Marking Out Floor Joists

The string line would be fixed in position x in the diagram below.

Marking out floor joists.

Use a tape measure to measure 16 inches 41 cm in from the edge of the rim joist and draw a small notch. Laying a floor joist in a wood frame house is a simple procedure that can be done in 4 easy steps. Joists placed 24 on center are usually adequate. Wood joists are structural framing members that are laid upright on edge and nailed equally spaced usually 16 inches on center onto the wall plates.

And mark another joist location 4. Joists are cut to lay flush with the outer surface of the. Starting from a nail nailed at the center of one of the two outer joists already in stalled measure along the ledger making a clear mark every 24 or 16. Mark the position of each floor joist along the sill plate.

Floor joists should be spaced no more than 16 inches 41 cm apart from center to center to provide adequate stability. The layout for the following joists is then oc. See the image below for an example of joists spaced 16 on center 16 o c. Then a string line can be fixed to the top of these two new joists giving you the level for the joists in between.

Measure between the joist locations along the angle to find the on center joist spacing 5. We lay out floor joists by marking lines corresponding to one face of the joist. Joists range in size from 2 x 6 to 2 x 12 based on the distance being spanned. These marks indicate the center of each joist.

Start by aligning your top and bottom plate ends flush together and measure 15 1 4 inches to side of first stud placement. Nobody with any sense actually lays out joists by measuring to their center. Slide the tape and square along the joist until the tape reads 32 in. In this application floor joists are placed 16 oc and layout has been started from the right side.

Each corresponding measurement should be 3 4 of an inch shy of stud marks. The floor joist spacing is the distance between the centers of any two installed joists. After you have determined their spacing the layout is rather simple. Since the example house we are designing for is 12 feet wide we need to find in the floor joist span table a joist size and centering that can span 12 or wider.

Mark the joist location with a speed square 3. To level the entire floor it is best to start with the two end joists. The first joist is marked at 15 1 4 to ensure that the 4 or 8 edge of a panel will fall on the center of a joist.