1. dead load, live load
1.1. dead load of a roof refers to the weight of the roof which includes framing members and roof covering
1.2. live load of a roof includes the weight of the works and materials are supported by the roofing during construction and repairs
2. loading
2.1. concrete tiles
2.1.1. loaded in small stacks distributed across the roof
2.2. shingles
2.2.1. loaded across the ridge never loaded in valleys or eave
2.3. EPDM
2.3.1. distributed across multiple trusses or beams
2.4. insulation
2.4.1. in wet conditions cat X in package use tarp to avoid moisture always weight down
3. roofs in snowy areas are built with a steeper pitch
4. commercial buildings are built stronger then residential because they usually cover a wider span and often serve as support for machinery and other heavy equipment
5. max slope for aggregate asphalt is 3:12
6. drains should always be in the low point of the roof
7. term and definitions
7.1. hip
7.1.1. The ridge formed by the intersection of two sloping surfaces, where the exterior angle is greater than 180 degrees.
7.2. valley
7.2.1. reverse of hip 2 roof surfaces making external angle less then 180 degrees
7.3. rake edge
7.3.1. the edge of the gable running between the eaves and ridge
7.4. ridge
7.4.1. the apex line of a sloping roof
7.5. eave
7.5.1. the lower of the inclined roof surface
7.6. jack rafter
7.6.1. rafter shorter in length, which run from hip or valley to the eave
8. elements of pitch
8.1. span
8.1.1. overall width of the building
8.2. run
8.2.1. always half the span
8.3. rise
8.3.1. the vertical distance between the top of the ridge and the top of the plate line
8.4. pitch
8.4.1. the inclination of the sides of a roof the the horizontal plane
8.4.1.1. expressed in terms of degree or as a ratio of rise to span
9. types of roofs
9.1. shed
9.2. gable
9.3. hip
9.4. gambrel
9.5. mansard
9.6. flat
9.6.1. 1/4 slope per 1 foot
9.6.1.1. ponding water should evaporate within 48 hours
9.7. A-frame
9.8. butterfly
9.9. pyramid
9.10. barrel
9.11. geodesic
9.12. sawtooth
9.13. dome
9.14. conical
9.15. segmented dome
9.16. dormer
9.16.1. A projection through the main roof used to allow placement of windows on a sloped area
10. types of roof sheathing
10.1. steel deck
10.2. plywood
10.2.1. plywood should always be run across rafters
10.3. OSB
10.3.1. smooth side down if smooth side is up it can be very slippery
10.4. shiplap
10.4.1. not used anymore