Flashcards in 11 Roofs Deck (77)
Roofs are water proof and can hinder ladder pipes. If it collapses into the structure it can
Cover fire preventing water from getting to it
Three styles of roof
Low slope roof
3/12 pitch, slopes up 3 units for every 12 horizontal
Medium to high pitch
4/12 and 12/12,
12/12 is 45 degrees
Some bull dings have pitches greater than 18/12 which is too steep to
Work on from a roof ladder
Pitches with single sloping aspect, half gable
Two inclined surfaces that meet in the middle forming a ridge
Same as gable except the gable ends pitch in to meet the ridge line, slopes in fours directions
Style of gabled roof where each side slopes at two different angles, used on barns or similar.
Similar to gambrel and hip. Slopes of two different angles, all sides slope down outside wall. Can have flat roof, modern mansard. Projects beyond wall creating void. Paris style roofs
V shaped roofs, like two shed roofs connected at lower edge. Inverted gable looking
Similar to exaggerated lantern, raised section along ridge line providing natural light and ventilation. Large coupola in middle of ridge line. Once common on factories.
Vertical walls of coupola of monitor roof, normally operable windows.
Common industrial. Used for light and ventilation. Alternating vertical walls with windows and sloping roofs. Windows should face north. Mostly eliminated from modern lighting systems.
Form made from structural systems supporting them. Frequently arches and bowstring truss
Vary from 2x8", 3x16", and lengths from 8-14' used to form arched roof
Short lamellas bolted together diagonally using lamellas washers and curvature formed by inclining the ends. Common with gym, auditoriums, sports domes, exhibition halls.
Formed suing three dimensional triangles
Flat roofs are supported by
Joists, I beams, box beams, open web trusses. Of either wood steel, possibly concrete.
Inverted flat roof
Main joists at level of ceiling, framework constructed above them to support roof deck. Creates tall void space
Rafter(ed) roof, or rafters
Inclined joists used to support pitched roofs. Though trusses can be used
Trusses fail under fire load because
Of the reduced mass of their components and interdependence on them to support themselves. Open design allows 360 fire exposure. Plus void space for extension.
pitched residential type truss
All Chords and diagonal members lie on the same plane.
Lightweight wood truss are composed of
Gang nail gusset plates, individual wood members of 2x4 or 2x6, trusses spaced 2-4' on center.
Bowstring truss utilizes what for top chord
Curved. Often laminated, top chord.
Fink or Pratt style truss
Most common for pitched roofs, made in wood or steel.
Tie rod failure of arch
It rod connects between two ends of bottom of arch, failure will result in ends of arch pushing out and failing
Wood panel roof decking has minimum thickness of