krishnakanth

1. ALTERNATE ROOFING MATERIALS
TO R.C.C

2. • Stone slab roofing
• Jack arch roofing
• Madras roofing
• Deck roofing

3. ● Alternate building materials are those which can
be used economically by replacing the
conventional building materials.
● These materials are historically appropriate,cost
effective,easy to install,and functional in wildland
fire environments.
● Eventually in stone slab roofing different forms of
mortar were used to hold the stones together,
cement being the most commonplace now.
INTRODUCTION
STONE SLAB ROOFING

4. • Where particular geology
made it easy to split stones
into large slabs or where such
flat stones were produced by
nature, they formed a natural
building material.
• Traditionally, stone slabs
provided excellent insulation
and unique looks. Stone slab
roofs are also solid and
virtually stormproof.
• Nowadays, a stone slab roof
might be seen as part of the
restoration of a heritage
building, or as a decorative
feature - although rarely as the
main roof.

5. Stone roofs
• Stone roofs are not much
used at the present time,
except for covering small
vestibules, porches,
turrets, towers, and
monumental buildings.
• They may be flat or
pitched. Large slabs are
used for flat roofs, and
small ones for pitched
roofs.

6. Methods of Construction: CONTEMPORARY METHOD
• It is a flat roofing system with
stone slabs resting over steel
or slender rcc section beams.
• The slabs are laid over the
terracing for insulation and to
provide a slope for rain water
drainage.

7. METHODS OF CONSTRUCTION :
TRADITIONAL METHOD
• In this system stone
slabs are placed over
wooden planks which
are supported on
wooden beams.
• This keeps the building
cool and is mainly
suitable for hot and dry
climate.
• There is no need of
centering and
shuttering.

8. METHODS OF CONSTRUCTION

9. TYPES OF STONE SLAB ROOFING
Ex at Karnak,Egypt
A structure with stone
walls, supporting flat
roof made of stone
slabs of large
boulders.
Corbelled
roof
Flat roof
Gabled
roof

10. Advantages and Disadvantages
• Good insulation
• Beautiful appearance
• They are solid and also storm proof
• Water proof roofing
• Durability
• Very heavy
• Labour incentive
• An obsolete cladding material
• Not suitable to withstand loading from
furniture, etc of modern residential buildings.

11. JACK ARCH ROOFING

12. INTRODUCTION
• A jack arch is classically defined as a structural element in masonry
construction that provides support at openings in the masonry.
• Alternate names are FLAT ARCH and STRAIGHT ARCH.
• Unlike regular arches, jack arches are not semicircular in form.
• Instead they are flat in profile and are used under same circumstances as
lintels.

13. MATERIALS
• This type of roof may be built with materials such as
brick, steel, concrete, and clay-gypsum mortar.
• The roofing technique in auroville is that of jack arch
roof with terra cotta hollow blocks and pre cast
concrete beams.

14. ADVANTAGES
• It can be constructed from relatively small pieces of
material that can be handled by individuals .
• Arches are typically sawn from an appropriately sized
fired clay lintel.
• There is considerable scope for in corporation of
decorative patterns and elements into jack arches.

15. CONSTRUCTION DETAILS

17. JACK ARCH AT AUROVILLE

19. MADRAS TERRACE ROOFING

20. INTRODUCTION
o This is the traditional roofing found in south
India.
o It involves the use of wood,“aachikal”(a
locally available material which is a small
brick)and lime plaster.
o These are commonly used for small spans.
o Wooden beams are used to cover the span,
over this wooden beams are laid at intervals
of less than 45 cms from each other.
o The gaps between is filled with bricks on
edge with lime plaster. Upon this “ aachikal
brick “is laid on edge across in diagonal
fashion plastered with lime.

21. CONSTRUCTION DETAILS
• STEPS IN CONSTRUCTION
o Teak wood joist are placed on rolled
steel joists.
o Sufficient slope is provided.
o Terrace bricks of size 15x75x25mm to
be laid diagonally.
o Brick bat concrete of thickness 75mm
to be laid.
o Rammed and allow to set for 3 days.
o Flat tiles are then laid over this
concrete.
o Surface of this roof is finished with 3
coats of plaster.

22. Construction Process

23. ADVANTAGES
• It is easy for construction and maintenance.
• Flat roofs possess good insulation properties.
• It provides better light,ventilation and architectural
appearance to the building.
• Upper floor can be easily constructed.
• Fire resistant.

24. DISADVANTAGES
• Madras roofs are not suitable for long span ,with out the
introduction of columns and beams.
• Initial cost is less than a pitched roof
• Not suitable for places of heavy snowfall.
• Construction speed is slower than pitched roof

25. DECK ROOFING

26. DECK ROOFING
• A flat open portion top of a roof such as a
terrace or a sun deck

27. TYPES OF DECK ROOFING
• Depending upon materials used there are four
types of deck roofing.
1.Steel deck roofing.
2.Wood deck roofing.
3.Concrete deck roofing.
4.Cement deck roofing.

28. STEEL DECK ROOFING
• Materials used in
steel deck roofs are
light- gauge , cold-
rolled sections ,
welded or screwed to
bar joists.

29. WOOD DECK ROOFING
• Materials used are
sawed lumber, asphalt ,
ply wood or OSB
(oriented strand board).

30. CONCRETE DECK ROOFING
• There are four types of concrete deck roofs
1.Structural concrete deck.
2.Structural composite concrete deck.
3.Precast concrete deck.
4.Lightweight insulating concrete deck.
• Concrete roof decks are commonly topside insulated
using adhered insulation panels or cast-in-place
lightweight insulating panels.

31. USES
• The primary use of steel roof is to support
vertical loads and the weather resisting
system , such as insulation , roofing and
waterproofing materials.
• Deck roofing can be used in garden
landscaping , to extend living areas of houses.

32. Source
● http://www.ruralhousingnetwork.in/technology/56adb59c336c497dc92b53d6
● https://www.google.co.in

33. Thank you!