How do I Add Sideways to a Garage?

Foundation and Floor

• 1

  Measure out foundations for your garage addition and stake it off. Using a backhoe, level the area that will be the interior and dig a ditch below the frost line for the addition's foundation. If you don't know the frost line in your area, check the local building codes.

• 2

  Build forms for concrete footings from plywood and stakes. Set a string line on both the outside and inside edge of the footing and line stakes on both string lines. Cut plywood to the appropriate height and attach it to the stakes to form a wall.

• 3

  Pour concrete into the form and place rebar vertically into the wet concrete where the rest of the foundation wall will be poured. This will reincforce and create a bond between the footing and the foundation.

• 4

  Wait for the footing to harden. Build a second form about six to eight inches thick on top of the hardened footing for the foundation wall. Pour concrete into this form and place L-shaped carriage bolts into the concrete at even intervals of three to four feet, making sure that they're level and won't interfere with stud placement. Allow the concrete to harden.

• 5

  Prepare the interior space for a concrete slab by putting down a layer of pea gravel for drainage. Lay wire mesh on the entire surface, using tie wire to bind the panels of mesh together. Pour the concrete and level it off with a screed. Edge it with a concrete edging tool and do any other finishing trowel work that needs to be done. Allow the concrete to dry.

Removing the Wall

• 6

  Shut off any electricity that may pass through wiring in the wall you'll be tearing out. Since this is a garage, you probably won't need to worry about water, but if there are pipes in the wall you'll need to find a way to reroute them or cap them off.

• 7

  Remove any drywall or plaster from the interior of the wall. A prybar, a sledgehammer, and a standard claw hammer are the best tools for this job.

• 8

  If the wall is load-bearing, install a temporary beam before continuing the wall removal. Attach the beam to the adjoining walls with bolts or hangers directly in front of the wall to be removed. Once this is done, knock out the studs using the sledgehammer, prybar and hammer. Use a reciprocating saw to remove nails and bolts.

Framing the Addition

• 9

  Build walls out of 2-by-4 or 2-by-6 lumber. Space studs 16 to 24 inches apart and attach them with screws or nails to the top and bottom plates. In the bottom plate, drill holes for the bolts in the foundation. Frame openings for windows and doors by adding headers, made out of two 2-by-10 lengths of wood nailed together, and sill plates made out of 2-by-4 or 2-by-6 between king studs that mark the sides of the window or door.

• 10

  Raise the walls and brace them by attaching 2-by-4 planks to the wall and staking or propping them against the ground as needed. Anchor the walls to the floor by tightening washers and nuts on the bolts.

• 11

  Add rafters of 2-by-4 or 2-by-6 planks to the top of the new wall and the top of the old wall. Notch the rafters where they meet the new outer wall so that they rest on top and have about a foot of overhang. Attach the rafters with screws and rafter brackets at both ends.

• 12

  Lay plywood or paneled siding on the outer walls and attach it with nails or screws. If you're not using paneled siding, side the addition after putting up the plywood. Lay plywood on the roof and attach it with nails or screws, then cover it with tar paper. Lay shingles in the roof and nail them in place.

• 13

  Install windows or doors according to manufacturer's specifications. Consult an electrician before installing any wiring in the new wall. If desired, enclose the wall with drywall using drywall screws.