BC 11

Question 1

fundamental safety points of roofs

Answer 1

usually not as strong as floors because they are designed to support lighter live loads

inherent concealed spaces between ceiling and roof deck, difficult to tell how much fire has developed overhead

over time loads may be added to roofs for which they weren’t designed

Question 2

pitched roofs

Answer 2

low slope- up to 3/12 means for each 12 units horizontal roof slopes upward 3 units
medium to high slope-4/12-12/12
some churches or mansions have 18/12

Question 3

gable roof

Answer 3

two inclined surfaces that meet at the ridge

Question 4

hip roof

Answer 4

slopes in four directions, degree of slope like Gable roof

Question 5

gambrel roofs

Answer 5

slope in two directions, break in the slope on each side

Question 6

mansard roof

Answer 6

break in the slope on all four sides.
modern mansard has a flat roof deck
false mansard sometimes added to front of flat roof

Question 7

butterfly roof

Answer 7

slopes in two directions
2 shed roofs thet meet at the low eave

Question 8

monitor roof

Answer 8

monitor roof extends several feet above the roof. vertical sides usually contain windows known as clerestories

Question 9

sawtooth roof

Answer 9

common in industrial for light and ventilation glass should face north

Question 10

conventional roof framing

Answer 10

use inclined members to support types of pitched roofs that are built on site using dimensional lumbar

rafters
ridge boards
collar ties
ceiling joists and rafter ties

Question 11

sizes of roof members

Answer 11

ridge beam usually one size larger than rafter
rafter- 2x4-2x14 spaced 12-24 inches apart

Question 12

common roof truss

Answer 12

all chords and diagonal members in the same plane. typical of lightweight trusses

Question 13

roof trusses

Answer 13

2x4 or 2x6 2-4 feet apart on center
should consider defensive attack

Question 14

bowstring truss

Answer 14

split ring connectors at all joints except where heel meets ends of the truss
top chord-bow
bottom chord- string

Question 15

roof deck

Answer 15

rolled materials
plywood
wood planks
correlated steel
precast gypsum or concrete planks
poured gypsum
poured concrete
cement planks containing wood fiber

Question 16

wood planks

Answer 16

wood panel decking thickness of 1.2 inch on supports 24 inches on center
wood planks min 1 inch nominal thickness

Question 17

correlated steel decking

Answer 17

29-12 gauge with depth from 3/4-2 inches

Question 18

vapor barrier of flat roof coverings

Answer 18

reduce the diffusion of interior moisture into the insulation layer

Question 19

built up roofing membrane

Answer 19

several overlapping layers of roofing felt saturated with bituminous material like tar or asphalt

Question 20

single ply membrane

Answer 20

single membrane laid in sheets 10-20 ft wide and up to 200 ft long
most commonly synthetic rubber
ethylene propylene diene monomer (EPDM)
polyvinyl chloride(PVC)
chlorinated polyethylene (CPE)

Question 21

fluid applied membranes

Answer 21

curved roofs or domes
neoprene
silicone
polyeruthane
butyl rubber

Question 22

modern asphalt shingles

Answer 22

fiberglass based with mineral aggragate embedded on surface
12x36 inches

Question 23

roof covering classification

Answer 23

class A: coverings are effective against severe fire exposure
B: are effective against moderate fire exposure
C: coverings are effective against light fire exposure

Question 24

PV systems

Answer 24

photovoltaic roof
cell
panel
array system of panels

Question 25

rooftop gardens

Answer 25

depending on depths of soil the dead load can be 20lb-150lbs per sq foot