1. OSB Backing: Ensure the recessed opening is entirely wrapped with solid backing and that the shelf has a minimum slope of 1" per foot.
2. Shelf Flashing: Apply self-adhered flashing lapped shingle-style over the entire shelf. At least 2" of flashing (with the release paper intact) should extend out past the front edge. This will later be adhered over the building paper.
3. Shelf Flashing Edges: Use flexible flashing to cover the outside corners of the recess. Then apply self-adhered flashing to cover the back and side corners of the shelf, installed up the walls a minimum of 4". It must be installed high enough under the rough opening to lap under the sill pan.
4. Sill Pan: Install a pre-formed sill pan (or approved alternate detail) in the window rough opening.
5. Base Flashing at Jambs: Cut a strip of 9-inch dry flashing to extend 6" above and below the rough opening at the sides. Staple it in place, putting the staples within an inch of the rough opening.
6. Base Flashing at Header: Cut a strip of 9-inch dry flashing to pass across the head of the window so that it passes an inch beyond the outside edge of the jamb flashings. Staple it in place.
7. Window Sealant: Apply a bead of sealant over the base flashing at the head and jambs. Keep the sealant within an inch of the rough opening. DO NOT APPLY SEALANT AT THE SILL.
8. Window Installation: Set the window in place, level, plumb and square. Using pan head non-corrosive fasteners, fasten the window in place by putting the screws through the pre-punched oblong holes to prevent any damage to the window flange.
9. Window Flashing at Jambs: Seal the window flange to the base flashing at the jambs with 4-inch flashing tape. The flashing must extend below the window to the sill and 2" above the window frame at the head.
10. Window Flashing at Header: Seal the window flange to the base flashing at the header with 4-inch flashing tape. The flashing must extend a minimum of 2" past the jamb flashing.
11. Building Paper First Course: Install the first layer of building paper in shingle fashion. Cut the building paper to be even with the top of the recess/potshelf and tuck it under the self-stick flashing at the edge (see step 2). Remove the release paper from the self-stick flashing and seal it over the building paper with a roller.
12. Building Paper at Sides: Install successive courses of building paper to run right to the edge of the window frame.
13. Building Paper at Top: Cut the paper short of the recessed ceiling and use flashing tape to seal the edge of the paper to the upper corner of the recess. The flashing should be centered on the corner, extending out past the face of the recess and cut to lay flat. Add a piece of flexible flashing to seal the outside corner of the recess.
14. Building Paper on Recessed Ceiling: Cut the paper which will cover the ceiling of the recess to the width of the opening and fasten it tight into the top corner so that it reaches the top of the window frame.

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