How to Build a Garage Yourself

And an Alternative Combo Strategy of DIYing and Subcontracting the Work

Garage

Image Supply / Getty Images

Overview
  • Working Time: 2 - 4 wks
  • Skill Level: Advanced
  • Estimated Cost: $15,000 to $40,000

Building a garage on your property protects a number of your most valuable assets—your vehicles. Rain, snow, and the sun’s UV rays can quickly deteriorate non-garaged vehicles.

Not only that but building a garage adds substantial value to your property. On average, homes with garages appraise at 20 percent more than homes without garages. Plus, homes with garages sell faster and easier than those without garages.

Building a garage by yourself is a serious project but can be done with enough motivation, planning, and knowledge. By taking on the project yourself or contracting out portions of it, you could save money over hiring a full-service general contractor.

Placement

Garages can be attached to the side of the house, the back, or sometimes to the front. Attached garages allow you to access the garage from the house. These garages cost more to build than detached garages, but they have greater resale value.

Consider zoning and setbacks. Garages on the side of the house must be set back from the property line a certain distance that's determined by local zoning restrictions. Garages at the rear have fewer issues with zoning and setbacks, but you'll need to provide access alongside the house for the vehicles.

Before Getting Started

A garage is a substantial structure and its plans should be drawn up by an architect, a contractor, or a design-build company. Often, the exterior design of the garage is predetermined by the style of the house. Siding, roofing, color, and windows usually match those of the house itself.

A two-car garage generally will be 24 feet by 24 feet, with one or two garage doors, one door to the house, a side door to the exterior, and a window or two.

You will also need to obtain the full range of building permits—even if you build the garage by yourself. The structure itself must be permitted and inspected by local municipal inspectors. 

Components within the garage will need separate permits and inspections. An attached garage will need electric wiring to supply the outlets and lighting required by code. If you install a laundry sink, laundry facilities, or an outside hose bib, you will need to obtain plumbing permits, too.

Building a garage is an advanced project that requires you to be adept at many trades. One alternative that still saves on cost is to contract out some parts of the process and to do others yourself.

What You'll Need

Equipment / Tools

  • Nailer and compressor
  • Cordless drill
  • Electric saws
  • Tape measure

Materials

  • Two-by-fours
  • LVL beam
  • Siding
  • Shingles
  • Plywood or OSB sheathing
  • House wrap
  • Garage door
  • Drywall
  • Concrete

Instructions

  1. Build the Foundation Footers

    The garage should have foundation footers that extend below your area’s frost line, if required. A backhoe will dig into the soil to this depth. Wooden concrete forms will be built for the foundation. Concrete is poured into the forms and left to cure.

  2. Pour the Concrete Slab

    A concrete contractor will tie metal rebar to act as a strengthening base for the concrete slab. Then a concrete truck will pour the slab in one continuous pour, while concrete workers screed out and finish the concrete.

  3. Build the Walls

    Carpenters will build the walls with double sill plates at the top and bottom with vertical studs placed every 16 inches. Spaces are left for the windows and doors. Headers for the 9-foot garage doors may be made from two-by-tens or laminated LVL beams.

  4. Build the Roof

    Pre-built roof trusses arrive by truck and are moved into place by crane, with workers nailing the trusses down.

  5. Install the Shingles

    Moving from bottom to top, overlapping rows of roofing membrane are rolled out horizontally. Shingles follow. Like the membrane, shingles begin at the edge of the roof and move upward in overlapping rows.

  6. Install the Sheathing and House Wrap

    Exterior grade 3/4-inch plywood or OSB board is nailed to the garage exterior and covered in house wrap.

  7. Install the Siding

    Siding is installed over the house sheathing. The siding is brought directly up to the house siding so that the two stylistically match.

  8. Install the Doors

    A door is installed between the garage and the house. Most codes require a solid, fire-resistant door. For the exterior door, install an exterior pre-hung door.

  9. Install the Garage Doors

    The garage door tracks are installed on the garage ceiling. The doors are installed in the door openings, then attached to the tracks.

  10. Install Electrical Wiring

    Connect with the house’s electrical system. If you have available circuit locations on the service panel, run the lighting, outlet, dryer, and garage door circuits from them.

  11. Install Plumbing Lines

    If the garage will have laundry facilities, plumbing lines are tied into the house’s hot and cold water supplies and drainage system. For a hose bib, a cold water supply line ties into the house’s supply and extends through the walls to the outdoor faucet location.

  12. Hang and Finish the Drywall

    Drywall is installed on the inside of the garage. Code may require special fire-resistant drywall on the side of the garage that abuts the house.

DIY vs. Hiring a Professional

Building a garage is like building a smaller, pared-down house. Major features such as roofing, foundation, and wall systems are the same. Building your own garage by hand requires you to be adept at many trades and have a generous time frame to work with. So, most homeowners choose to contract out their garage building project. 

Hiring subcontractors for some jobs and doing other jobs by yourself is an alternative. Not only does this reduce the cost of some of the subcontractor projects, but it also eliminates the 10- to 20-percent contractor markup fee. If you are an advanced do-it-yourselfer, you may want to divide the tasks like this:

Projects to Do Yourself

  • Run electricity to the garage from the house
  • Establish circuits for lighting, outlets, and the garage door
  • Hang and finish the drywall
  • Install the garage doors
  • Install the windows
  • Install the doors to the house and to the exterior

Projects for Professionals

  • Build the foundation
  • Pour the concrete slab
  • Build the walls
  • Install the siding
  • Build the roof structure
  • Install the shingles