How to Build 18x20 Storage Buildings

Storage buildings have been around a long time. They are a valuable addition to any homeowner's collection of outdoor projects. In the following article, we will discuss the material needed, as well as the steps to building your own building.

Building an 18x20 storage building
Runners as base for floor framing

Step 1

First, make sure the ground is level and suitable for building. Once this has been secured, then the 6x6 runners should be laid out and spaced about 4' apart. Observe the runners underneath the floor framing in the picture.

Step 2

Lay out the parameter of the building. Cut two of the six 2x8x20 treated boards to 17' 9" long, and the two remaining boards to 20' 0" long. Nail the 20' treated boards to the ends of the 17' 9" boards on each end to form a rectangle of 18x20. This is called the mud sill and will serve as the outside parameter of the floor.

Center 2x8s doubled and hung on joist hangers

Step 3

Use the remaining 2x8x20 treated lumber and cut them down to exactly 17' 9" long and nail them together. Place them in the center of the rec tangled floor and then hang the 2x8 joist hangers, every 16" on both sides of the doubled 2x8s and on the opposite walls. This is where your remaining 2x8x10 treated lumber will be slotted into and nailed into place with 16-penny nails.

Wall framing at corner.

Step 4

Once the floor is framed, deck it with the 4x8x5/8 treated plywood. Use the plywood to square the floor as the plywood will be cut perfectly square. Once the floor is down, you may begin framing the walls on 16" centers. Cut four of the twelve 2x4x20s down to 17' 7" and four more to exactly 20' 0". For the first wall, lay out the 17' 7" boards back to back. Measure in 16" increments across the boards and make a mark. This is where studs will be placed on 16" centers. Raise the wall and nail it to the floor while temporary bracing it with an angled board. Lay out the 20' wall and double the studs on each end spacing them about 3 1/2" apart; This will allow for nailing the corners together. Repeat on the other two walls in the same way.

Top plate

Step 5

Overlap the remaining 2x4x20s on the top of the walls so as to tie them together.


Step 6

Once the walls are up, begin framing the roof. Cut the rafters at desired angles and frame roof with appropriate pitch and over hand, usually about 12". Deck the roof with OSB and 8-penny nails, making sure it remains square. Roll out the felt paper, and finally, apply the desired roofing material--shingles or tin.