How to Build a Metal Garage

Measure and mark the perimeter for the metal garage with stakes and builder's twine, according to the specifications with the metal garage kit. Measure diagonally and compare distances. If both diagonals are the same, the site is square. Excavate 8 to 12 inches, depending on manufacturer's recommendations, for a foundation.

Build wooden forms for concrete, with 2-by-4 or 2-by-6 boards, depending on depth of foundation recommended, staked securely in place. Double check building square. Compact the soil with a hand or mechanical tamper. Lay down 4 to 6 inches of gravel, depending on recommended depth, and compact with a tamper.

Pour concrete to the tops of the forms. Level the concrete with a long board and smooth with a trowel and concrete finishing tools. Place anchor bolts upright in the concrete as recommended in the instructions. The bolts should come with the kit. Coat tops of bolts with oil to prevent concrete from getting in the threads. These must be precisely placed to match holes in the bottom rails of the metal walls. Make a wood pattern to line up the holes exactly if unsure of measurements.

Lay metal components out in their intended spaces for side walls, ends and roof. Some manufacturers recommend assembling walls and erecting them as a unit, fastening them upright with anchor bolts. Other manufacturers recommend bolting bottom rails in place, then adding side and top frames and completing with siding. Follow the directions with the metal garage kit. Erect all four walls and fasten together according to kit directions.

Install roofing according to the kit directions. Some kits have metal rafters which then are covered with metal panels. Other kits have pre-built roof panels which are lifted and bolted in place. Install doors according to the kit directions.