head can trap water behind the tape and direct it into the wall rather than out. The tape must also extend beyond the jamb corners and be integrated with the jamb flashing so the corners are continuous; stopping short of the corners leaves a gap at the most vulnerable point. Require removal and reinstallation in the correct shingle-lap order: sill pan first, then jamb flashing, then head flashing lapping over the jamb flashing, with the WRB lapping over the head flashing, and all tape extending past corners. The 'drained and back-ventilated' argument does not excuse incorrect flashing; drainage depends on the flashing directing water to the drainage plane and out through weep provisions.
2. What is your finding on the sill pan end dams and the sealant joint?
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Both are nonconforming. A sloped sill pan without end dams allows water that reaches the pan to run off the ends into the wall cavity instead of being directed to the exterior weep path; end dams are required at the jambs to contain and redirect water. The sealant at the sill is also wrong: a caulk bead applied over the EIFS finish bonds to the finish rather than bridging the joint between the window frame and the EIFS substrate, and without a backer rod the joint cannot accommodate movement and will fail. The specification requires a backer-rod sealant joint at the perimeter, so the joint must be prepared with backer rod at the correct depth and a sealant compatible with both the frame and the EIFS, tooled to the specified profile. Document both deficiencies, require correction, and re-inspect the sill and perimeter joints before sign-off.