Shed Roof Framing

For most do-it-yourselfers, framing the roof is the most challenging part of building a shed. But with a little understanding of roof styles, terminology and construction, roof framing is well within the capabilities of any weekend carpenter. 

There are two basic ways to frame a shed roof. The traditional method is to cut and install all the parts—rafters, ridge board, collar ties, and ceiling joists—one board at a time. The advantage of this approach is that a single person can easily lift and nail the boards in place. However, you’ll spend a lot of time climbing up and down ladders, which can be exhausting. 

The second option is to build the roof frame on the ground to form individual roof trusses. A roof truss is a prefabricated section of the roof frame that consists of a pair of angled rafters and one horizontal bottom chord, which forms the ceiling joist. Once assembled, the trusses are lifted and fastened to the tops of the walls. Building and installing trusses is quicker and easier than piecemeal framing, but you’ll need help lifting the trusses into place.

What is a Shed Style Roof

A shed style roof, also known as a skillion or lean-to roof, is a roof that slopes down in one direction. It is flat with a steep slope. Depending on the design of the building, the slope can vary in how steep it is. While it was previously only used for sheds, it has become more popular to use on houses. The design is simple and cost-effective. It is easier and faster for a roofer to build this roof style which equals fewer labor costs. It is important to properly insulate this roof as it can get very hot or cold with the different seasons.

Lean-to Roof

A shed roof has a single sloping plane, making it the simplest of all roof frames to build. This style roof can be used on a freestanding outbuilding but is particularly well suited for sheds that are built up against another structure, such as a house, garage, stable, or barn. In those situations, a horizontal ledger board is fastened to the existing wall to support the upper ends of the rafters. Shed roofs normally have a relatively shallow slope, usually between 4-in-12 (18º) and 8-in-12 (33º). 

Tip: When deciding on the slope of a shed roof, take into account the position of the doors. A steeply pitched roof comes down lower into the doorway than a slightly less-steep roof, and that could

Gable Roof

A gable roof is by far the most common style of shed roof. It’s easily identified by its familiar A-shaped profile that has two sloping planes of equal length. Gable roofs are formed by pairs of common rafters that run at an angle from the tops of the walls up to the roof peak. A ridge board, if used, runs horizontally between the pairs of rafters where they meet at the peak.

Check your shed plans for the exact size and spacing of the lumber used to frame the roof. Most storage sheds are framed with 2×4 or 2×6 rafters, spaced 16 in. on center. The ridge board is often cut from a 1×6 or 1×8. When framing a roof with site-built trusses, you don’t need a ridge board. The rafters fit together tightly at the peak and are secured with plywood gusset plates. 

Tip: Gable shed roofs look best with a roof slope of either 11-in-12 (40º) or 12-in-12 (45º).

Saltbox Roof

A saltbox roof is similar to a gable roof except that one roof plane is slightly longer than the other. This unique design shifts the roof peak off-center so that it’s closer to the front wall, thus creating the distinctive saltbox roof. When framing a saltbox roof it’s important to follow two simple guidelines to maintain the roof’s proper proportions: First, run the rafters at 45º to create a 12-in-12 roof slope. Second, position the peak of the roof one-third of the way back from the front wall. 

Tip: When framing the roof of a shed, be sure to set each rafter directly over a wall stud, which will transfer the roof load down to the foundation.

Gambrel Roof

This design is often called a barn roof and is easily recognized by its distinctive double-sloping profile. It has two short, shallow roof planes that angle down from the peak, and then it breaks sharply to two steeper slopes that extend down to the tops of the walls. A gambrel roof is slightly more difficult to frame than other roof styles simply because it contains many more parts. The advantage though is that gambrel roofs create a very spacious interior with plenty of headroom above the ceiling joists, which can be utilized as a storage loft. Like most roof styles, a gambrel can be framed piecemeal one board at a time, or you can build trusses on the ground and then lift them into place.

Tip: When building a shed with a gambrel roof, it’s best to place the doors on the end wall because the sidewalls are typically too short to provide adequate headroom.

Hip Roof

A hip roof is a roof with a slope on all sides of the shed. They all have an equal length and come together to form the ridge. This roof has no gable or peak at the top. They can be a sturdy roof because of the four sloping sides. They do well in high wind and snowy areas because of the slant of the roof. However, hip roofs can be pricey to construct. With a more complex design, more building materials are needed.

What is the Best Roof For a Shed?

We’ve looked at some of the different styles of roofs, so which one is the best for a shed? Our recommendations are either a gable roof or a lean-to roof. Here are a few reasons why we like these two.

Gable

• A common roof type
• Has extra space above the ceiling for a loft, storage, or headroom
• Sheds rain and snow easily, especially with a higher slope
• An easy build for a beginner

Lean-To

• Inexpensive to build
• Walls protected from wet weather by the roof overhang 
• Rain and snow slides off easily, especially with higher slopes
• Higher wall height affords space for loft or attic storage
• Good space for solar panels
• Easy build for beginners

Assembling the Shed Roof’s Substrate

The substrate is the surface where the roofing is applied. In many cases, a roof cover board is the best option for this, and there are several types. They are generally thin substrates that are installed between the insulation and membrane layers of the roof. They can help you avoid blistering in the roof system from the insulation off-gassing when coming into contact with certain adhesives being used for the roof. 

The different types of roof substrates or cover boards are: 

• Plywood/OSB
• Mineral fiber
• Cement
• Wood fiber
• Gypsum fiber
• Gypsum
• High-density polyiso
• Perlite
• Asphaltic

The substrate is installed by being fastened to the structural deck or to an underlying substrate. Many of the best installation techniques include staggering the joists of the cover board in each row and to the joints of the insulation below it. This reduces bridging and gaps between the layers. 

What Kind of Wood is Best For My Shed Roof?

When getting the wood for your shed roof, you should consider a few things:

• The slope of your roof
• The snow load your roof might have to hold 
• A wind that might affect the shed
• What the roof finish will be
• The spacing of the rafters- 12”, 16” or 24”
• The size of your roof
• Your roofing budget

There are different types of plywood that can be used for the roof.

Oriented Strand Board (OSB)

This is a type of sheathing wood that is the least expensive choice. This is made by gluing softwood chips together in a semi-random pattern and comes in sheets, typically 4ft. X 8ft. and 7/16” thick. Even though this will do the job it’s meant to do, OSB is not as strong as plywood and doesn’t last as long when exposed to certain weather conditions. 

Exterior-Grade Plywood (CDX)

Similar to OSB but made to be stronger and be resistant to weather. This is made by gluing thin slices of wood together in layers. Most of the time, ½” thick plywood is good for roofing. The C and D (in CDX) refer to the grades on the plywood and the X means exposure. 

Differences

The biggest difference between these two kinds of wood is how they hold up to water. CDX (exposure) can not withstand water as long as OSB. Therefore, CDX is generally used inside unless it is pressure treated. However, OSB retains water where CDX does not. This can cause the OSB to become damaged. 

OSB is a good choice for sheathing. The glue and resin used to mix the wood chips that make it is less permeable than CDX, making it hold up longer. 

OSB is generally much cheaper than CDX. So, if you want a much more budget-friendly wood, this is the one to choose. 

2×4 vs 2×6 Rafters: What is the Difference?

Depending on the pitch of your shed roof, you will choose between 2×4 or 2×6 rafters. But what is the difference? Simply put, it comes down to what is needed for your shed. The first thing you need to know is if your roof has a slope that is less than or greater than 3:12. This means for every 12 inches of horizontal run, a roof rises 3 inches. For those that are less than 3:12, 2×4 rafters are not strong enough. These are low-pitched roofs and 2×6 rafters should always be the choice of lumber. 

When you want to make a truss you will always use 2x4s webbed together for strength. 

While 2×6 lumber will cost you more money, it can be used for almost any type of shed. They can be spaced further apart than the 2x4s. But, if you live in a place that is not subject to strong winds or heavy snowfall, 2×4 rafters are the way to go. They cannot handle a heavy load like a 2×6 but can give you more versatility with the design of your roof. 

Shed’s Roofing Materials

There are different types of roofing materials you can choose as you prepare to put the finishing touches on your roof. 

• Three-tab shingles – This is the standard and it is also the most inexpensive option for a shed roof. The shingles are easy to install, which makes them a great do-it-yourself option. Many will include a warranty that lasts as long as 30 years. 
• Metal – Metal roofs have a lot of advantages. They are lightweight and they often last longer than other types of roofing materials. They are weather-resistant, which is a great benefit. The only real drawback to metal is that it can be costly, but a lot of these roofing systems have 50+ year warranties. 
• Cedar shakes – When cedar is properly maintained, it can last for as long as 35 years. This material is naturally insect resistant, and it also resists damage from the sun. It has a traditional appearance, and it could be a great option for those looking to pay mid-range prices for their roofing materials. 
• Asphalt Shingles – Architectural shingles are two or more layers of asphalt that have been laminated together. They are much heavier than three-tab shingles, but they carry lifetime warranties. This type of shingle can bring an artistic element to the shed’s roof. They are usually used on residential buildings, which makes them a popular option for sheds too. 
• Fiberglass Mineral Surface Roll Roofing (MSR) – This type of roofing is a glass fiber reinforced asphalt. It is coated with a ceramic granular surface for protection against UV, weather damage, and physical damage. The bottom is coated with a mineral release material. This is generally used for low-sloped buildings such as sheds, porches, and carports. This material is versatile, durable, and cost-effective.
• Board-and-Batten – This roofing and siding application has been around for a long time. It used to be made with wood battens placed over the joints of wood panels. This provided extra protection against bad weather. For roofing jobs, battens were used as drainage paths, allowing the panels to be joined together. Different metals are being used for this now which gives an old-style an updated, contemporary look.
• Polycarbonate Roofing Panel – Polycarbonate is a thermoplastic material that is strong and resilient. A lightweight material, polycarbonate can withstand extreme hot or cold extreme temperatures. It is a good roofing material for sheds, decks, patios, garages, and other smaller structures. This is also a UV resistant option that is affordable and protects against discoloring.

What is the Cheapest Way to Roof a Shed?

The most budget-friendly roofing material is MSR. It is similar to conventional asphalt but comes in wide rolls. Aside from being less expensive than shingles, it is also thinner and easier to install. If your roof has a slope, then roll roofing can be installed with nails. A torch-down method is used for flat roofs. 

How Do You Waterproof a Shed Roof?

Everybody wants to be able to store things in their shed without worrying about the rain or snow getting inside. Weatherproofing the roof is a very important step when building your shed. These are some important steps to keep in mind:

• Step 1: Choose a roof design that lets wet weather fall off it easily, such as a gable or lean-to.
• Step 2: Use felt on the roof before adding shingles. This is just an added layer of protection for the plywood underneath.
• Step 3: Have a suitable overhang. If you don’t, water can be blown back onto the side of the shed and run down the exterior walls.
• Step 4: Repair roof damages immediately.
• Step 5: Add gutters.

Waterproofing your shed roof will help ensure a longer life for your shed. 

How is Your Shed Roof Design Coming Along?

With the right materials, knowledge, and guidance, anyone can frame a shed roof. We hope that this guide has been helpful to you as you build your shed. We would love to hear about how your shed roof is progressing! Let us know in the comments!

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Joseph Truini is a host on the Today’s Homeowner TV show and co-hosts the weekly Today’s Homeowner Radio Show. He has written three best-selling shed-building books and lives in Roxbury, Connecticut.