What to Plan Before Building a Detached Garage

A detached garage looks like a simple building: a slab, four walls, a roof and a door. The garages that work best for years are the ones planned around real measurements and real use. Here is what to think through before you settle on a size and location.

Measure what you'll park

Standard garage dimensions are designed for average cars. Many families in our area drive full-size pickups, and many crew cab trucks are close to 20 feet long. Start by measuring:

• Overall length of your longest vehicle, bumper to bumper, plus any hitch
• Width with mirrors folded and with doors fully open
• Height including roof racks, ladder racks or a lift kit

Then measure any trailer, boat or side-by-side you want to store, including the tongue.

Sizing worksheet

Use these steps to estimate depth and width:

• Depth: longest vehicle length, plus about 3 feet to walk in front, plus the depth of any bench or cabinets at the back wall.
• Width: each vehicle's width with doors open, plus clearance between vehicles and to the side walls, plus any bench or storage along a side wall.
• Door height: tallest vehicle height plus a margin. An 8-foot door suits many lifted trucks and racks; taller doors suit trailers or RVs.
• Ceiling height: add more if you want overhead storage racks or a vehicle lift.

For example: a 20-foot truck, plus 3 feet to walk around, plus a 2-foot deep bench at the back, comes to 25 feet. A 24-foot deep garage would be tight; 26 to 28 feet would be comfortable.

Plan the workshop

If you want to work in the garage, decide where. A bench along a side wall under a window gets daylight and is usable even when vehicles are parked. A bench behind the vehicles is often blocked. Plan:

• Outlets along the bench wall at bench height
• Dedicated circuits for tools like compressors or table saws
• Good overhead lighting
• A service door near the bench to carry materials in

The driveway approach

A garage is only as useful as the path into it. Consider:

• The turning path from the street or existing driveway
• Room to back a trailer in straight
• The slope between the drive and the slab
• Whether a new curb cut or ditch crossing is needed

On long rural driveways in Liberty Hill, the approach can be a significant part of the project.

Power

Even if you only plan to park in the garage today, think about what you might want later:

• EV charging
• A compressor, welder or other high-load tools
• A mini-split for heating and cooling
• Exterior lighting and a security camera

Sizing the electrical feed from the house for future use now is much easier than trenching again later.

Drainage

A new slab and driveway change how water moves across the yard. We set the slab slightly above grade, shape the ground to slope away on every side, and plan where roof and slab runoff will go. On flat lots, like many in Jarrell, this is often the single most important part of the plan. Gutters, a swale or a culvert at the road ditch may be part of the solution.

Location on the lot

Beyond setbacks and easements, think about:

• Distance from the house for daily convenience
• Noise from a workshop
• Whether the garage blocks views or light to the house
• Access for concrete trucks during construction
• Septic systems, wells and trees to avoid

Reviewing door and equipment clearances

An overhead door opening is not the same as clear space inside the garage. Track position, open-door height, lighting and structural members can affect how tall equipment fits. If a vehicle lift or roof-mounted equipment is part of the plan, provide its actual dimensions and installation requirements before the structure is designed.

Walk through the intended layout with vehicles represented at their full size, including open doors and the area needed to unload. Then add the bench, shelves and freezer. The useful footprint is the space left for movement once those items are in place, not simply the slab dimensions printed on a drawing.

Comparison: two-car or three-car

• Two-car: fits two vehicles comfortably, often with limited workshop space. Smaller footprint, less slab and driveway.
• Three-car: fits two vehicles plus a dedicated workshop bay or a third vehicle. More flexible, and the most common request from families with a work truck and a shop hobby.

Before you meet with a builder

• Vehicle and trailer measurements
• A list of how you'll use the garage now and later
• Your survey and any HOA guidelines
• Photos of where water stands after a heavy rain

Learn more about our approach to detached garages, and when you're ready, we'll walk the lot with your measurements in hand.