How To Build a Roof (2024 Guide)
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Generally, building a roof isn’t a do-it-yourself (DIY) job. But if you can handle this heavy-duty home project, you stand to save thousands of dollars on new roof installation costs. Our step-by-step guide walks you through how to build a roof safely and correctly, from the initial planning and framing to the material selection involved.
Planning Your Roof
Roofing Material Options
Your roofing material will impact the durability, cost, and roof aesthetic. Below, we’ll review common roofing materials and their pros and cons to help you choose the right roof type.
Framing Your Roof
A roof’s framing provides its structure and shape. You can choose from a variety of layouts for your roof framing plan using either prefabricated trusses or custom rafters.
Rafters
Roof rafters are typically found in stick-frame roofs, which have several rafters arranged side by side that run from the roof ridge to the external wall’s wall plate. Rafters provide a framework that supports the roof deck and roofing materials. Roofers will custom-cut all necessary lumber on-site and use ceiling joists to secure the rafters and connect them to the exterior walls. The ridge board, or beam, provides extra support at the rafter’s highest point.
Rafters are wider than trusses, with common dimensions like 2×8, 2×10, and 2×12. Rafters are easy to insulate and can offer more headroom in your attic, making it easier to perform a conversion if desired. However, installation often requires a specialist who knows how to accurately measure, cut, and install rafters. If you have the expertise and feel comfortable installing rafters on your own, we recommend using an experienced assistant to lift the rafters into place.
Here’s a step-by-step guide on how to measure and cut rafters:
Trusses
Trusses are triangular prefabricated frameworks with three main components—top chords, bottom chords, and web bracing—that form a webbed pattern to support the roof. The webbing structure allows trusses to support heavier roofing materials while using fewer load-bearing walls.
Roof trusses are DIY-friendly, and some include instructions for spacing and fastening. The lumber used is also less expensive than rafters, and installation requires fewer materials than if you were using rafters. However, trusses are heavy and may require a crane to be lifted onto the roof for installation. Trusses also have fewer design options because of their webbing structure and don’t allow for attic conversions.
When installing trusses, use temporary bracing to erect the roof trusses to prevent them from falling over during installation. A common way to brace trusses is by using 2×4 blocks of lumber before installing sheathing.
Here’s how to build temporary bracing for your roof trusses:
- Cut blocks of 2×4 lumber to span from the top chord of one truss to the top chord of another truss.
- Nail the bracing into the top chords while still following the manufacturer’s layout.
- Install diagonal bracing in a “W” pattern.
- Remove the blocks when installing the sheathing.
Roof Pitch Considerations
A roof’s pitch can impact your home’s overall aesthetic, drainage, and the materials used during installation. The roof’s slope also affects its ability to drain water, and not all materials work on roofs with a low pitch.
While asphalt shingles aren’t recommended for roofs with a pitch lower than 2:12, you can use flat roofing materials like ethylene propylene diene monomer (EPDM) rubber for very low angles.
Sheathing Your Roof
Plywood and OSB
Plywood and OSB are both wood panels made by compressing and gluing pieces of wood together. According to the International Association of Certified Home Inspectors, OSB and plywood share many strengths and performance characteristics, but differences in manufacturing processes contribute to each material having its own strengths and weaknesses.
OSB is more uniform and less expensive than plywood, costing about $700 less on a typical 2,400-square-foot house. However, OSB weighs more than plywood, which means it’s more difficult to install and puts more stress on the home’s structure. OSB also swells more when it comes into contact with water and takes longer to dry. This uplifts any materials that lie above OSB and makes decay more likely.
Underlayment
Between the covering and sheathing is the underlayment, which provides an extra layer of protection against water. Underlayment is typically made from asphalt-saturated felt or synthetic materials and covers the entire roof deck. This roofing layer is a vital component and prevents high winds from pushing rain into your home through the roof.
After you install your roof sheathing, install the roof’s underlayment.
- Roll out the underlayment starting at the bottom of the roof all the way to the roof’s peak, overlapping each section as you work.
- Peel off the paper backing and press firmly into place.
- After you install the underlayment over the roof, roll out another layer over the roof’s overhang.
Flashing, Ventilation, and Seals
Proper flashing, ventilation, and seals are necessary in the overall design of your roof to protect the roof’s life span and ensure it functions correctly.
Without proper roof ventilation, warm air and moisture can build in your home and lead to costly repairs, such as mold remediation. Roof ventilation allows air to circulate through your home, which is an essential part of every roof design. There are also plumbing vents that run from the plumbing fixture up through the roof and boots around the vents to waterproof pipe penetrations.
Our Conclusion
Learning how to build a roof can save you thousands of dollars in labor costs, and you may be able to get the job done on your own timeline. However, even a slight misstep can result in potential damage to your roof and cost more in the long run. If you’re unsure of any part of the roofing process, you can always hire a professional to finish the job.
Once you build your new roof, keep up with routine maintenance and inspections to extend your roof’s life span and avoid costly roof repair expenses. Regularly check your roof for leaks and inspect your gutters for signs of wear and tear.
FAQ About How To Build a Roof
How long does it take to build a roof?
How long it takes to build a roof depends on the materials used. Roof replacement typically takes one to 12 days, depending on the roofing materials used, your home’s size, and the weather.
What tools do you need to build a roof?
You’ll need the following tools and materials to build a roof:
- Caulking gun and caulk
- Chalk line
- Circular saw
- Fall protection, such as body harnesses, lanyards, anchor points, roofing brackets, guardrails, safety nets, and safety tethers
- Framing square
- Hammer tacker
- Ladder
- Roofing hammer
- Roofing nail gun and air compressor
- Roofing nails
- Tape measure
- Tarps
- Tool belt
- Utility knife
- Work gloves
Is building your own roof worth it?
Building a roof on your own can save you thousands of dollars, but there are safety risks involved, and some parts of installation require professional expertise. Additionally, if you don’t install your roof properly, you could end up paying more in repair expenses.
What are the steps in framing a roof?
Here are the steps in framing a roof:
- Choose the roof style and design and determine whether you want to build rafters or use pre-fab trusses.
- Determine the desired roof pitch.
- Gather all tools and materials.
- Install roof trusses or rafters.
- Install the ridge beam, if applicable.
- Install roof sheathing.
- Install roof ventilation.
- Install flashing and underlayment.
- Trim and finish.
How much does it cost to build a hip roof?
On average, a hip roof costs $100–$250, while a gable roof costs as much as $800 per truss.
Do I need a permit to build a new roof?
Yes, any structural work to your home requires a permit. Call your local building department to request a building permit for your homebuilding project.
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