Rafter: One of a series of diagonal members of the truss that meet at the apex in order to support the roof deck and its loads. Underpurlin: Horizontal beams supported by posts and used to support the mid-span of rafters to cover longer spans.
What is the top member of a truss called?
A planar truss is one where all members and nodes lie within a two-dimensional plane, while a space truss has members and nodes that extend into three dimensions. The top beams in a truss are called top chords and are typically in compression, the bottom beams are called bottom chords, and are typically in tension.
What are the members of a roof truss?
The top members of a truss are known generically as the top chord, bottom members as the bottom chord, and the interior members as webs. In historic carpentry the top chords are often called rafters, and the bottom chord is often referred to as a tie beam.
What is the member of a roof truss that serves as a ceiling joist?
The lower chord also serves as a ceiling joist. The horizontal distance of rafters from the outer edge of the wall plate to the center of the ridge. Truss used for buildings having a sloping ceiling. In general, the slope of the bottom chord is 1/2 of the slope of the top chord.
How do you support roof trusses?
Extra support for the trusses can be made by placing a 2-by-4-inch piece of lumber from each truss on one side to the truss on the other side, high enough to provide head room but low enough to provide support for the trusses. In this situation, the walls of a finished attic space or room would go with the roof line.
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 does a 6 12 pitch mean?
One of the most commonly used terms in roofing. … Roof pitch (or slope) tells you how many inches the roof rises for every 12 inches in depth. An Example of a roof pitch would be a “6/12 pitch” which means that the roof rises 6 ” for every 12″ inward towards the peak (or ridge).
What is the roof truss that has the fewest members?
The king post truss is used for simple roof trusses and short-span bridges. It is the simplest form of truss in that it is constructed of the fewest truss members (individual lengths of wood or metal).
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 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 is the top beam of a roof called?
Top Chord. The top-most beams of a roof truss. In most common roof styles, these are the two slanted beams that hang over the side of a building.
What is a roof frame called?
There are two common ways of framing the roof of a house: with premanufactured trusses, or with rafters and ceiling joists, commonly called stick framing.
What is the main beam in a roof called?
Getting a little more technical, the National Roofing Contractors Association defines the ridge as the “highest point on a roof, represented by a horizontal line where two roof areas intersect, running the length of the area.” So the ridge is basically the peak of a roof, but ridge also refers to the board or beam that …
What is the strongest roof truss design?
There is no “strongest” truss, but rather, one that is most appropriate for a specific application. There are four basic types of truss design: dropped chord, raised chord, parallel chord and scissors.
What gives a truss its strength?
Truss bridges are characterised by their interconnecting triangular structures, which give them the strength to withstand more heavy and dynamic loads than the bridges of old.