Proper Flashing Installation Techniques

Advanced Level

Flashing windows, doors, deck ledgers, and roof-to-wall transitions. Correct sequencing prevents water intrusion.

Materials Needed

ZIP System Sheathing
CDX Plywood
LP SmartSide

Note

Wrong flashing sequence channels water INTO the wall. Always lap upper layers OVER lower layers.

Note

Kick-out flashing at roof-to-wall transitions is required by IRC R903.2.1. Missing = concealed wall rot.

Flashing Principles

Flashing works on the shingle principle — each layer overlaps the layer below. Getting this sequence right matters more than the product.

Window Sequence

Sill membrane first (wrapping over WRB face), then window, then jamb flashing (over sill), then head flashing (over jambs), then WRB integration at head.

Deck Ledger Flashing

Self-adhered membrane on band joist before ledger. Metal Z-flashing at ledger top, tucked behind WRB.