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How To Build A Gambrel Shed From Blueprints

Black guy nails the boards of a gambrel roof shed

Ron Lach from Pexels

A gambrel shed has a barn-style roof that has a unique aesthetic appeal. After you have found some suitable gambrel roof shed plans for crafting your outdoor storage building, it is time to plan out the construction process.

A gambrel-style roof has two slopes on either side. The upper slope is usually at a shallow 30-degree angle, and the lower slope below is at a steeper 60-degree angle. This roof allows maximum space underneath the rafters, which makes it suitable for building a shed with a loft. The gambrel roof provides a unique barn-style historic look to your shed.

This roof style is not suitable for areas with heavy winds because high wind velocities can easily blow away the roof. The slope of the roof is ideal for areas with a lot of snow or rainfall as the water will easily slide off it.

Let us take a look at the main steps involved in building a gambrel shed.

Find The Truss Measurements

Build the shed floor first and use it as a reference to measure the width of the truss by marking a chalk line along the floor.

Find the midpoint of the chalk line and draw a line perpendicular to this middle point. Draw an exact 45-degree angle between the horizontal and vertical lines to find the precise height of each corner truss section. Every truss section will have the exact same angle at each end and the same length at the bottom and top.

Draw lines connecting the top of the three lines, the horizontal line, the 45-degree line, and the 90-degree line. The lengths between the points will be crafted using 2x4s, and each truss section will be aligned at an angle of 22.5 degrees. The number of trusses needed to build the roof framework will be determined by the size of the shed.

Building The Trusses

Lay down 2x4s on the lines you snapped, copy over the measurements, and craft four timber pieces to create the first truss. Assemble the trusses on the floor in position to complete the first truss. Check that the width of the truss from one end to the other matches the width of the shed.

Craft six gusset plates from half-inch thick plywood and secure the truss sections to each other by driving five nails at each connecting end.

Use the first truss as a template and construct four more of them. Nail the gusset plates similar to the earlier truss. 

 Black guy cuts a wooden board with circular saw

Assemble The Roof 

Align the trusses on the top wall plates and secure them at sixteen inches on center. Toenail each end of the truss to the top wall plate by driving three galvanized nails at each end.

If you live in an area with strong winds, then reinforce the roof frame with hurricane tries secured with deck screws.

First, install the loft flooring, as this will make it easier to install the roofing panels. Use half-inch thick OSB boards for sheeting the roof. Align each of the top roofing panels flush with the upper end of the outer truss. Drive 8d galvanized nails at intervals of eight inches into the edges of the roofing sheet.

Continue installing the lower roofing panels and stagger them to enhance their sturdiness. Similarly, attach the remaining roofing sheets on the other side of the roof.

Finishing Your Gambrel Roof

Build fly rafters for the overhangs by toenailing 2×6 boards along the edges. You can also create the overhangs by fastening struts between adjacent trusses. Mending plates can also be used instead of gussets for securing the truss joints.

Apply tar or felt paper over the roofing panels to increase your shed’s durability and safeguard the roofing panels. Then install drip edges along the boundaries of the shed roof to direct water drainage away from the walls.

Finally, lay down asphalt shingles over the roof to complete the construction process.

A correctly constructed gambrel roof can easily last for over three decades. It also doesn’t need support columns or beams like other roof designs. So, the cost of materials is lower compared to a mansard or pole-frame building.

The extra headroom underneath the rafters can be used for storage space and will also make roof maintenance a lot easier. You can use metal supports in the framing process to further enhance the robustness and lifespan of your shed.