Framing Interior Walls
There are two common types of interior wall framing. You will either be framing load-bearing or non-load-bearing walls.
When framing interior load-bearing walls you will follow the same practices and guidelines as used with exterior bearing walls. Framing of load-bearing interior walls is the practice when there is either a second floor system or roof system transferring load directly on this framing. ( I want to point out the need to make sure if you are working with an interior load-bearing wall then you will need to transfer this load down to lower level bearing support.
As with exterior framing it is acceptable practice to frame interior load-bearing walls with standard stud framing either on 16 or 24 inch centers with double top plates. Properly sized headers are also required over openings in a load-bearing interior wall.
When framing interior non-load-bearing walls you will have much more latitude. While I still encourage that your framing includes studs placed either 16 or 24 inch on center you have the option of single or double top plates. I recommend staying with double top plates as this allows your framing to all line up with same length stds.
During framing of non-load-bearing interior walls you can run walls either parallel or perpendicular to roof and floor joisting. When framing your wall parallel to roof joists you will want to anchor 2×4 blocking between the joists no more than 24 inches apart so that you can anchor your interior wall framing to a solid surface.
When framing your walls parallel to floor joist you will not need any additional bracing so long as your sub floor is at least 5/8 to ¾ inch thick. In this case you will be able to nail directly through the bottom plate into the sub floor to secure the wall.
Framing Intersecting Walls
When framing intersecting 2×4 interior walls it is becoming a common practice to nail a 2×6 to the back of the last stud in the form of a tee to create the blocking for the inside corner on each side. Another popular process is ladder framing to attach the walls when the intersect falls between two studs in the other wall.
Before you finish the framing process remember that you will need to provide blocking at all wall connections to insure adequate backing at all corners and ceiling intersects to anchor and support drywall or other finish products.
Proper blocking is a very important part of any interior wall framing project. This framing blocking will include wood support for plumbing, heating, and electrical as needed. It will also include blocking for areas like shelving support, stair railing support, cabinet anchoring strips and towel bar blocking.
Here is a link to Framing Interior Walls Practices by the American Wood Council.