Excerpted from JLC Field Guide to Residential Construction, published by JLC Books (JLConline.com), a division of Hanley Wood, LLC.
Gas and Water Lines/Conduit To seal around wall penetrations, use a two-piece metal plate bedded in urethane sealant. Sheathing wrap above the metal plate should lap over the plate while sheathing wrap below it should be slipped beneath.
Cantilevered Joists/Beams Cantilevered deck or balcony joists that project through the wall framing are trouble spots. Protect them with a two-part flashing sealed with urethane. The top flashing piece must overlap the bottom one.
Deck Ledger Ledger flashing needs to be more than a Z-flashing running along the top edge of the ledger board. Use metal coil stock behind the ledger. Make sure the coil stock slips under the sheathing wrap above, and drapes over the sheathing wrap below the ledger.
Electrical Fixtures Install electrical boxes and lighting fixtures on a hemmed metal flashing plate, as shown above. Do not tape the plate over the sheathing wrap; slit the sheathing wrap above the fixture and slip the plate beneath.