Trusses are pre-fabricated, triangulated wooden structures used to support the roof. … You can span a large distance with a truss and the truss transmits all of the weight to the exterior walls. Therefore, none of the interior walls are “load-bearing,” so they can go anywhere and are easily moved later.
How are rafters supported?
In homes with flat ceilings and an attic space, the bottoms of opposing rafters should be fastened together with ceiling joists, which form “rafter ties.” When rafters have been installed perpendicular to the ceiling joists, rafter ties typically rest on top of the ceiling joists.
What are the different components of the supporting structure of a roof?
Parts of a Roofing Structure
- Rafter. Image link: https://torange.biz/rafter-system-roof-4013. …
- Collar Beam. Collar beams are horizontal, and they connect two rafters that meet at the ridge. …
- Ridge Board. At the very peak of the roof, you’ll find the ridge board. …
- Top Plate. …
- Ceiling Joist. …
- Fascia Board. …
- Underpurlin. …
- Strut.
6.07.2020
What are the two main types of roof support systems?
Most Common Types of Roof Trusses
- Gable Trusses. A variety of the trusses shown above fit into the common or gable truss category, including the King Post, Queen Post, Howe, and Double Howe trusses. …
- Hip Truss. …
- Scissor Roof Truss. …
- Attic Truss. …
- Mono Truss. …
- North Light Roof Truss. …
- Flat Truss. …
- Gambrel Truss.
9.12.2019
How are roof trusses supported?
A timber roof truss is a structural framework of timbers designed to bridge the space above a room and to provide support for a roof. … A roof truss is cross-braced into a stable, rigid unit. Ideally, it balances all of the lateral forces against one another, and thrusts only directly downwards on the supporting walls.
Which is better rafters or trusses?
Once in place, rafters use up more wood, so they weigh more, but trusses are stronger because they are more efficient and have the capacity to produce maximum strength using fewer materials in the end.
What do roof rafters sit on?
The rafter tie resists the outward forces imposed on the load-bearing walls. As the rafters sit on top of the wall plates at an angle, they exert horizontal forces on the exterior walls. Rafter ties, which often double as ceiling joists, prevent these horizontal forces from causing the walls to “pancake.”
What are the four main parts of a roof?
Parts of a roof
- Decking (or sheathing) Usually made from 1⁄2-inch plywood, the decking closes and reinforces the roof structure and provides a nailbed for the shingles. …
- Roof edge (or eaves edge) All the boards running along the edge of the roof or eaves. …
- Attic. …
- Saddle. …
- Ridge. …
- Valley. …
- Underlay membrane. …
- Eaves membrane.
What is a four sided roof called?
A mansard roof is a four-sided roof with a double slope on each side forming a low-pitched roof. A mansard roof can help create extra living space. A garret is a full attic or living quarters that can be used.
What are the component of a roof?
The four components that make up a roofing system are shingles, underlayment, starter shingles and hip and ridge shingles.
What are the 3 types of trusses?
Common types of roof truss
- King Post truss. A king post truss is typically used for short spans. …
- Queen Post truss. A queen post truss is typically a vertical upright with two triangles either side. …
- Fink truss. …
- Double Pitch Profile truss. …
- Mono Pitch Truss. …
- Scissor Truss (also known as Vaulted Truss) …
- Raised Tie Truss.
What is the most common roof truss?
A fink truss is the most common type of truss used, especially on homes and pedestrian buildings. The truss has an internal web configuration shaped like a W to give the ultimate strength to material ratio for spans from around 5m to around 9m in span which covers the majority of domestic dwelling being built today.
What is the best roof truss design?
Raised chord is the most common type, providing excellent structural support and greater energy efficiency. Parallel chords are used on flat or low-slope roofs. Scissors create vaulted interior ceilings and are designed to bear additional weight of heavy snows. They are frequently used where beams are exposed inside.
Do roof trusses need support in the middle?
Generally, you don’t need central support for domestic trusses. In industrial applications, trusses support enormous roofs made from heavy materials and thus generally require central support. … When it doubt, always add additional support to prevent the risk of collapse.
Are roof trusses load bearing?
Most exterior walls are load bearing, but not all. It all comes down to where the roof trusses/rafters and floor joists/trusses are bearing.
How much weight can roof trusses support?
The live loads a truss is required to bear are determined by local building codes. If the bottom chord of a roof truss functions as a floor joist, such as in an attic room, it carries a live load that also varies by use, but a typical live floor load for a residential space is about 40 pounds per square foot.