Types of the roof for building and its elements

1. Types of Roofs
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2. A roof must have the following qualities:
• A roof must be weather resistant to rain, snow, wind and sun.
• The durability of a roof should be equal to or in excess of those materials used in the
remainder of the building.
• A roof should have good thermal insulation properties.
• A roof should require a minimum of maintenance.
• A roof should be constructed in such a way as to retain structural stability when dead
and imposed loads are applied to it ( dead loads is the weight of materials used to make
the roof, imposed loads are loads created by wind, snow, etc.

3. Roof Elements
When designing a roof the following points should be considered in relation to its final
appearance.
Pitch
The steeper the pitch the greater the roof area visible. This will result in a larger roof space,
you can also use smaller cladding units such as plain tiles and slates. Pitched roofs are the
most suitable in countries where there is a high rain fall.
Coverings
Materials used for roof coverings should harmonise with the local surroundings. These
materials
should be fit for purpose in their
ability to keep out the elements,
thermal insulation, durability and
appearance.
Verge
Ridge Valley
Rafter Hipped
End
Jack
RaftersCommon
Rafters
Gable
End Lean-to
Roof
Flat Roof
Hip
Eaves

4. Roof parts
Ridge Dormer window Barge board
Eaves detail Door
Down pipe
Gutter
chimney

5. Wall plate
Usually 100 x 50 mm softwood timbers are fixed to the
of load bearing walls to distribute loads and provide
fixings for roof timbers.
Ceiling joist
These are timbers which provide a support for fixing
ceiling
finishes and act as a collar to prevent rafters spreading.
Common rafters
These are inclined timbers fixed between wall plate and
ridge which transmit live and dead loads to wall
Ridge
The ridge is a horizontal board set on edge to which the
rafters are attached (not required on trussed rafters).
Hip Rafter
A hip rafter is a rafter running from the wall plate to the
ridge
which forms the external angle of the sloping side of a roof.
Purlin
This is a horizontal roof member supporting the rafters and
usually at right angles to these. This enables small section
timbers to be used for the rafters.
Hangers
These are timbers hanging from the purlins to the ceiling
joist
to give additional support to binders.
Soffit
A horizontal board fixed to the
underside of the rafter outside
the building.
Bargeboard
Verge or gable board.
Eaves
The lower part of the roof, which usually
includes the end of
the rafter, ceiling joist, soffit, fascia and
gutter.
Dormer
A vertical window coming through a
sloping roof.
Valley
This is the name for the intersection
between two sloping surfaces,
forming an internal angle ( the opposite
to a hip).
Fascia
A board fixed vertically to rafter ends,
which provide an additional fixing
for gutters.

6. Pitched roof
Roof with a gable end
If the roof space is or may
be intended to be used in
the future, the structure
should be designed
accordingly.

7. PITCHED ROOF: TIMBER - truss
STEEL - truss
Truss built as from
individual members
Truss fabricated from factory
Truss fabricated from factory
Whole roof structure built from
steel
Gang nails
steel

8. Pitched roof with
dormer windows
A pitched roof with dormer
windows.
Timber to support the dormer
window
Common
Rafter
Lay
boardWhen a steep pitched roof is used in
domestic construction dormer windows
can be used to create additional head
room in the roof space. This allows the
roof space to be utilised for habitable
rooms.

9. A pitched roof
column
wall
columns
walls
A mono-pitched roof structure
A lean-to roof structure

10. Eaves detail pitched roof

11. Flat roof
• Slope – 0-10⁰
• Structural decks ordinary used
– Wood panels over wood joist
– Solid wood decking over heavy timber framing
– Corrugated steel decking
– Sitecast concrete slab
– Precast concrete slab
– Panels of wood fibre bonded together with portland
cement etc
Water pool formed due to
poor workmanship

12. Gable Roof

14. Hip Roof

17. Gambrel Roof

19. Mansard Roof

21. Shed Roof

22. Flat Roof

29. PARASOL ROOFING
FREE FORM ROOFING
HYPERBOLIC PARABOLOID ROOFING
HYPERBOLIC PARABOLOID ROOFING

30. 3. Space frame
A space frame or space structure is a truss-like,
lightweight rigid structure constructed from
interlocking struts in a geometric pattern. Space
frames usually utilize a multidirectional span, and are
often used to accomplish long spans with few
supports. They derive their strength from the
inherent rigidity of the triangular frame; flexing loads
(bending moments) are transmitted as tension and
compression loads along the length of each strut.

31. Dome

32. Dome

33. 4. ROOF SHELL

35. 5. FOLDED PLATE ROOF

36. 6. MEMBRANE

37. 6. MEMBRANE