How to Build and Install Metal Trusses in 4 Steps

Raise the roof with the right framework

Metal trusses on a house construction site
Photo: sbw19 / Adobe Stock
Metal trusses on a house construction site
Photo: sbw19 / Adobe Stock
SKILL LEVEL
Expert
COMPLETION TIME
14 days
COST
$1,000+
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What you'll need:
TOOLS
  • Metal cutter (optional)
  • Welding torch
  • Ladder
  • Man lift (optional)
  • Safety gear
SUPPLIES
  • Prefabricated metal trusses
  • Truss head lath screws

Roof trusses are the backbone of your roof, giving it structure, shape, and durability. When it comes to selecting the right material, metal roof trusses are one option some homeowners choose for projects like sheds, garages, and pole barns. While the cost of metal trusses is nearly double that of wood trusses, metal can bear a higher load than wood. This means if you are planning a bigger structure like a large livestock barn, you can have a wider span with more space in between supports. Below, you’ll find the steps you need to take on this project.

Before Starting to Build and Install Metal Trusses

Trusses form the framework for your roof, giving it shape and support. Unless you are an experienced roofer or builder, this probably isn’t a DIY project for the weekend. Roof trusses impact the function of your roof, so any mistakes could result in significant (and costly) problems down the road. Not to mention, the necessary know-how needed for successful and safe welding. If you have a solid understanding of how the parts of a roof fit together and a background in building, the steps below outline what's involved in building metal trusses.

  1. Purchase the Trusses

    Purchasing prefabricated trusses is your best bet to ensure they fit together correctly and avoid having to do any metal cutting. You can also buy pre-cut trusses from a building materials manufacturer. Standard metal trusses come in several different sizes, ranging from 20 inches to 100 inches in width in a variety of slopes based on your roof pitch.

  2. Assemble the Trusses

    3 main parts of a truss, including top chord, runner, and webbing

    When your ordered trusses arrive, they will likely come already assembled and ready to attach to the roof of your building, or they may come in pieces that need to be assembled. Trusses have three main parts:

    • Top chord: The two metal bars set in a triangle shape that gives a truss its peak (also called rafters)

    • Runner: The metal bar that runs horizontally at the bottom of the triangle shape

    • Webbing: The metal bars that go in the middle of the truss and give it support

    Since the pieces are metal-on-metal, the metal bars will need to be welded together to form the trusses if they're not pre-assembled.

  3. Weld the Truss Together

    There are several different welding methods pros use, including metal inert gas (MIG) welding, tungsten inert gas (TIG) welding, stick welding, gas welding, and forge welding, but MIG tends to be the easiest. When welding together steel trusses, any method can be used besides TIG.

    Without the proper safety equipment and qualifications, it’s best not to try welding metal yourself and instead hire a qualified welder or purchase prefabricated metal trusses. According to HomeAdvisor, hiring a welder costs around $13 to $15 per pound of steel involved in the project.

  4. Lift and Hang the Trusses on the Roof

    Detail of metal trusses
    Photo: Phoompiphat / Adobe Stock

    Once the trusses are assembled securely, you’ll need to hoist them onto the building structure and place them on the wood support beams. Once they are in place, secure the trusses to the structure using bolts.

How Much Does It Cost to Build Metal Trusses Yourself vs. Hire a Pro?

You may be looking at all of these steps and thinking it’s best to hire someone to take it off of your hands instead. Here’s some additional information to help you make the best decision for your home project.

DIY Truss-Building

Roofing labor costs about $50 to $75 per hour, so by building metal trusses yourself, you’ll likely save on that cost. However, this project is not an easy DIY, and you’ll need to research the following to ensure the project is done safely and correctly:

  • Acquire all necessary permits

  • Purchase safety gear like gloves, safety glasses, a hard hat, and a welding mask

  • Ensure that you perform the work in mild weather, not during rain, snow, or high winds

Hiring a Roofing Pro

Hiring a local metal roof contractor is a much safer bet. While it might save you money on labor in the short term to try to build metal trusses yourself, it will probably actually save you more in the long run if you hire a pro. That way, you won’t be paying for roof repairs later or the cost of a replacement roof due to any mistakes made in the building process.

Plus, doing this job yourself may void your roof’s manufacturer’s warranty, meaning you’ll face high costs if your roof gets damaged in the future.

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