How to build roof trusses

How to Build roof trusses? Well, the roof is possibly the most vital part of any building and while you might not really think about it that much, it is a very important aspect of people’s everyday life in this modern world.

Flat trusses are the most common type of roof truss, accounting for 30% of the market share. They are simple and easy to build, and they are a good choice for homes with low-slope roofs. Gambrel trusses are also a popular choice, accounting for 20% of the market share. They have two slopes, which gives them more headroom and storage space than flat trusses. Bowstring roof trusses are less common, accounting for 15% of the market share. They are a good choice for homes with long spans, such as barns or warehouses. Dual-pitched roof trusses are the least common type of roof truss, accounting for 35% of the market share. They are a good choice for homes with steep roofs, such as A-frame homes.



Topping off every establishment, the roof protects you and all your valuable possessions from the outside world and its different elements.

Roof trusses form the stability and core for a roof of a home or commercial building. For roofs, the truss is being used to frame the actual shape itself. The truss is commonly pre-fabricated from wood and is what holds up the roof.

Most of the typical configurations of roof trusses that can be found today are named based accordingly to their shape, like Gable, M, Scissors and W truss.

Once the trusses are up, these will be fastened with  metal sheets before being covered by a plywood sheet.

When a roof truss is not constructed, it can be difficult to properly frame the roof of a house or building.

The angles needed can be very hard to measure and frame properly. Lastly, if you would like to free yourself from the expenses and headache caused by building a strong and durable roof, it is highly recommended to build a truss.

Today, there are many home builders who choose to order the prefabricated roof trusses from manufacturers and have these delivered to the building site because building trusses can be labor intensive and the prefabricated ones will help them save time, money, and materials.

Types of Roof Trusses

Aside from the common wood roof trusses, there are still other types that are built using different materials to effectively support and distribute the load to the walls.

  • Flat Trusses

The flat truss can be designed as bottom or top chord bearing or for multiple and simple spans. This can be cantilevered at one or both ends.

A flat truss is not necessarily flat, as it slightly slopes to prevent the pooling of water on the roof and prevents the damaging or collapsing of the entire structure.

While among the most common types, this truss is considered as less efficient because the stress on the webs of the flat trusses is greater compared to other types.

  • Gambrel Trusses

The gambrel roof truss resembles the appearance of a barn roof. It has two upper chords, with  one longer than the other. These two chords meet at the truss’s apex. Since it has steep sides, there is sufficient room for a living space below the roof or can be used as a storage space in the attic.

The gambrel roof truss in homes lets you include an upper floor below the roof. There is also an extra room for the large windows that can make it look brighter inside the house.

  • Bowstring roof trusses

Usually large and arched, the bowstring trusses give support to the building’s weight, such as the aircraft hangars and the warehouses that require a lot of open space inside.

Several beams make up the arch, while the roof outside is made up of metal sheets or other materials. The water can run off easily from this kind of roofs and a ridge cap is not required.

  • Dual pitched trusses

Its conventional triangular truss design is that the two sides are sloping up to the apex above, with the struts known as the upper chords leading down from it. These are  attached to the horizontal beam, thus making up the triangle’s base.

Typically, the upper chords have different lengths in this particular type of truss that make the apex off-center. It allows a lot of open space unobstructed by the poles for support.


The very first step for building roof trusses is to prepare a design layout that can be sketched by a professional architect or can also be done by using a software that is specifically meant to design a roof truss.

The second step in building a roof truss is to prepare the materials needed. These will include wood, a hammer, a saw,  roof truss plates made from galvanized steel and galvanized screws of 1 ½ inches.

The wood needs to be cut based on the size of the roof and specifications in the design. It must also adhere to all the local building standards and codes. Most of the time, the sizes of the wood used range from 2×6 and 2×8 even though its thickness can be based on the weight that it will support and the overall size of the roof.

It is crucial that you use connector plates made from galvanized steel. It is a kind of steel that has a zinc coating and can prevent the occurrence of any corrosion.

The plates and the wood will join together in the shape of a triangle and will then be fastened together using  galvanized steel screws, which aren’t shorter than 1 ½ inches in their length. Depending on the wood’s thickness, you might also want to use thicker screws.

If you want to build a roof truss with the use of other materials aside from wood, like steel, aluminum or tin, you will need to cut the material based also on the roof size and design specifications, just like with wood trusses.

The method of learning how to build the roof trusses might be a bit more complicated compared to other methods since you will need to take some extra steps of cutting the gussets that are used for giving the needed extra support and strength to the truss.

When building your roof trusses, you need to calculate the right strength for the base of the roofing. This is important because an inappropriate strength can cause the structure to warp or collapse.


If you want to know how to build roof trusses for a garage, you must ask a professional about the right support of the roof as well as its weight.

Trusses are utilized for stabilizing and supporting the walls, particularly in huge buildings that have more than one to two stories.

Usually, roof trusses are triangular and can be installed easily. Another advantage of roof trusses for a garage roof is that they are practical and can be used with several materials.

Learning how to install roof trusses for a garage roof isn’t hard, particular if you follow particular hints and tips.

  • Cutting the Timbers

The first thing you should do when building roof trusses is to cut timber panels to the garage roof’s size. Measure the roof’s span and check with the building project and plan.

Before you buy timber panels, you must also take into consideration  the weight they’ll be supporting. The reason behind it is that this will help you know their thickness. More often than not, you will have to purchase 2×8” timber panels and cut them to the size if required.

  • Securing Timber Panels Together

Utilize the connector plates when securing timber panels and creating a triangular shape. For securing the panels and maintaining the triangular shape, use screws.

  • Adding the Brace

For dissecting the triangle center, use a brace. If you require sturdy trusses that will provide load support, you must also use extra supports from the bottom, as well as up to the trusses’ top part. With this, roof trusses will bear a much heavier load easily.

  • Securing the Trusses

Another thing you should do is to secure the roof truss to the frame. See to it that you ensure proper overhang. If you’re not sure what’s the right overhang, you must check the garage roof’s size and roof pitch. You may also consult with a mechanic or an architect who can give you recommendations about the measurements.

  • Attach the Roof Trusses

When attaching roof trusses to roof frame, make use of deck screws. The majority of professionals would suggest or recommend you to brace trusses.

  • Extra Tips to Remember

Don’t begin with any constructing project yet if you still haven’t checked the local and building code. You have to ensure safety before you build anything new onto your garage and house. Your building code and project will also provide you an idea of the timber size you must purchase.

In several cases, building codes don’t let you complete any building projects without the involvement of a mechanic or a professional. Roof trusses may be crucial for a garage’s integrity and stability. Roof trusses will hold of most of the load and will ensure the garage’s stability.


The roof trusses for sheds are one of the most vital pieces to design. These consist of 2 rafters that will hold up the structure’s roof. Once completed, the roof trusses are installed and lifted onto the top part of shed frames.

The trusses you require may depend upon the shed’s length. The longer your shed is, the more roof trusses you will have to make. The good thing about roof trusses is that they are simple to construct.


Step #1

Begin by determining the measurements of the roof’s slope. This will be the rafters’ length. If your roof has a long slope on one of the shed’s side, one of your rafters should be longer.

So, know the number of the roof trusses you’ll need, then double the number for you to acquire the number of the rafters you’ll need when building the roof trusses.

Step #2

Cut the rafters from 2×4 piece of wood. Cut it to the length you require and add the plumb cut to its ends.  This plumb cut should be a 45-degree angle cut.

Step #3

Cut the bottom cord of the roof trusses.

Step #4

Make the gussets, which are the  half-inch thick plywood pieces that will  cover the 3 ends of the roof trusses.

Step #5

Start assembling the trusses. You can assemble these on the floor of the shed being constructed.

Step #6

To ensure that the rafter and the bottom chord fit together and are attached securely, you can use stop blocks and end blocks.

Step #7

Once assembled, start nailing and gluing the gussets to the corners. When the glue dries, secure the truss by placing it between the blocks. Then, attach the other three gussets.

Why Use a Roof Truss?

A roof truss is used in various applications where a strong and lightweight structure is needed. It is also used extensively in buildings, bridges, space-based constructions, and radio and TV towers.

The majority of home builders order a prefabricated roof truss from the manufacturer and have these delivered to the building site due to the fact that building roof trusses is said to be labor intensive and the prefabricated ones can save materials, money, and time.

Benefits of Using Roof Trusses

  • Carpenters who have less experience and can set trusses will require low labor costs.
  • Lesser interior load is required because of the longer free span of trusses.
  • Shorter lengths of the stock 2x4s are utilized for building trusses, which reduces the price of the materials.
  • Trusses can be set in one day. This means that your home’s interior will only be exposed to any weather conditions for a short period of time.
  • Structural engineers certify and design roof trusses.

Roof Truss – Factors to Consider

When you are considering roof trusses for your house, whether you want to know how to build roof trusses for a shed or a garage, you should not just have based your choice on the looks alone.

If you are having a hard time choosing the right type of truss for your roof, an experienced truss designer, engineer or architect can help you determine the best design suited for your requirements.

Professionals with training particular to roof trusses can make the most use of the rooms in your house, providing it has the right amount of space you’re searching for.

For instance, a different kind of roof truss design may be used in different areas of your house, making it possible for you to customize the rooms in your house, while maintaining the same look of your exterior.

Another thing you should be aware of is that several roof trusses can be practical for weather in certain areas, yet may not accommodate the building’s desired design specifications. Good engineers and architects will also consider the design of the building.

Last update on 2023-07-04 / Affiliate links / Images from Amazon Product Advertising API

Founder & Editor

Hi, I’m Jim. I was a roofing constructor for 20 years, before deciding to start and gather the best content about roofing. I love woodworking and construction and it was only natural for me to start this passion project of mine. Thank you for visitng.