Flash and Seal an Installed Window

A. Finished-Project Specification

Scope: one completed window flashing and air-seal assembly, covering the jamb flashing, head flashing, WRB head-flap integration, and interior perimeter air seal for the Project 05 window installation.

B. Required Documentation Schedule

Document	Source	Confirmation Required
Window installation record	Project 05 record	Confirmed level, plumb, square, fastened, and operational
Flashing tape and head-flashing instructions	Window and WRB manufacturers	Tape width, overlap distance, primer requirement, and head-flashing detail confirmed
Interior air-seal instructions	Foam or sealant manufacturer	Product, application method, and cure or expansion limits confirmed
Rough-opening flashing record	Project 04 record	Confirmed undamaged and passed inspection
Change documentation	Design professional / general contractor	All approved field changes incorporated

C. Preparation Materials and Consumables

• Flashing tape: manufacturer-approved self-adhered tape at the specified width, sufficient for jamb and head coverage with required overlap.
• Primer: manufacturer-approved primer for tape adhesion where required by substrate or temperature condition.
• Head-flashing component: rigid or flexible head flashing matching the approved detail, cut to the length required to extend beyond both jambs by the approved distance.
• Backer rod: closed-cell backer rod sized to the interior perimeter gap per manufacturer instructions.
• Air-seal product: low-expansion window-and-door foam or approved sealant compatible with the frame material.
• Documentation: one window flashing and air-seal record per opening.

D. Acceptance Standards

Check	Standard
Window condition	Level, plumb, square, securely fastened, and operational before and after flashing
Jamb flashing	Installed bottom to top, full adhesive contact, required overlap onto sill flashing, no wrinkles or fishmouths
Head flashing	Extends beyond both jambs by the approved distance; WRB head flap integrated over it in shingle-lap order
Sill drainage	Sill-pan outlet remains open and unobstructed by tape, primer, or sealant
Interior air seal	Backer rod and foam or sealant fill the perimeter gap without bowing the frame; shims remain in approved locations
Operation	Sash or panel operates freely after flashing and after air-seal cure

E. Review and Pre-Flashing Verification (Steps 1–4)

1. Review the window and flashing manufacturers' approved flange-flashing sequence, tape widths, primer requirements, head-flashing detail, interior air-seal method, and prohibited sealant locations. Confirm the current revision of each instruction against the project's document-control log.
2. Confirm that the window remains level, plumb, square, operational, and securely fastened before covering the flange. Recheck sill level, jamb plumb, head level, frame square, and sash operation against the Project 05 installation record.
3. Inspect the sill pan and lower flange for damage, contamination, and open drainage paths. Clear debris and confirm the sill-pan outlet remains unobstructed.
4. Do not tape or seal across the exterior sill drainage opening unless the approved system specifically requires it. Mark the outlet location clearly before beginning tape installation nearby.

F. Jamb and Head Flashing (Steps 5–14)

1. Clean and prime the flange, sheathing, and WRB surfaces as required. Observe the manufacturer's specified open time before applying tape over primed surfaces.
2. Cut jamb flashing long enough to extend beyond the flange and overlap the sill flashing by the required amount. Confirm the cut length against the approved detail before removing the release liner.
3. Install the first jamb flashing from bottom to top without wrinkles or fishmouths. Work in short sections, pressing the tape into full contact as you go.
4. Install the opposite jamb flashing using the same reference and overlap. Confirm both jambs match in overlap distance and coverage.
5. Roll pressure-sensitive flashing to achieve full contact at flange edges and transitions. Use a seam roller or J-roller and work outward from the center of each strip.
6. Install head flashing or a rigid head-flashing component in the required position above the window. Confirm the component sits above the flange and window head in the position specified by the approved detail.
7. Extend the head flashing beyond both jambs by the approved distance. Measure and confirm the extension on each side before fastening or adhering the component.
8. Integrate the WRB head flap over the head flashing so water from above sheds outward. Lower the head flap down over the head flashing in shingle-lap order; do not tuck it behind the flashing.
9. Tape diagonal flap cuts and upper flap edges only as required without creating reverse laps. Confirm each taped edge overlaps the layer below it.
10. Inspect corner transitions and patch any exposed sheathing or discontinuity. Use the approved patch method for any gap found at the head-to-jamb corner.

G. Interior Air Seal (Steps 15–18)

1. From the interior, remove debris from the perimeter gap and verify that shims remain in the approved locations. Confirm no shim has shifted or fallen since Project 05.
2. Install backer rod, low-expansion window-and-door foam, sealant, or another approved air-seal system without bowing the frame. Apply foam in controlled passes, allowing expansion room rather than overfilling the gap.
3. Maintain the required separation between interior air sealing and exterior drainage. Confirm the air seal does not extend through the gap to the exterior drainage plane.
4. Recheck window operation after foam or sealant installation and during curing where required. Operate the sash or panel at the interval specified by the product instructions to confirm the frame has not bowed.

H. Inspection and Documentation (Steps 19–21)

1. Inspect exterior laps, flange coverage, head flashing, sill drainage, interior air seal, and frame condition. Compare every element against the Acceptance Standards table.
2. Correct failed adhesion, blocked weeps, bowed frames, voids, or reverse laps using the approved repair method. Remove and replace failed sections rather than layering new material over a defective one.
3. Photograph and document the completed window water-control and air-seal assembly. Label each photograph with the opening ID for later reference at the Project 19 full exterior inspection.