Wall 1B Interruptions

In this retrofit wall assembly, the water control layer is in a familiar position relative to the sheathing of the wall but at an unfamiliar position relative to the rain shedding or cladding layer. All of the flashing details must connect to the water control layer at the wall sheathing and behind the insulating sheathing. As this water control layer is also the air control layer, particular attention is needed to maintain the airflow control through flashings.

Wall 1B Porch and Deck Connections

Porch Roof or Ceiling Connection to Wall 1B — Porch Roof/Ceiling Connection to Wall 1B

Curb of insulating sheathing is provided to allow access to step flashing during re- roofing of porch roof at a future date.

Deck Connection in Field of Wall 1B

Curb of insulating sheathing is provided to allow access to the deck structure for future maintenance.

Deck Connection to Base of Wall 1B

Curb of insulating sheathing is provided to allow access to the deck structure for future maintenance.

Wall 1B Windows and Doors

There are two kinds of windows-windows that leak, windows that will leak. This can be said of doors as well. Because of this, it is necessary to flash the window or door opening such that it is a drained opening - when the window or door leaks, water is controlled and the wall system is protected. Sill pan flashing, jamb flashing and head flashing form the water control system for the opening. The sill pan flashing is especially tricky because it must conform to the three dimensional corner configuration at the intersection of the sill and jamb of the opening. Also window and door frames tend to have sharp corners - if the sill pan flashing is not tight to the corner of the opening, the window or door frame could cause a tear in the flashing precisely at the most vulnerable location of the opening. For this reason, one should not attempt to provide pan flashing with flat peel-and-stick membranes. The corners of the sill pan flashing should be executed with pre-manufactured corner flashing, liquid-applied flashing membrane, or flexible flashing membrane.

When existing windows are retained, there may be a compromise to the water management of the wall. Even today (sadly) it is not common practice to install pan flashing in window openings. Older wood windows typically incorporate a continuous wood sill that is sloped to the outside and includes a drip reglet on the underside of the front edge. If properly maintained, such a wood sill may serve to direct water that leaks into the window (e.g. under or around window sash) back to the exterior. Where an existing window is retained within a wall to be retrofitted with insulating sheathing and new cladding, the details around the window should facilitate a minimally disruptive replacement of the window at some point in the future.