11 Roofs Flashcards

1
Q

Roofs are water proof and can hinder ladder pipes. If it collapses into the structure it can

A

Cover fire preventing water from getting to it

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2
Q

Three styles of roof

A

Flat
Pitched
Curved

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3
Q

Low slope roof

A

3/12 pitch, slopes up 3 units for every 12 horizontal

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4
Q

Medium to high pitch

A

4/12 and 12/12,

12/12 is 45 degrees

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5
Q

Some bull dings have pitches greater than 18/12 which is too steep to

A

Work on from a roof ladder

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6
Q

Shed roof

A

Pitches with single sloping aspect, half gable

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7
Q

Gable roof

A

Two inclined surfaces that meet in the middle forming a ridge

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8
Q

Hip roof

A

Same as gable except the gable ends pitch in to meet the ridge line, slopes in fours directions

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9
Q

Gambrel

A

Style of gabled roof where each side slopes at two different angles, used on barns or similar.

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10
Q

Mansard

A

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

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11
Q

Butterfly

A

V shaped roofs, like two shed roofs connected at lower edge. Inverted gable looking

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12
Q

Monitor roof

A

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.

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13
Q

Clerestories

A

Vertical walls of coupola of monitor roof, normally operable windows.

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14
Q

Sawtooth roof

A

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.

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15
Q

Curved roofs

A

Form made from structural systems supporting them. Frequently arches and bowstring truss

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16
Q

Lamellas

A

Vary from 2x8”, 3x16”, and lengths from 8-14’ used to form arched roof

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17
Q

Lamella arch

A

Short lamellas bolted together diagonally using lamellas washers and curvature formed by inclining the ends. Common with gym, auditoriums, sports domes, exhibition halls.

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18
Q

Geodesic domes

A

Formed suing three dimensional triangles

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19
Q

Flat roofs are supported by

A

Joists, I beams, box beams, open web trusses. Of either wood steel, possibly concrete.

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20
Q

Inverted flat roof

A

Main joists at level of ceiling, framework constructed above them to support roof deck. Creates tall void space

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21
Q

Rafter(ed) roof, or rafters

A

Inclined joists used to support pitched roofs. Though trusses can be used

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22
Q

Trusses fail under fire load because

A

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.

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23
Q

Fink truss,

A

pitched residential type truss

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24
Q

Monoplane truss

A

All Chords and diagonal members lie on the same plane.

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25
Q

Lightweight wood truss are composed of

A

Gang nail gusset plates, individual wood members of 2x4 or 2x6, trusses spaced 2-4’ on center.

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26
Q

Bowstring truss utilizes what for top chord

A

Curved. Often laminated, top chord.

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27
Q

Fink or Pratt style truss

A

Most common for pitched roofs, made in wood or steel.

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28
Q

Tie rod failure of arch

A

It rod connects between two ends of bottom of arch, failure will result in ends of arch pushing out and failing

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29
Q

Wood panel roof decking has minimum thickness of

A

1/2”

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30
Q

Wood plank roof decking has minimal thickness of

A

1”

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31
Q

Corrugated steel for roof decking varies from what gauge and thickness

A

29-12 gauge and overall depth of 3/4-2”

A flat bar of steel can be welded on bottom for rigidity.

32
Q

Precast concrete can be made able to be nailed into for roofing materials if

A

The appropriate aggregate is used. cast in place is not nailable. Wood must be affixed or embedded in cast in place to nail roof material into

33
Q

Flat roof multistory. Uit dings typically use what type of construction for the roof

A

Same As it used for the floors

34
Q

Roof coverings provide

A

Water resistant barrier for thereof system.

35
Q

Flat roof component layers

A
Vapor barrier 
Drainage layer 
Wear course
Thermal insulation 
Roofing membrane.
36
Q

Vapor barrier

A

Watertight material used to prevent passage of moisture or vapor through what it protects. Reduce diffusion of moisture through insulation layer. Required when exterior temp averages less than 40 and interior is 45% or greater, 68

37
Q

Thermal insulation

A

Reduces heat loss through roof. Must withstand mechanical damage like gouging, moisture decay, or fire

38
Q

Membrane roof

A

Roof covering- single layer of waterproof synthetic membrane over one or mare layers of insulation and roof deck. Aka single ply roof.

39
Q

Built up membranes

A

Several overlapping layers of roofing felt glued together and saturated with bituminous material, either tar or asphalt. 4 layers common

40
Q

Single membrane roof

A

Single membrane sheets 10-20 ft wide and up to 200 ft long, typically 0.03-0.10 inch thick.

41
Q

Single ply roof membranes are made of

A

Rubber, ethylene propylene diene monomer EPDM
polyvinyl chloride PVC
chlorinated polyethylene CPE

42
Q

Single ply can be heated on bottom with torch to cause it to adhere to roof, this can commonly cause

A

Roof fires

43
Q

Fluid applied membranes.

A

Useful for curved roofs or domes, liquid applied and allowed to cure. Neoprene, silicone, polyurethane, butyl rubber

44
Q

Drainage layer may be

A

Fabric, ballast gravel

45
Q

Wear course

A

External covering of roof that protects it from mechanical wear. Tar and grave, roof uses gravel as wear course, or aggregate in built up roof.

46
Q

Pitched roof ove rings fall into two categories.

A

Shingle or tile

Metal

47
Q

Wood shingles

A

Shingles are thin tapered sawn From trees

48
Q

Shakes

A

Split wood by hand or machine and thicker than shingles.

49
Q

Shingles or shakes are made from

A

Red or white cedar, or redwood because of rot resistance.

50
Q

Asphalt shingles

A

Asphalt impregnated felt made of rag, paper, Fiberglass, or wool. Mineral aggregate on top to provide wear resistance and color, typically 12x36 sheets.

51
Q

Slate shingles are how thick

A

1/16 to 1.5 inches

52
Q

Slate roofs weight

A

8-36 lbs/ft2

53
Q

Curved clay tiles are known as

A

Mission tiles

54
Q

Concrete tiles

A

Portland cement aggregate and water.

55
Q

Shingles can be applied over what type of roofs

A

Solid deck, covered in sheathing

Or open deck, furring nailed to rafters for shingles to be nailed on.

56
Q

Roofing Wood shakes or shingles are flammable but wind resistant. To reduce flammability what is done to some types

A

Pressure treated with fire retardant, lasts well through weathering. Painting or staining reduces efficacy.

57
Q

Asphalt shingles are flammable and can drop and run. What reduces their flammability.

A

Grit surface.

58
Q

Hazards of clay, slate and tile roofs

A

Tiles can become loose or fall off
Can be slippery
Slate can be sharp

59
Q

Metal roof covering are made of

A

Galvanized iron or steel, copper, zinc, aluminum and lead.

60
Q

Corrugated steel roofing sheets may be strong enough to be used without decking underneath. They are supported by

A

Beams or purlins spacing from 2-6’

61
Q

Class a roof coverings are effective against

A

Severe fire exposure

62
Q

Class b roof coverings are effective against

A

Moderate fire exposure

63
Q

Class c roof coverings are effective against

A

Light fire exposure.

64
Q

Rain roof

A

Second roof constructed over existing. Usually over worn out roof. Like a second roof system over old one, creates voids.

65
Q

Green roof

A

Makes use of roof space for a garden.

66
Q

Green roof benefits

A

Co2 oxygen exchange for environment, added insulation.

67
Q

Roof system for green roof must support dead load of greenery which can consist of

A

A few inches up to 2’ of soil, dead loads varying from 20-150 lbs/ft2

68
Q

Green roofs can interfere with what firefighting operations

A

Ventilation or attack.

69
Q

Photovoltaic roof

A

Solar energy roof

70
Q

Risks of solar roofs

A

Electrical energy still retained in panel after pier is shut off. Do not break.
Tripping or falling hazard.
Inhalation hazard.

71
Q

Air supported roofs

A

Typically used in sports arenas for year round use. Practice facility.

72
Q

Attempts to ventilate air supported roofs wil, cause

A

Loss of interior support pressure, can’t support ff weight

73
Q

Penthouse

A

Structure built on top of roof for living space, covering of stairs or housing mechanical or utilities. So wit es,now as bulkhead.

74
Q

Some penthouses may not be accessible from inside the building and need to be accessed from

A

Roof, frequent with elevator or mechanical equipment.

75
Q

Skylights may be located over

A

Atrium, stairwell, or light shaft. Typically serves top floor though.

76
Q

Underside of roofs can have ceilings or

A

Be left exposed inside.

77
Q

Fundamental safety points regarding roofs

A

Roofs aren’t as strong as floor, designed for lighter live load
Concealed space between ceiling and roof deck, extension
Loads may be added to roofs it wasn’t designed to hold
Deteriorate from elements, may have several layers from repair.