How to Build a Soffit Around a Drainage Pipe Along the Wall

Measure from the bottom of your basement ceiling joists to the bottom of the drainage pipe at its lowest level of slope. This provides a depth for L-shaped forms to create a structure to shape the soffit. The forms can be 8 inches wide, or larger or smaller to accommodate the drainage pipe diameter plus its distance from the wall and 1 ½ inches for your support studs.

Run a 2-by-4 to act as a mounting bracket along the wall, so that the top of the bracket lines up with the lowest point of the drainage pipe and the bracket is horizontal as gauged by a spirit level. Screw it into the wall studs. Run as many 2-by-4s cut from 8-foot lengths as needed to cover the entire run of the drainage pipe.

Run a 2-by-3 support stud along the bottom of the floor joists placed so its inner edge nearest the wall lines up with the widest point of the side of the drainage pipe that is farthest from the wall. Run as many 2-by-3s as needed to cover the entire run of the drainage pipe. Cut a second set of 2-by-3s of equal length to reinforce the inner corners of your L-shaped forms.

Create an L-shaped form out of 2-by-3 stock. The bottom of the L runs horizontally from the bottom of the mounting bracket, and the upright side of the L runs vertically down to meet it from outer edge of the support stud. Measure these distances for your drainage pipe -- for a 6-inch drainage pipe, the vertical leg may be about 8 inches and the horizontal leg about 10 inches, depending on your scenario. Connect the two legs with two wood screws.

Install your first L-shaped form at one end of the drainage pipe. Construct and install additional L-shaped forms, one for every 16 inches of soffit. Slide the second set of 2-by-3 support studs, with the long edge vertical, into the inside corner of the L-shaped forms and fasten with a wood screws to the upper arm of the form.

Fasten drywall to the soffit forms with drywall screws, so that the seams of the boards meet over every fourth soffit form. Apply joint compound and tape to the seams and corner bead and joint compound to the corner. Allow to dry and paint to match your walls.