DIY Shed Cost Calculator

This calculator determines your total project expense by individually computing the material requirements and costs for three main structural components: the foundation slab, the framing walls, and the roof system. First, the floor area is established by multiplying the shed length by the shed width. Wall area incorporates perimeter dimensions, wall height, and gable extensions. Roof area is derived using the rafter length, which accounts for roof rise and custom overhang dimensions using the Pythagorean theorem. Finally, each component's surface area is multiplied by its respective local unit price (PriceSlab, PriceWall, and PriceRoof) and summed together to provide your total cost.

Imagine you want to build a classic gable shed that is 10 feet long by 8 feet wide with an 8-foot wall height and a 2-foot roof rise. You include a 1-foot roof overhang. Assume your material pricing is $6 per square foot for the concrete slab, $15 per square foot for wall construction, and $10 per square foot for roofing materials. First, the floor area is 10 × 8 = 80 square feet, leading to a slab cost of 80 × $6 = $480. Next, the wall area calculates to approximately 320 square feet, giving a wall cost of 320 × $15 = $4,800. The roof rafter length factors in the pitch and overhang, resulting in a roof area of roughly 130 square feet, totaling $1,300 for the roof. Adding these figures together ($480 + $4,800 + $1,300), your estimated total DIY shed cost is $6,580.

Always add a 10% to 15% contingency buffer to your final calculated material cost to account for lumber cuts, fastener waste, and minor hardware price fluctuations. Check your local municipal zoning laws and homeowner association (HOA) guidelines regarding setback requirements and maximum allowable square footage before pouring your slab. Finally, design your shed dimensions around standard lumber lengths (such as 8, 10, or 12 feet) to minimize waste and reduce cutting time.