# How to Frame a Raised Shed Floor

Raised shed floors are elevated above ground to prevent moisture damage to wooden joists and plywood subfloors. Typically, spaced concrete piers that have redwood caps support the girders for a raised floor, and joists install atop the girders. When laying out a shed floor, the piers are spaced according to the size of the lumber such as 2-inch by 4-inch or 2-inch by 6-inch. Calculations for spacing of the piers based on the size of the lumber are available at a local building department. Framing a raised shed floor is an ideal opportunity for a do-it-yourself enthusiast to apply basic carpentry skills.

## Hardware and Girders

#### 1

Determine the longest sides of the floor to establish the direction of girders that support the floor joists. Floor joists install perpendicular to the long sides, which provides maximum support for the subfloor. Skip this step if the floor is square.

#### 2

Mark the center of the redwood caps on each pier at the end of a line of piers, using a carpenter's pencil. Snap chalk lines between the marks from end to end on each line of piers as references for framing angles that attach the girders to the piers.

#### 3

Use the chalk lines as references and position 1 7/16-inch by 2 1/2-inch framing angles atop each redwood cap with one side flat atop a cap and the opposite side pointing upward. The outside corner of each angle aligns with the corresponding chalk line. Attach each angle to a cap, using 1 1/4-inch hanger nails and a framing hammer.

#### 4

Determine the length of the girders by measuring the distance of a line of girders from end to end and adding 24 inches for overhangs. Typically, a shed floor overhangs the outermost piers 12 inches on each end and both sides. The overhangs can be shorter, if desired. Note the overall measurement of the girders.

#### 5

Refer to the calculations from a building department to determine if the girders are 2-by-4 or 2-by-6-inch framing lumber. Place several lengths of the lumber flat atop sawhorses. Measure and mark each to length based on the overall measurement of the girders. Square the marks across the wide face of each, using a builder's square. Cut each girder at the mark with a circular saw.

#### 6

Position the girders on edge atop a line of piers with one edge against the raised sides of the framing angles. Move the girders either way, as necessary, so the overhangs at the piers at each end are equal. Attach the girders at the piers with hanger nails through the raised sides of each framing angle and into the sides of the girders.

## Framing the Floor

#### 1

Start at one end of a girder at one side of the floor. Hook the end of the measuring tape onto the end of the girder. Draw out the measuring tape as you mark the upper edge of the girder every 16 inches to make a layout for the floor joists. Repeat this and make layout marks on the girder at the opposite side of the floor, starting from the same end of that girder.

#### 2

Count the number of layout marks from end to end on a girder to determine the number of floor joists. Include an additional joist at each end. Measure the distance from the outer edge of an outermost girder to the outer edge of the outermost girder at the opposite side of the floor and add 24 inches to determine the length of the floor joists. Note the length of the floor joists.

#### 3

Place lengths of 2-inch-thick framing lumber the same size as the girders flat atop the sawhorses. Refer to the number of joists and the length including the overhang. Mark each joist to length and square each mark. Cut the joists.

#### 4

Stage the joists perpendicular atop the girders and align each with corresponding layout marks on the outermost girders. Start at one end of the floor and position a joist on edge with one side aligned with the outer end of a girder. Move the joist either way, as necessary, so each end overhangs the corresponding girder the same distance. Attach the joist at each intersection of a girder by toenailing two 16-penny framing nails at 45-degree angles through each side and into the upper edge of a girder. Repeat this step and install the remaining joists at corresponding layout marks on the girders.

#### 5

Determine the length of rim joists, or fascia joists, that attach at the ends of the floor joists. Measure the distance from the outermost edge of the first joist on one end of the floor to the outermost edge of the joist at the opposite end of the floor. Cut two pieces of 2-inch framing lumber to length as rim joists.

#### 6

Position a rim joist flat against the ends of the joists at one side of the floor and align the upper edge at the upper edges of the joists. Align each end with the outer edges of the joists at each end. Attach the rim with pairs of 16-penny framing nails at each joist. Repeat this step and attach the remaining rim joists at the opposite ends of the joists. The floor is ready for plywood subfloor.

References

Warnings

- Wear eye protection when cutting lumber or plywood with a power saw.

Writer Bio

William Machin began work in construction at the age of 15, while still in high school. In 35 years, he's gained expertise in all phases of residential construction, retrofit and remodeling. His hobbies include horses, motorcycles, road racing and sport fishing. He studied architecture at Taft Junior College.