How to Attatch Stair Stringers to the Floor
- 1). Measure the space between each stair stringer using a tape measure. Cut 2-inch-by-4-inch or 2-inch-by-6-inch pieces of lumber, which will be used as the bottom plates, to length with an electric saw.
- 2). Cut half an inch from the tip of a tube of construction adhesive, such as Liquid Nail. Puncture the seal and slip the tube into a chalk gun. Apply a generous amount of adhesive to the bottom faces of the plates.
- 3). Slip the cut bottom plates, adhesive side down, between the stair stringers. Slide the bottom plates forward until the outside edges are flush with the stringers' front rises. Step down on the blocks to distribute the adhesive evenly between the bottom plates and the floor.
- 4). Fasten bottom plates to wooden subfloors by hammering 16d nails through the plates directly into the floor. Space the nails 8 inches to 12 inches apart and stagger them across the faces of the bottom plates.
- 5). Fasten bottom plates to masonry subflooring by drilling two half-inch holes at each end of the plates directly into the masonry floor using a hammer drill. Slip 1/2-inch wedge anchors into the drilled holes and tighten them with a ratchet.
- 6). Face or toe nail the stringers directly to the installed bottom plates using 16d nails.