How to Mount Stairs to Siding

Measure the width of the stairs using a measuring tape. Measure the width between the outside stringers, or side sections of the stairs, so you do not include the width of the stringers in your measurement. Cut a piece of 2-by-4 lumber with a circular saw to match the width of the stairs. This 2-by-4 piece will act as an anchor board.

Measure the thickness of the stairs’ top tread to determine where you should place the anchor board on the house. Measure that distance down from the door and place a mark on the house siding where the top of the 2-by-4 will rest. Continue to make marks in a horizontal line as a guide for the anchor board placement, using a level to make sure the line is straight.

Hold the cut piece of 2-by-4 lumber flush against the house siding, using the marked line as a guide for where to place the top edge of the board. Place a level on top of the board to be sure it is straight.

Attach the anchor board to the house, using wood screws long enough to be sure that they go into the house boards beneath the siding. Use a power drill to place screws every 6 inches to hold the anchor board securely in place.

Fit the stairs over the anchor board so that the board rests snugly beneath the first stair tread and between the outside stringers. Push the stairs into place so they are directly against the outside of the house. Use a power drill to screw the stringers to the anchor board and secure the stairs in place.