Guide to roof trusses|PdD

Did you know that the roof of your new home will be one of the biggest architectural and structural challenges? Its implementation is a milestone in the process of creating the entire building. Perhaps you already know perfectly well what type of roof will crown the walls of your house. You can imagine the sheen of the tiles and the smoke rising from the chimney... You feel the security of a solid structure overhead. To make this vision quickly become a reality, think about solid roof trusses. It is the framework hidden under the tiles that will be the biggest challenge for builders and an important condition for the success of the entire project. Check out what options the construction market offers at the moment and which one is best for you!

Roof trusses – what are they?

Wooden trusses are traditional elements of roof construction, but in recent years the way they are made and their role have changed significantly. In a general sense, a truss is a component of the roof frame, and its task is to keep it in shape and provide load-bearing capacity. Integral elements of trusses are rafters, beams and columns, connected to each other in a permanent and irreversible way. The resulting three-dimensional structures form the roof truss, a skeleton that rises above the entire building.

The latest generation of trusses are prefabricated, which means they are created in factories using precision technology. This fact is groundbreaking for the entire roof erection process. Why?

The truss is a three-dimensional element of the roof structure. Its task is to transfer loads from the roofing to the ceiling and load-bearing walls.

Photo by Avel Chuklanov © Unsplash

Traditional wood trusses vs. prefabricated trusses

To appreciate the advantages of prefabricated roof trusses, you need to learn about the traditional method of erecting a roof and imagine all the difficulties involved. The task of constructing the roof is entrusted to the roofing team, which enters the site after the construction of the upper floors is completed. At this point, the material must already be on site: properly prepared and dried wood. Each element of the construction of a traditional roof truss is made on site using hand-held roofing tools. The implementation of the truss is labor-intensive, requiring precise cutting of each board and can take up to several weeks. The season, weather conditions and the proper condition of the sawn timber, which must remain dry, are also important.

When is it worth choosing traditional roofing methods? This is beneficial almost exclusively in the design of complex, multi-slope roofs, the factory production of which can significantly increase the costs.

Each element of a traditional roof truss is made by hand using carpentry tools. It can take up to several weeks to erect the entire roof structure.

Photo by Greyson Joralemon © Unsplash

How does the production of prefabricated roof trusses proceed?

It is worth noting at the outset that the entire process of manufacturing roof trusses (from the idea to the elements ready for assembly) takes place in the factory halls. This is vividly described by Jacek Wiśniewski, a wood technology specialist with twenty-five years of experience. Let's try to isolate the key stages of truss production:

It all starts with the roof design, which goes to the roof truss manufacturer for an estimate.
Once the estimate is approved, an accurate production design is prepared.
It is up to the manufacturer to purchase the lumber (usually C24 grade pine wood),
The wood is cut using digitally controlled saws and then assembled into individual trusses.
The next stage is impregnation, which protects the surface of the wood against fire, mold, fungi and insects.
The impregnated parts go to the press, where they are assembled into complete trusses.

The entire production process is automated, which guarantees perfect repeatability and accuracy in the execution of each element. The wooden roof trusses are then packed onto transport platforms and transported to the construction site.

Prefabricated roof trusses and their unique assembly

If you buy a prefabricated roof truss, along with its manufacture you can also order installation. It is worth to choose this service, as it is a condition for obtaining a warranty on the roof structure. A properly trained factory crew arrives on site with the trusses and gets to work right away. The entire process should close in a period of one to several days.

Interestingly, not a single nail is used in the installation of the prefabricated roof truss. The unique truss connection system uses Mitek barbed plates. This enables efficient assembly with millimeter precision. Is the roof skeleton formed in a dozen hours stable and safe? Here it is worth noting that the scaffolding of prefabricated trusses is spaced more densely than in the case of traditional trusses. The resulting truss guarantees a stable structure that perfectly fulfills its role: it transfers stresses from the roofing to the load-bearing walls.

Advantages and disadvantages of prefabricated trusses

With these innovative products, it is much easier to point out the advantages. So let's start with them:

timber lattice trusses are designed and manufactured using modern technologies — this guarantees precision unattainable even for an experienced carpenter,
quick installation of trusses, even in the autumn-winter season, significantly reduces construction time,
trusses fastened with barbed plates are much lighter. That makes it easier to transport them and operate the crane during installation. It also reduces the load on load-bearing walls,
comprehensive preparation of lumber in the production plant eliminates the problem of excessive moisture in the wood,
prefabricated roof trusses have an extremely wide range of applications: from single-family housing to industrial halls.

So, do roof trusses have any disadvantages? These may include the high cost of this technology when making complex multi-pitched roofs. However, with the increasing popularity of prefabricated products and growing competition, the prices of trusses are slowly equaling those of traditional roof assembly methods.

Trusses fastened with barbed plates are much lighter than those assembled with nails. This has an impact on their transportation, installation and load on load-bearing walls.

Photo: Ulrik Trappschuh © Pexels

Roof trusses for the truss of a single-family house

Let's return for a moment to the use of wooden roof trusses in residential construction. The prefabricated truss structure allows roofs with spans of up to 30 meters to be covered without the need to install additional reinforcing elements. What does this mean in practice for the investor and owner of a single-family house under construction? If your project involves a house with a habitable attic, you can get free space without restrictive load-bearing columns. This is also good news for the architect: scaffolding with lightweight lattice trusses allows you to eliminate the concrete ceiling and slim down the foundation and load-bearing walls of the building. Thanks to the fact that the interior walls are no longer load-bearing, you can freely plan the space on the first floor and attic of your house.

Lightweight lattice truss scaffolding allows you to slim down the foundation and load-bearing walls of the building. It is an ideal solution for single-family houses with a usable attic.

How much does a truss roof cost?

Prefabricated roof structures are slowly but consistently conquering the market, and there are many indications that they will become the future of modern construction. Importantly, this technology carries the potential to significantly reduce the cost of making a safe and sound roof. The price of the service including installation may seem significant at first glance, but it is worth analyzing all the savings that the choice of prefabricated products offers:

the possibility of eliminating a heavy and expensive concrete floor,
the building's foundation can be less massive, and interior walls can be made with cheaper technology,
great savings in the case of construction of single and gable roofs of simple construction,
less consumption of wood with increased load-bearing capacity,
the manufacturer prepares, impregnates and delivers certified wood, which excludes its theft or destruction at the construction site,
rapid erection of the entire roof structure — no losses due to the unreliability of the roofing team.

As you can see, the design of a house with a timber-frame roof can generate savings within a variety of construction materials and services. However, the question „how much do roof trusses cost” can also be answered more specifically. Manufacturers of prefabricated products declare that the cost of the implementation of the roof structure, including installation, is within the range of 80-100 PLN/m².

Do you need up-to-date information on the complex realization of the roof with its insulation and covering? Visit the roofs and roof accessories category for more interesting articles!

Roof trusses are a big money saver when it comes to the realization of simple, single and gabled roof structures.

Bottom line: prefabricated structural elements are the future of construction! No wonder, trusses designed with mathematical precision guarantee a solid roof structure for decades to come. If you trust the latest technology now, you'll be sleeping under your own roof sooner than you think. What's more, you'll enjoy a lightweight and secure structure that opens up entirely new possibilities.

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