Floor, Wall & Roof Framing Flashcards

What is the purpose of hurricane ties (rafter ties) connecting rafters to wall plates?

Answer: To resist uplift forces from wind that try to lift the roof off the wall

Hurricane ties (also called rafter ties or H-straps) are metal connectors that anchor rafters directly to the wall framing. They resist uplift forces from wind pressure acting on the underside of roof overhangs and from negative pressure on the roof surface.

A carpenter needs to install a flush beam in a floor system so its bottom is level with the joist bottoms. How are the joists connected to the flush beam?

Answer: With joist hangers (metal hanger connectors) nailed to the beam face

When a beam is flush (same depth) with the joists, the joists cannot sit on top of the beam. Metal joist hangers are face-nailed to the beam and support the joist ends from below, keeping all bottom surfaces level.

What is a gable end wall and how is it framed differently from a standard stud wall?

Answer: The triangular end wall of a gable roof — framed with studs of varying heights cut to follow the roof slope

Gable end walls are the triangular walls at each end of a gable roof. Studs rise from the top plate at standard spacing but are cut at an angle at the top to follow the slope of the roof. There is no king stud at the apex — only a ridge board connection.

What is the difference between a plumb cut and a seat cut on a common rafter?

Answer: A plumb cut is vertical (parallel to a plumb line); a seat cut is horizontal (level)

At the birdsmouth, two cuts are made: the plumb cut is vertical (perpendicular to the slope, parallel to a plumb bob line) forming the vertical face of the notch, while the seat cut is horizontal (level) forming the flat bearing surface that sits on the top plate.

When installing cross bridging between floor joists, at what stage of construction should the bridging be nailed at the bottom?

Answer: After the subfloor is installed and the floor is loaded

Cross bridging is installed with the tops nailed before the subfloor goes down. The bottoms are left loose until after the subfloor is installed and loading occurs, which straightens the joists. Nailing bottoms early prevents the joists from aligning properly under load.

What is the function of collar ties in a roof frame?

Answer: To resist outward thrust at the ridge by connecting opposing rafters in the upper third of the roof

Collar ties (or collar beams) are horizontal members connecting opposing common rafters in the upper third of the attic. They resist the tendency of rafters to spread outward under load. Per the NBC, they must be in the upper third of the attic space.