What is a truss?

Written by LetsBuild

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Trusses are beams, or other pieces of wood, that help create a structure like the base of a roof for a home or other building.  This item is used within the construction industry every day and they have become more advanced over the years.  That is excellent news, because it means that buildings and homes are sturdier than ever before.

Most trusses are either shaped like triangles or pyramids.  The ones shaped like triangles are quite stable, due to the measuring of the angles and the length of the sides of the leg pieces.  Pyramid trusses are not used as often, but you will see some construction companies using them for certain projects.

Types of Trusses


Flat trusses are either designed as top chord bearing or bottom chord bearing and can be used for both simple and multiple spans.  A flat truss is not really flat, because it slopes just slightly to prevent water from pooling up on the roof.  This is important, because if water does collect, the roof can collapse or become damaged.  While this is a very common type of truss, it isn’t as efficient as many of the other types, because the stress on the webs can be bigger.


A gambrel truss looks like a barn roof and has two upper chords, of which one is longer than the other one.  This is the type of truss that is used when you want a living space, or storage space, underneath.  You can also include large windows for the rooms under this type of roof truss.


Bowstring trusses are often massive and arched, but they hold the weight of large buildings wonderfully.  Bowstring trusses are normally used for buildings like airplane hangers and warehouses, basically the ones that need a lot of space inside.  Quite a few beams create the arch and any water that lands on the roof simply runs off, due to the shape of the truss.

Dual Pitched

A dual pitched truss is a triangular truss, making this one of the more conventional truss designs.  Two sides are angled up to the apex and they attach to the horizontal beam below to create the triangle shape.

King Post Truss

A king post truss can be constructed out of wood or a combination of wood and steel, and it just depends on the type of building it is for, as to what materials will be used.

Queen Post Truss

The queen post truss is one of the most versatile trusses in use within the construction industry, which means you can use it for almost any type of building you are working on.

5 Reasons to Use a Truss

You may shy away from trusses in many scenarios, but you must realize that there are many reasons why you should use them.  A few of our favorites include:

  1. Less experienced workers can install trusses, which will save you money since you won’t need to hire more experienced workers to install a different type of roof suspension system.
  2. Certain designs will allow you to have fewer load bearing walls inside, which creates larger open spaces that many people love.
  3. You can save a lot of money on materials when you use a truss, because you can choose lighter materials that cost much less throughout the rest of the building.
  4. It is possible to insulate trusses in only one day, which saves you money in the long term.
  5. Trusses can be constructed off-site and then delivered to the job site and put in place using a crane. This saves you time on the job site and makes the main part of getting the roof on move much faster.

Building Trusses

A design layout is necessary before you begin building a truss and these designs can either be sketched by an architect or designed using software.  Once you have that completed, you must gather all the materials that you will need.

Basic materials include wood, hammers, saws, roof truss plates, and galvanized screws.  It is imperative that you cut the wood, so it matches the specifications of the design that you are working from.

Of course, the wood that you use must also meet the standards that are in place where you are constructing the building.  Most of the time, 2×6’s and 2×8’s are used, but you may need to choose a different size depending on the weight and size of the roof and the requirements you need to work with.

When you attach the galvanized steel connector plates, those pieces create a triangle that you then keep fastened with the galvanized screws.

If you choose to build trusses with a material other than wood, you do have a few options.  Those options include tin, aluminum, and steel.  You must still make sure those materials are cut to the specifications of your design.

Factors to Consider with Trusses

When you are trying to decide on the best type of truss to use for the building you are constructing, you need to base your decision on more than the look of the one you love the most.  If you are unsure which type will hold the weight of the roof, you must consult an experienced truss designer or an architect or engineer.  They can tell you exactly which option will best fit your needs.

If you want to create different sized spaces underneath the trusses, you can also use different truss designs in different parts of the buildings.  This will allow you to customize each room and still have the stability and durability that you need.

Trusses are a major part of any building, which is why it is so important that you know a lot about the different types and how they work.  Without trusses, roofs would not stay in place and the rest of the building can become damaged much easier.

It is true that there are other roofing suspension systems that you can use instead of trusses, but they can be more difficult for many people to install and can take much longer to install as well.  That is why we continue to recommend roof trusses when you are constructing any type of building.