Drawings and diagrams of the rafter system of a gable roof

Anyone working on building or remodeling projects needs to understand the gable roof’s rafter system. This important structural component creates the framework that bears the weight and shape of the roof. Building professionals can learn how to effectively distribute loads and guarantee the stability of the roof over time by examining drawings and diagrams of the rafter system.

A sequence of triangular trusses or beams that slope from the ridge, the highest point of the roof, to the eaves, the edges where the roof meets the walls, make up the typical rafter system. In addition to offering structural support, these rafters establish the pitch of the roof, which has an impact on drainage and aesthetics. To build a strong framework that can handle a range of loads and weather, each rafter is expertly positioned and angled.

The rafter system’s drawings and diagrams provide intricate visual representations of these structural components. They show the connections between rafters and wall plates, collar ties, and ridge boards, among other parts. These diagrams help builders precisely plan and carry out the building process, guaranteeing that every rafter is placed in the right place and that the entire roof system complies with engineering and architectural requirements.

In addition, these drawings are essential means of communication for construction teams, engineers, and architects. They ensure that all parties involved understand the requirements of the project by communicating important details about dimensions, angles, and material specifications. Professionals can work together efficiently and troubleshoot possible problems both before and during the construction process by consulting these comprehensive diagrams.

Construction device for a gable roof

For two-pitch roofs, rafter load-bearing structures can be layered or suspended. These varieties vary not only in how they are put together and secured, but also in that they are made to fit specific kinds of homes based on their dimensions.

A ridge girder connects the two inclined planes/slopes at their top point to form the triangular rafter system of a gable roof.

The following are the primary component modules of the traditional rafter system:

1. Mauerlat – located in the lower base, is the connecting link between the load-bearing walls and the roof. It is a beam on which the rafter legs and other rafter elements rest.
2. Rafter legs – often wooden, but in the construction of large buildings, metal elements are used. These are the main parts of the rafter system, they form a slope angle and create two slopes. The rafters must be made of high-quality material, durable and strong, as they provide the main support for arranging the roofing pie and laying the finishing coating.
3. Ridge or ridge beam – an outer, horizontal connecting rib on which the upper parts of the rafter legs are fixed.
4. Puffs – elements that connect opposite rafters crosswise provide rigidity and strength.
5. Side purlins – additionally support the rafters.
6. Lezhny – evenly redistribute the load from the roof structure. These are bars that are installed along the Mauerlat.
7. Racks – “relieve” the load from the purlins, directing them to the beds.

Filly elements are small additional boards that "continue" the rafter leg and are used when arranging overhangs. The house’s walls will be shielded from the effects of precipitation by the roof overhang. The foundation and walls of the house will be more consistently shielded from inclement weather the farther the roof overhang extends from the wall.

Experts create a project and drawings that list every component of the truss structure when planning a gable roof.

The technical documentation explains in various projections how to fix the mounting modules and rafters. The order of each installation step is taken into consideration when creating the drawings.

Layered type

When building a large house with multiple rows of walls, the universal structure of the layered type becomes essential. When building a house wider than 6 meters, extra supports are placed on the internal load-bearing walls, such as one in the middle or two parallel walls, to keep the rafters from sagging.

The building’s dimensions can reach 16–18 meters, and more supporting components are required. There shouldn’t be more than 7-8 meters between supports. It is advised to put at least one support in the center if the roof width is less than 10 meters. From the ridge beam to the load-bearing wall, the load from the roof travels through the installed support beam.

Experts advise keeping the rafter pitch between 110 and 120 cm. For safe operation, scaffolding needs to be installed before installing a layered rafter system.

When assembling a layered rafter system, a Mauerlat must be present. Struts are used to divide support posts and purlins. They ensure maximum stability and rigidity of the entire structure and lessen the load on the purlins.

Another significant function of the struts is to reduce the load on the rafters and allow the construction site’s overlapped width to be expanded. Generally speaking, a rafter leg with a length greater than the typical 6 m (timber) has a composite structure.

There are multiple ways to arrange rafters in a layered type:

Non-thrust rafters

There is no increased pressure on the walls—only bending of the rafters is experienced. One of three device options is available to you:

1. The support for the rafters is a classic Mauerlat. It can also be hemmed with support bars. A tooth cut is used for fixation. Use additional fasteners with special durable clamps. The upper part of the rafters is laid on the ridge, secured with a “sliding support”. The upper holes are fixed.
2. The lower parts of the rafters are fixed to the Mauerlat with a movable fastener “slider”. Reinforcement on a piece of wood with a strong nail, or a metal strip on top is important. In the ridge part, the rafters are secured in pairs with holes, or each leg to the purlin separately.
3. In this method, the ridge purlin and rafter legs are securely fixed into one piece. Thin bars or slats are stuffed parallel to the ridge on both sides. Here the rafters bend minimally.

Less people choose the third, more labor-intensive option.

Spacers

While it is the same as the previous option, this one has unique features. The bursting load and weight are transferred to the building’s load-bearing walls by the incredibly rigid and stationary fastening of the rafter leg.

The Mauerlat needs to be fastened as securely as possible to the home’s walls in order to install a spacer layered rafter system. A belt of reinforced concrete can be installed around the walls’ perimeter.

With struts

The brace is referred to as the rafters’ third leg, or sub-rafter. Compression is provided by this 45-degree angled device. The brace angle’s cut needs to precisely match the given value. Ascertain the load on the compression in order to choose the beam’s cross-section.

On the rafter beams

Select two rafter systems if the house has two load-bearing walls:

• Beams are laid along the long roof area;
• there are racks under them;
• beams lie on the racks.

Within the house, benches and walls are used for extra support. The racks are positioned beneath the rafters when there are no purlins. You can also use contractions that gradually take compression loads in the lower zone. Steel plates are used to join and secure the rafters at the top. A spreader in place of a skate.

Hanging

For small country homes or cottages with walls no longer than six meters, this kind of rafter system is advised.

Variation in the design:

• the rafter legs rest on the side walls of the house;
• the tightening connects the “heels” of adjacent rafter legs (truss);
• instead of strings, ceilings in the form of beams are often used, especially when constructing attics;
• In the upper part of the rafters rest on each other.

This more straightforward version is suitable for summertime seasonal cottages with a "cold roof."

Puffs are made from wood or metal fasteners. The tie’s attachment to the rafter system should be stronger the higher it is positioned. The bursting load from the wall rafters is lessened by tightening.

There are various options available for the hanging type rafter system:

Triangular arch on three hinges

The most basic design is a triangle, with bending loads applied to the upper sides. The cornice assembly can be fastened with plate fasteners or equipped with perpendicular notches.

Option with reinforcement

An antiquated technique that is no longer in use for industrial facilities. The drawstring on the ridge, the wooden pendant (headstock), and the metal pendant (strand) are its differences.

With raised drawstring

Using it to organize an attic is advised. There is a drawstring at the top of the triangular three-joint arch with raised drawstring. The tensile load increases as it is raised higher. The rafters are secured to the Mauerlat like a slider in this dependable and stable option.

The rafter legs’ edges have to extend past the building’s exterior walls. Tension from sagging is counterbalanced by suspension.

Arch in the form of a triangle on three hinges with a crossbar

Large bursting loads are the reason the system is selected. In the upper zone, a crossbar is installed, and at the bottom, a tightening is fixed. In this instance, strengthening the mauerlat on the walls is not required. The structure is stiff and incredibly strong.

Complicated with struts and headstock

An efficient technique for extremely long rafter legs. Sagging is eliminated by the supports known as struts. Since there is no load-bearing wall in the hanging system, the strut emphasis is placed in the headstock.

The upper zone bears the majority of the cargo load. Pulling down on the headstock clamp is a component-based tightening that lowers the ridge assembly.

Subtleties of leg fastening

There are various techniques for fixing rafter legs to the top and bottom of the system.

Bottom part

The rafter leg is fastened either directly to the ceilings or to the Mauerlat.

There are two methods for fastening rafters to the Mauerlat:

• rigid – for the layered type, the rafter leg is rigidly secured by a notch or additional beam and fasteners;
• sliding – “sled” fasteners or corners with oval holes for fastening, allow the rafter leg to move slightly.

Fasteners include different types of nails, studs with metal overlays, staples with nails, and nailed steel strips with rows of teeth. appropriate bolts, screws, and brackets.

Top part

Additionally, there are two ways to fasten the rafters in the ridge section:

• end-to-end – the top of the rafter is cut at the required angle and two opposite legs rest against the joints at the cutting points, possibly connecting with fasteners (for example, 15 cm nails) at an angle;
• overlap – fastening between the side planes with studs;
• to the ridge – the fasteners are made directly on the ridge beam, the rafters do not rest on each other.

Fastening components need to have an anti-corrosion coating and be the same thickness as the modules they are fastening.

How to avoid complex calculations?

To avoid delving into intricate engineering computations, where an unskilled individual might commit an error, you can reach out to experts or utilize a specialized online construction calculator that provides an accurate estimate based on the house’s entered specifications.

The necessary questions will also be addressed by using the GOST technical literature tables.

Which one is more cost effective??

You can select the option that will work best for your gable roof’s configuration as well as from an economical standpoint when designing the rafter system.

Therefore, a hanging rafter system is recommended for small country houses, summer cottages, terraces, or gazebos with small dimensions and wall lengths up to 6 m. The simplest, fastest assembly and the least amount of component modules are used, which lowers expenses. Consider a triangle arch with three hinges.

Professionals advise designing a more intricate but robust, layered rafter system for cottages and buildings with large dimensions.

The non-thrust design is the most straightforward, but if this is insufficient, you should choose a particular solution that will guarantee longevity and wear resistance, even if it means paying a little bit more.

Anyone involved in building or renovating a gable roof must be able to read the drawings and diagrams of the rafter system. These schematics offer a clear road map for how the structure of the roof supports and disperses weight. They help builders ensure the stability and integrity of the roof by specifying the rafters’ lengths, angles, and connections.

The rafters, which are the main structural components that make up the roof’s framework, are at the center of these diagrams. They descend to the eaves, or the edges of the roof that protrude over the walls, from the ridge, which is the highest point where two roof slopes converge. In addition to defining the roof’s shape, the rafter system establishes how strong it is against loads like wind, snow, and the weight of the roofing materials.

These drawings also show how rafters connect to other important elements such as the ridge board, which runs horizontally along the roof’s peak and supports the rafters’ upper ends. They also show how to install ceiling joists or collar ties, which keep the roof from collapsing under the weight placed on it.

Before construction starts, builders can plan solutions and anticipate problems by examining these diagrams. They make it possible to precisely calculate the materials required and guarantee adherence to building codes, which specify safe and efficient roof design. In the end, knowing these drawings well enables builders to produce long-lasting, practical, and aesthetically beautiful gable roofs.

Anyone working on building or renovating a gable roof must comprehend the drawings and diagrams of the rafter system. These graphic aids offer a clear road map for constructing a sturdy roof, detailing the exact location and joining of every part. You can guarantee accuracy in measurements, cuts, and installations by becoming familiar with these diagrams, which will result in a roof that is long-lasting and attractive. The fundamental components of gable roof rafter drawings will be dissected in this post, making them understandable and approachable for both experts and do-it-yourselfers.

Video on the topic

Rafter system plan. Part 1

Gable roof truss system/Gable roof rafter system WITHOUT ARMOUS BELT