Chapter 8 Roofs Flashcards Preview

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Flashcards in Chapter 8 Roofs Deck (30):
1

Dead load

The weight of the bldg itself and anything permanently attached

2

Diagonal sheathing

45 degree angle
1 X 6
After 1930

3

Jack rafter

Used in hips or valleys to span between ridge board or wall plates

4

LW truss

2 x4 or smaller
ELW

5

Live Load

Any load other than a dead load
Transient and moving
People, snow, furniture

6

Roof slope/pitch

Rise/run

7

Open sheathing or skip sheathing

1 x4 or 1x6 are spaced out
4 to6" gaps

8

Straight sheathing

90 degrees
1 X 6" boards

9

8 Roof types

Gable
Gambrel
Arch
Bridge Truss
Flat
Hip
Monitor
Sawtooth

10

Common size for gusset plates

18 gauge
3/8" bite

11

At what temps will the glue on mitered finger joints of LW trusses separate?

350 to 400 F

12

Where to look for clues on the rafter size?

Rear of building since it may not have soffits

13

Best indicator of LW truss?

2x4 exposed rafter tails

14

How much less is burn time of LW trusses?

1/4th

15

Spacing for trussed rafters

24"

16

Valley rafter

On a hip roof, where two roof lines join

17

Gambrel roof design

The lower slope is steeper than the upper slope

18

Hazards of a Gambrel roof

Storage, contents
Roof operations

19

What differentiates a Sawtooth roof construction?

Use of 2x8 rafters, with wood or metal for bracing

20

Shed roof

Flat roof with a pitch that exceeds 10 degrees

21

7 types of flat roofs

Conventional
Wooden I joist
Open web
Metal gusset or glue
Panelized
Open web bar
Nonstructural LW concrete

22

Most common flat roof?

Metal Gusset plate

23

What type of blade do you use to get through a flat non structural concrete roof?

Rotary saw with a carbide tipped wood blade or multi use blade
Or chainsaw with a carbide blade, but it will fuck it up

Note: book says multi use in summary

24

Main era for Bridge truss style roof?

Historical and Industrial

25

Identify an Arched truss/rigid truss/Rib Arch

Bottom chord sits on wall

On a bowstring, the top chord sits on the wall

26

Identify a Bowstring Truss

Top chord sits on wall
Vertical members are in compression
Diagonal members are in tension

27

Wauldbaum's center roof collapse was caused by:

Double rain roof
Concealed spaces in ceiling
Failure to recognize signs of weakening

28

How long can Timber Truss Roofs last in a fire?

30 minutes or more

29

4 factors that affect timber truss roof failure

Alterations
Mass
Location
Size

30

Metal roofs save how much energy and are made of

20%

22g-26g