How To Set A Wall Under Floor Joists

Stairway and balcony openings are framed using bearing walls or beams below.

How to set a wall under floor joists.

Run a stud finder along the ceiling to locate the joists. Space nails at least 24 inches on center or according to local requirements. Align the wall s top plate directly beneath the parallel joist s bottom edge. Cantilevers allow the floor to be framed out past the foundation.

Floor frames must be designed to carry the load. Tilt the wall onto its bottom plate and hoist it upright. Sheeting the floor with osb or plywood. Plumb the wall and anchor the wall to the joist and subfloor with the nail gun.

The rim joist sits vertically on top of the sill plate along the outside of the frame to create a lip for the main floor joists. The load capacity of the floor under the tub is based primarily on the size spacing and span of the floor joists. The outside of the rim joist is flush with the stud wall beneath to ensure that the house boxing and siding will be even. Limit the length of notches to one third of the joist depth.

Beams under the floor joists allow the floor joists to go over. No notching in the middle third of a joist. Cut and install the floor joists between the rim joists. Maximum notch depth in the outer third of a joist is one sixth of the joist depth.

You ll use the same size lumber to assemble the rim joists as you will for the main floor joists. If the joists are parallel to the new wall adjust the layout so that the wall is directly under a joist. Some newer homes have manufactured i beam shaped joists. The rim joist boards typically 2 by 10s or 2 by 12s install edgewise around the perimeter of the first floor top wall plate also called the tie plate.

Use a chalk line to mark where you want to place the new wall along the floor. The maximum depth of a notch at the end of a joist where it rests on a wall or beam can t exceed one quarter of the joist depth. Begin wall assembly by planning the layout of the new wall. Ceiling joists are usually 2 by 6s or sometimes 2 by 4s if it is an older home.

Beams in the floor require joist hangers.