Building your own garden shed saves money over purchasing prefabricated kits or hiring a builder to handle the construction. The cost to build a shed depends on the lumber and supply prices offered in your area, but approaching the lumber yards armed with a basic idea of cost allows you to know what is really the best deal.
For a basic 12×20 shed your costs will be similar to the following:
The lumber that comes in contact with the ground – primarily your foundation lumber – must be pressure-treated to withstand rot and pests. This lumber is one of the more costly items, running as high as $6 for a 2x4x8, or around $150 for the entire shed.
Less expensive lumber, such as pine 2x4x8 boards, work well for the basic framing of your shed. Prices vary by region, but on average work out to as little as $2 a board. A basic 12×20 shed uses approximately 150 of these boards, for a total of $300.
Plywood becomes the exterior sheathing, roof sheathing and the floors. You need thicker 5/8 inch plywood for floors, but thinner ½ inch plywood is suitable for the rest of the shed. Standard 4×8 plywood sheets run about $16 each, for total of about $600 for the entire shed.
The cost of your roof depends on the style of roof you decide upon. A simple asphalt shingled roof cost less than a preformed metal roof, but will require more maintenance and upkeep over the years. Corrugated, galvanized sheeting is a less expensive, low-maintenance option. You also need roofing felt, regardless of the type of roof you decide upon. On average, roofing supplies for a 12×20 shed are around $250.
Windows and Doors:
You’ll need at least one window, and preferably two on a 12×20 shed to ensure you have enough light, especially if you want to use the shed as an office or work shed. A large door to move lawnmowers and other equipment in and out is also a necessity. Plan to spend around $400 minimum for theses materials.
On top of these costs, you also have the cost of your foundation, as well as the various fasteners and other hardware needed to complete your shed. Budget at least $2,000 for the cost to build a shed of this size, but keep in mind that the number can easily go up depending on the quality of materials you choose.