A Guide to Building Slanted Roof Framing for Sheds

Constructing a slanted or sloped roof on a storage shed can seem intimidating for DIYers. But with proper planning and step-by-step instructions, you can frame and build an angled roof that elegantly complements your backyard shed.

We'll cover how to determine the right slope, securely cut and position rafters, attach sturdy roof decking, and finish the exterior with shingles or metal roofing. With focus and some fundamental carpentry skills, you can protect your shed contents from the elements while enhancing your outdoor living area.

Determine the Slope and Dimensions for the Slanted Shed Roof

The degree of slant or pitch you choose for your shed roof impacts weather resistance and aesthetic appeal. We'll show you how to settle on angles and calculate dimensions to construct a sloped roof properly suited to your plans.

Calculate Desired Slope/Pitch

The terms slope and pitch refer to the angled "rise" and "run" of your roof. Generally, steeper slopes promote water runoff but require more complex framing. For sheds, pitching the roof between 3/12 and 5/12 allows drainage while keeping construction straightforward. This means for every 12 units of horizontal roof length, the slope rises 3 to 5 vertical units.

Measure Overall Shed Dimensions

Determine your shed's length, width, and projected height to figure required rafter lengths. Account for features like overhangs, trimmed fascia, and gabled end walls in measurements. Having precise numbers for the perimeter will make cutting rafters and roof decking easier.

Mark Rafter Locations on Shed Walls

Based on your slope and shed size, calculate how many equally spaced rafters you'll need. Mark their attachment points with a chalk line snapped parallel to walls for alignment. Spacing rafters 16" to 24" apart is common.

Cut the Rafters for the Sloped Roof

With measurements set, use a speed square, protractor, and table saw or circular saw to cut symmetrical rafters to length. We'll explain techniques so your angled rafter framework supports roof sheathing.

Calculate Rafter Dimensions

The length and angle of your shed's rafters depend on the rise, run, and width of your planned roof. Use these specifications and construction calculators to determine precise rafter dimensions for your project.

Cut Rafter Lumber to Size

Pressure-treated dimensional lumbers like 2 x 4s, 2 x 6s, or 2 x 8s are common rafter materials. Carefully cut your rafters to specified lengths and angles using a circular saw or a hand saw plus bench vise to safely achieve symmetrical, accurate results.

Cut Notches if Needed for Joining with Wall Plates

Bird's mouth notches allow rafters to interlock with horizontal wall plates or top plates. Cut these U-shaped gaps with a circular saw then use a chisel to fine-tune the fit. Test alignments between cuts to enable sturdy shed framework.

Install the Rafter Framework

With angled rafters cut, position and securely connect them into the sloped roof's structural skeleton prior to adding decking and shingles.

Anchor Top Wall Plates Securely

Verify shed wall plates are straight, level, and robustly fastened into place. Improperly aligned walls and framing jeopardize the roof's integrity under weight loads and weather stresses over time.

Set Rafters into Place

Use helpers or temporary supports to hold the angled rafters while fastening into wall plates. Ensure bird's mouth notches align properly for strongest connections. Cautiously pivot rafters into roof slope position.

Make Sure Rafters Are Aligned and Correctly Spaced

Before permanently affixing, confirm precise vertical and horizontal rafter placement against chalk lines on walls. Use measurements and templates to evenly space. This prevents skewed rows or gaps.

Secure Rafter Connections with Brackets/Ties

Toenail or screw rafters into wall plates using galvanized fasteners. For extra stability, install metal hurricane ties or brackets secured with nails. This makes the peaked framework robust.

Install Roof Decking on Angled Rafters

Once rafters are reliably framed, the next phase is attaching deck material across them as a sturdy base for shingles. We'll review suitable roof sheathing products and application methods to cover the slanted area.

Choose Roof Sheathing Material

Plywood sheets rated for roofing offer durability at a lower cost. Oriented strand board (OSB) panels or metal sheets are other options. Choose sheathing able to withstand weight, foot traffic, weather, and designed for sloped installation.

Start at the Bottom Edge and Work Upwards

Applying bottom or eave strips first ensures aligning upper sheets easier. This provides a straight edge to follow as you build upwards. Use overhangs or trim boards to finish outer sides.

Allow for Overhang if Desired

An overhanging eave provides shade, directs runoff away from walls, and gives a finished roofline look. Account for desired overhang width when taking initial measurements and cutting decking or trim-boards to appropriate lengths.

Secure Decking to Rafters Below

Use galvanized nails or exterior screws to strongly anchor each roof deck sheet into the underlying rafter or truss. Stagger fasteners evenly for reliable wind and weight resistance.

Waterproof and Finish the Slanted Roof

Preparing for and installing asphalt composite shingles or metal panels gives weather protection. We'll summarize how to make the sloped roof surface watertight for durable performance.

Install Water Barrier Like Felt Paper or Ice Guard

Apply adhesive-backed synthetics, felts or membranes across the roof decking overlapping seams prior to shingling. This shields from leaks, wind-driven rain while permitting ventilation.

Secure with Battens/Caps if Needed

Some barrier products require vertical wood or metal strips fastened over laps to hold materials evenly in place until shingling. This prevents blowing, tearing or gaps during construction.

Add Final Exterior Roofing Material

Starting from the bottom edge, staple on overlapping rows of asphalt shingles or fasten interlocking metal panels. Work upwards diagonally or in a zigzag pattern across the sloped area. Avoid misalignments.

Install Ridge Caps/Flashing

Seal the crown of the roof with cut shingles or angled flashing pieces. Integrate these with or over terminal ends of roofing products. Use waterproof sealants if needed to avoid leaks.

Build Roof Supports and Trimmings

Enclose gable overhangs, smooth fascia appearance, and proper drainage systems with these finishing steps for a polished shed and slanted roof.

Frame Gable Ends

Box-in gables under the sloping sides with horizontal, vertical and angled trim boards. Anchor securely into surrounding rafters and decking to prevent sagging or separation over time.

Install Fascia Boards

Painted wood or vinyl fascia covers rafter overhangs for a tidier, more refined edge. Use galvanized nails to prevent rust stains. Oversize gutters attach to fascias to direct water away from the structure.