Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.
Trusses are structures that support the weight of a roof. They’re typically wooden frames upon which the rest of the roof is built. Trusses are easy to install but must also be maintained and add a lot of weight to the construction. Is it even possible to build a roof without trusses?
It is possible to build a roof without trusses. In the past, roofs were often constructed without using trusses. Flat roofs or roofs with a single slope are built without trusses.
Next, we’ll explore which roofs can be built without trusses. By the end of this article, you’ll better understand how roofs are made and your options when building one.
Are Trusses Necessary?
Trusses can be found on roofs across the world. They hold the roof in place and support the tiles, shingles, or roofing placed on top. Being so common, people wonder if trusses are entirely necessary or rather an optional feature.
Trusses are not necessary for every type of roof design. Flat roofs, for instance, don’t require trusses to hold firm. Rafters can be used in place of trusses in the case of ordinary roofs.
While trusses are not necessary for roof construction, four out of five new homes in the US are built with trusses in the roof. The reason is that trusses are solid and durable, produce less waste than their alternatives, and ensure long-term rigidity for the roof.
However, trusses can’t be used in a flat roof or a single-sloped roof because of their shape. Trusses are also not practical if you plan to expand the roof in the future. If you want to be able to add extensions or change the structure of your roof, rafters are a better option than trusses.
What Types of Roofs are Built Without Trusses?
As you already know, building a roof without trusses is perfectly possible. However, it’s not just an alternative: many roofs are typically built without trusses. These roofs have other features that allow them to have structural integrity without adding trusses.
Some types of roofs built without trusses are flat roofs, domed roofs, single-sloped roofs, and roofs built using rafters. Millions of roofs across the world are built using these styles. Trusses are only applicable to roofs that have a triangular shape.
In the past, roofs were usually constructed without trusses. Roofing trusses only became popular in the 1950s. Before this, roofs were built primarily using rafters as structural support.
Rafters are made of planks that slope down from the top of the roof, with a beam running through the middle of them. Because of their versatility, you can see them on almost any type of roof. Rafters are often made of wood but can also be found in other materials.
What are the Disadvantages of Using Trusses in a Roof?
Trusses aren’t your only choice when building a new roof. Using trusses has some disadvantages that may make you opt for an alternative. Let’s explore in detail what these disadvantages are.
Here are the disadvantages of using trusses on a roof:
- Requires a lot of maintenance
- Can be heavy
- Wood and timber degrade over time
Requires a Lot of Maintenance
One of the most significant drawbacks to choosing trusses for your roof is their maintenance needs.
Trusses carry a lot of weight after the roof has been laid on top. As a result, components in the truss are vulnerable to wear and tear. You will likely need to hire an expert for routine maintenance every year or so.
Can Be Heavy
When trusses support a large roof in a more prominent building, the truss itself may end up being quite heavy by itself. When this is the case, trusses may require additional structural support to ensure that they and the surrounding structures remain strong. All that extra weight results in added costs.
Timber Degrades Over Time
Another disadvantage to choosing trusses for your roof comes from their material. Trusses are typically made from timber. Like any wood, timber is prone to rot when exposed to moisture or water. A small leak could cause the trusses in your roof to severely weaken, resulting in expensive repairs and replacements.
What are the Advantages of Using Trusses in a Roof?
Here are the advantages of using trusses on a roof:
- Straightforward installation process
- It’s cheaper than its alternatives
- It’s less wasteful
See below for more information on the benefits of using trusses:
Straightforward Installation Process
Trusses are pre-assembled to fit a design before arriving at the building site. As a result, a professional roofer can quickly and easily install trusses without the need for frames or other heavy machinery. This reduces the time needed to build the new roof and saves on labor expenses.
It’s Cheaper Than Alternatives
Trusses are typically much more cost-effective than rafters or beams. They use fewer materials and come pre-assembled to the construction site. This allows you to save a lot of money that would otherwise go to labor and more expensive materials. There are very few instances where trusses may end up being more expensive than their alternatives.
It’s Less Wasteful
Trusses are pre-assembled before arriving at a construction site, so they don’t require any adjustments. In comparison, rafters are measured and cut on location to fit the roof. Because pieces are removed during installation, rafters produce more waste than their pre-assembled counterparts.
Trusses are the most common supporting structure found in new roofs across the US. However, you don’t need trusses to support your roof. Flat roofs, don’t roofs, single-sloped roofs, and roofs using rafters are all common examples of roofs without trusses.
Trusses offer a convenient, durable, and cost-effective support structure for roofs. However, trusses can also require high maintenance and become heavy on themselves. They are also prone to rotting, which can add expenses down the line.
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