How much does it cost to spray foam a 20x20 garage?

Cost to spray foam a 20x20 garage, which is 400 square feet of floor but walls and ceiling area larger, depends on whether spraying walls only, ceiling, open or closed cell, thickness, and labor, similar to estimating storage organization cost. For 20x20 garage with 8 foot walls, wall area is about 640 square feet plus ceiling 400, total about 1,040 square feet, minus doors and windows. For open-cell spray foam at 3.5 inches in walls and 5.5 inches in ceiling, cost is typically $1.50 to $2.50 per square foot, so total $1,500 to $2,600 for walls only, and $2,500 to $4,000 for walls plus ceiling. For closed-cell at 2 inches, cost is $2.00 to $3.50 per square foot, so walls only $1,280 to $2,240, walls plus ceiling $2,080 to $3,640. DIY kits cheaper, Froth-Pak 650 board foot kit $400 to $600, need 2 to 3 kits for walls, so $800 to $1,800 material only. Professional installation includes labor, equipment, and cleanup, higher but better quality. So spray foam 20x20 garage costs $1,500 to $4,000 professionally for open or closed cell depending on thickness and whether ceiling included, with closed-cell more expensive but higher R-value and moisture barrier, open-cell cheaper but needs thicker.