0. Building Construction Related to the Fire Service
Chapter 11 — Roofs

1. Building Construction

2. Building Construction
Learning Objective 1
Identify the ways roofs can affect structural fire fighting.
Building Construction

3. Building Construction
Role in Fire Fighting
Work on top of roofs
Use as vantage point for attacking fire involving neighboring structure
Work beneath whenever inside a building
Building Construction

4. Building Construction
Safety Points
Roofs usually not as strong as floors
Inherent concealed spaces between ceiling and roof deck
Loads added over time that roofs were not designed to bear
Subject to wear and deterioration
Building Construction

5. Building Construction
Waterproof Quality
Limits penetration of streams from ladder pipes and platform apparatus
Forms waterproof covering over buried fire if collapses into a structure
Building Construction

6. Building Construction
Learning Objective 2
Describe the characteristics of the different architectural styles of roofs.
Building Construction

7. Building Construction
Flat Roofs
If completely horizontal, present drainage problems
Many have slight slope
May be sloped toward drains in center of roof
Easiest to work on, but potential danger in dark
Building Construction

8. Building Construction
Pitched Roofs
Have inclined surfaces
Low slope
Medium to high slope
Designed to shed water and snow
Hazards to firefighters
Courtesy of Chris E. Mickal, NOFD Photo Unit
Building Construction

9. Styles of Pitched Roofs
Building Construction

10. Building Construction
Curved Roofs
Most frequently supported by arches and bowstring trusses
Dome
Geodesic domes
Dormer
Building Construction

11. Building Construction
Learning Objective 3
Describe the systems used to support roofs.
Building Construction

12. Building Construction
Flat Roof Support
Wood joists supported at either end by load-bearing wall
Solid wood joists lose strength gradually as they burn
Signs of structural failure
Thin plywood or OSB can fail quickly without warning
(Continued)
Building Construction

13. Building Construction
Flat Roof Support
View any indication of heavy fire development as warning sign of structural failure
Box or I-beams of plywood and wood truss joists often used to support flat roofs
(Continued)
Building Construction

14. Building Construction
Flat Roof Support
Susceptibility to early failure
Vibration and deflection of roof
Inverted roof
Courtesy of McKinney (TX) Fire Department
Building Construction

15. Building Construction
Raftered Roof
Rafter
Inclined joist that supports pitched roof
Runs parallel to slope
Results in outward thrust against walls
Commonly made of wood
Courtesy of Wil Dane
Building Construction

16. Building Construction
Trusses
Have reduced mass and interdependence of components
Early failure in fire
Ceilings suspended from roof truss create concealed spaces
Courtesy of Dave Coombs
Building Construction

17. Building Construction
Arches
Behavior of roof supported by arch basically determined by material from which arch is constructed
May use steel tie rod between two ends of arc to resist outward thrust of arch
Building Construction

18. Building Construction
Learning Objective 4
Explain the functions of the roof deck and describe the materials used to construct it.
Building Construction

19. Building Construction
Function of Roof Decks
Portion to which roof covering is applied
Transmits loads of roof to supporting members
Concrete deck serves as roof support
Deck must not deflect excessively under anticipated loads
Building Construction

20. Building Construction
Materials
Plywood
Wood panel
Wood planks
Corrugated steel
Concrete
Cement planks
Courtesy of McKinney (TX) Fire Department
Courtesy of McKinney (TX) Fire Department
Building Construction

21. Building Construction
Learning Objective 5
Describe the types and materials used as roof coverings for the different types of roofs.
Building Construction

22. Function of Roof Coverings
Water-resistant barrier for roof system
Factors affecting choice
Form and slope of roof
Local climate
Appearance desired
Maintenance requirements
Durability
Required wind and fire resistance
Building Construction

23. Building Construction
Flat Roof Coverings
Building Construction

24. Pitched Roof Coverings
Function differently than flat roof coverings
Must be secured to roof deck or support to counter force of gravity
(Continued)
Building Construction

25. Pitched Roof Coverings
Shingles and tiles
Wood shingles and shakes
Asphalt shingles
Slate
Clay tile
Concrete tiles
Courtesy of McKinney (TX) Fire Department
(Continued)
Building Construction

26. Pitched Roof Coverings
Application of shingles and tiles
Usually attached with corrosion-resistant nails
Wood shingles
Asphalt shingles
Slate tiles
Fire performance of various shingles and tiles
Building Construction

27. Building Construction
Metal Roof Coverings
Materials include galvanized iron or steel, copper, zinc, aluminum, and lead
Can use flat or corrugated metal
Corrugated sheets generally strong enough to install without decking
Layer or roofing felt placed on deck beneath metal sheets
(Continued)
Building Construction

28. Building Construction
Metal Roof Coverings
Roofing felt increases fire resistance of wood decking
Metal roofs installed over existing wood roofs create void space
Building Construction

29. Building Construction
Metal Roof Coverings
Courtesy of Ed Prendergast
Courtesy of McKinney (TX) Fire Department
Building Construction

30. Building Construction
Learning Objective 7
Describe the characteristics of roofs installed for specific purposes.
Building Construction

31. Building Construction
Rain Roofs
A second roof constructed over older roof that is so deteriorated that it cannot be repaired
Void created between rain roof and original roof
Impedes rapid and effective ventilation
(Continued)
Building Construction

32. Building Construction
Rain Roofs
Building Construction

33. Building Construction
Green Roofs
Designed to protect environment and conserve energy
Benefits
Can vary in use
Constitutes a dead load
Fire conditions
Courtesy of Ed Prendergast
Building Construction

34. Photovoltaic (PV) Roofs
Produce clean and reliable energy used in a wide range of applications
Panels on top of or embedded in roof
Hazards to fire fighting
Electrical shock
Inhalation exposure
Falls from roof
Roof collapse
Building Construction

35. Building Construction
Learning Objective 8
Discuss the purpose of penthouses and skylights and their impact on fire fighting tactics.
Building Construction

36. Building Construction
Penthouses
Structures on main roof of building
Used for:
Stairway enclosure
Elevator machinery enclosure
Mechanical equipment storage
Additional living space
Building Construction

37. Building Construction
Skylights
Natural lighting to building interior
Serve top story or located over top of an atrium, stairwell, or light shaft
Sometimes have operable glass planes; codes require wired or tempered glass
Rapid ventilating of heat and smoke; do not provide for automatic venting
(Continued)
Building Construction

38. Building Construction
Skylights
Courtesy of McKinney (TX) Fire Department
Courtesy of McKinney (TX) Fire Department
Building Construction

39. Building Construction
Learning Objective 9
Describe the impact ceilings have on fire spread to roofs.
Building Construction

40. Building Construction
Function of Ceilings
Diffuse light and distribute air in a room
Conceal air conditioning ducts, electrical wiring, and sprinkler piping
Courtesy of McKinney (TX) Fire Department
Building Construction

41. Installation of Ceilings
Attached directly to underside of roof joists or trusses
Distance beneath roof supports creates considerable concealed space
New ceiling installed beneath existing ceiling in older buildings
Building Construction

42. Impact on Fire Fighting
Concealed space created in fire-resistive building may conceal type of roof structure above
Extent of fire development in roof spaces is hidden by ceiling
Building Construction

43. Building Construction
Know your Roofs!
Building Construction