Transcript ROOF AND ROOF COVERINGS.pptx

ROOF AND ROOF COVERINGS
INTRODUCTION
• Roof is the upper most portion of the building
which protects the building from rain, wind and
sun.
REQUIREMENTS:
a.
b.
c.
d.
e.
Structurally sound and strong
Water proof with good drainage
Protect from sun, rain and adverse weather conditions
Adequate thermal and sound insulation
Fire resistant
Types of Roofs
• Pitched or sloping roof:
Suitable for areas of heavy rain and snowfall
• Flat Roofs or Terraced Roofs
Rainfall is moderate- slight slope (not more
than 10°) is given
• Curved Roofs
For auditoriums, theatres- Shells and Domes
preferred when large column free area is required
SHELLS OR
DOMES
TERMS USED
• Span:
Distance b/w the supports
• Rise: Vertical distance b/w top of ridge to wall plate
• Pitch:
slope of the roof (rise/ span)
• Ridge :
Apex line of sloping roof
• Eaves:
Lower end of inclined roof
• Hip:
ridge formed by intersection of two sloping surface.
Ext angle >180
• Valley : reverse of Hip
• Principle rafter : member running
from ridge to eaves
• Purlins : Members running horizontal
to support roofing material
• Truss: framework, usually of well conditioned
triangles, designed to support roof coverings
or ceilings over rooms
STEEL ROOF TRUSSES
 Fabricated from rolled steel
structural members
 Channels, angles, T and plate
sections
Mostly angles used - can resist
both tension and compression
Advantages:
 Economical, Easy to fabricate
Fire proof, Rigid
Permanent, Suitable for speedy
construction
Connections in a roof truss
ROOF COVERINGS
CORRUGATED
SEMI CORRUGATED
PLAIN
COMMONLY USED:
I. ASBESTOS- CEMENT SHEETS
II. ALUMINIUM SHEETS
III.GALVANIZED IRON SHEETS
IV.FIBRE SHEETS
V. TILES
I. ASBESTOS- CEMENT SHEETS
Cement & asbestos
Purlin spacing: 1 to 1.5 m
Advantages:
Cheap, tough, durable, water tight,
fire resistant, light weight, do not
rust
Disadvantages :
Low thermal conductivity, not
attractive
II. ALUMINIUM SHEETS
Aluminium + Mg (strength)
Lightest roof covering
Advantage: Reflects heat,
corrosion free
Application: Warehouses
Industrial bldg
Automobile sheds
III. GALVANIZED IRON SHEETS
Iron sheets- galvanized with zinc
Advantages: durable, light, fire
proof
Disadvantages: Condensation
problem in the inner side, transmit
heat and cold easily
Application: Factories, workshop
sheds, cost effective bldg
IV. FIBRE SHEETS
• Advantages: light
weight, rust proof, can
be cut easily
• Eg: PVC sheets
Poly carbonic sheets
V. TILES
• Oldest roof covering
• Allahabad tile,
Mangalore tile etc.
• Manufactured with clay
• Advantages: non
conductors of heat and
cold, prevents extreme
changes in temperature
within bldg
Thank you