Roof framing Flashcards
What are ceiling joists?
Ceiling joists are those horizontal members that create the ceiling.
What has these three functions:
- Carry finished ceiling load (drywall)
- Act as a second story floor
- Resists outward thrust of rafters
Ceiling joists
Overlap nailing of rafter and ceiling joist. True or false?
True
Ceiling Joists and/or Rafters may need additional hardware .Long TimberLok screws fasten through _____ into the ____ or _____
Long TimberLok screws fasten through both plates into the rafter or truss
The lack of ceiling joists and other framing such as a structural ridge beam may cause structural deformities to occur over time. True or false?
True
Structural ridging resists what?
Sagging
The Ceiling can be reinforced by what two things?
- Strong Back
2. Backing/blocking
What is strong back and what is backing/blocking?
Strongback - 2x’s nailed to top of the ceiling joists at mid-span, provides stiffness. Used only on long spans.
Backing/Blocking – attachment point for partitions running parallel to ceiling joists, also acts as a nailer for drywall.
What are some common rafter parts/ terms. describe each
Span - building width
Run - one half span; horizontal distance under rafter.
Rise – vertical roof height.
Line Length - rafter length, length of rafter minus tail
Ridge – Framing member the tip of the rafter is fastened to
How to find the unit length? How to find Total unit rise ?
Unit Length = found using Pythagorean Theorem
Square root of (Unit Rise2 + Unit Run2)
Total Rise = in terms of inches.
Found by formula Run x Unit Rise
How is overhang measured? How is projection measured?
Overhang is measured along slope of the tail.
Projection is the run of the tail, measured perpendicular to the house wall.
Seat cut is also known as the bird’s mouth. True or false?
True
Plumb cuts are vertical when installed.
Level cuts are level. True or false?
True
What is the common term for roof steepness,
stated as Unit Rise on Unit Run(
Example if Unit Rise is 10 inches then ______ is stated “10 on 12”.)
The slope
Slope # (unit rise) is always compared to 12. The larger the number, the steeper the slope! True or False?
True
What is a ridge board and why is it often dropped .
Ridge board – member to which the upper ends of the rafters are attached.
Often dropped to allow for better support/ventilation.
Where are end rafters located and what supports rake rafters?
Rake rafter should be supported by lookouts
End rafter, typically is outside the building line.
What are collar ties used for? Should they be 1/4 of the span or greater, about 6’ OC?
Collar Ties
Used to reinforce the rafters near the mid span.
Should be 1/3 of the span or greater, about 4’ OC.
What are gable end studs?
Gable End Studs
Non load bearing studs that enclose the triangular gable end of a building.
When framed properly, they have a common difference in length (CD).
What is a hip roof?
A hip roof is a system where hip and common rafters meet at the ridge
Hip rafter size should be one size larger than the common rafter. True or False?
True
The run of a hip rafter is usually at a ____angle with the ____ ______.
The run of a hip rafter is usually at a 45 angle with the wall plates.