How to Anchor a Deck to a House

Mark the height of the ledger's top edge at both ends of the wall with a tape measure and pencil; the ledger's height equals the finished deck height minus the deck planks' thickness. Stretch builder's twine between the marks. Attach a line level to the twine and check the relative levelness of the marks. Adjust the marks as necessary to achieve levelness.

Run a chalk string line between the marks. Pull the line taut. Snap the line to lay out a straight line that represents the ledger's top edge. Mark, level and lay out a line for the bottom edge of the ledger. Mark the ledger's overall width along the top and bottom layout lines. Set a straightedge across corresponding marks and run a pencil along the straightedge to lay out lines that represent the ledger's ends.

Score along the ledger's layout lines with a utility knife if you are working on wood siding. Score along the lines with a circular saw and masonry blade if you are working on stucco. Pry and saw wood siding from the wall with a pry bar and hammer. Demolish the scored portion of stucco with a hammer.

Slip the top edge of the flashing underneath the siding at the top of the demolished area and overlap the flashing's lower edge over the siding at the bottom. Fasten the flashing to the wall's studs with roofing nails or exterior fasteners. Attach a wood bit to the power drill. Drill starter holes through the ledger's face, roughly two per stud and evenly spaced along the ledger's height.

Set the ledger into the removed portion of the siding. Place a level on the ledger's top edge. Align the ledger's horizontal position with the level. Drill through the ledger's holes and into the wall's studs with the same bit to extend the starter holes into the stud's edges. Attach a nut driver to the power drill.

Set the ledger into its recess and align the ledger's holes with the holes in the studs. While holding the ledger level, use the power drill to drive lag screws through the starter holes and into the wall's studs. Load a tube of caulk into the caulking gun. Apply a smooth bead of caulk to the joint between the flashing and the ledger's ends and edges.