Framing your walls is an important part of any basement renovation. Frame your walls with construction grade lumber. Use 2x4 boards to provide substantial walls as well as lots of room for insulation and running wires. Use pressure treated wood for the bottom plate (it will actually rest on the concrete floor), as it will resist moisture better than white wood. These steps will help you frame your walls and have the basement of your dreams.
Step 1 - Measure
The easiest way to frame walls is to build the sections on the floor then raise each wall section into place. To determine the height of the framed walls, measure from the floor to the bottom of the floor joists in a number of places. Use the shortest measurement.
The top and bottom plates should be 1.5 inches thick, so you need to deduct that from the length of your studs. It's also a good idea to build your walls at a height that will float, meaning you need to leave some space between the top of the framed wall and the bottom of the floor joist or ceiling. Leave an extra .75 inches. This extra space will allow the wall to actually "float" up or down if the basement floor moves, which is common in older homes.
Step 2 - Calculate Stud Length
Calculating stud length is relatively easy. For example, if the ceiling height is 93 inches and the top and bottom plates are 1.5 inches each, or 3 inches total, you would also include .75 inches for the floating wall, so you would want your individual studs to be 89.25 inches (93 inches minus 3.75 inches).
Lay your top and bottom plates side by side on the floor and mark them. When laying your studs on 16-inch centers, the first and second studs aren't 16 inches on center. Rather, the distance from the end of the plate to the center of the second stud is 16 inches, and each subsequent stud is 16 inches on center. At the opposite end of the wall, it is 16 inches from that corner to the center of the second stud from the end.
Nail the studs in place using 3.5-inch coated nails. Raise the wall section into its position with the back of the bottom plate against the chalk line. Hold the wall section temporarily in place by driving a nail into the bottom of a floor joist. Make sure the bottom plate is properly positioned, then use a power nailer to fasten the bottom plate to the concrete floor.
Step 3 - Level the Structure
Use a level to ensure that the framed wall is plumb, then fasten the wall permanently to the floor joists. Special L shaped framing clips are available that will attach the walls to the floor joists while still allowing them to float, or you can drill a hole through the top plate and put a spike through the hole into the joist. Don't drive the spike all the way through.
By following these easy steps you will have your basement walls framed in no time. When in doubt, call in a licensed contractor to help with the job.