Framing a Room Under a Deck

Measure the space between the deck posts. Wear safety goggles when sawing the wood. Cut two boards that are 2-by-4 to fit in each section. These boards are the top and bottom plates of each wall section.

Lay the top and bottom plates for the first section flat onto the ground between the posts. Measure the distance between the 2-by-4s and the beam above them that supports the deck. Cut wall studs from 2-by-4 boards to fit that length. Use enough studs so they're spaced no more than 16 inches apart.

Nail a stud into each end of the bottom plate by driving two nails through the bottom edge of the bottom plate and into the bottom of each end stud.

Nail studs into the bottom plate in between the end studs, keeping the studs no more than 16 inches apart.

Place the top plate against the top of the studs. Nail it to the studs the same way you nailed the bottom plate to the studs.

Lift the frame into place between the posts in the first section. Nail the top plate to the beam underneath the deck, and the end studs to the sides of the posts. Stagger the nails in an alternating pattern every 6 inches.

Screw the bottom plate into the slab using masonry screws and a hammer drill. Use one screw every 6 inches.

Assemble and raise the other sections of framing, using the same process that you used for the first section.