Alternate roofing

ALTERNATE ROOFING MATERIALS

TO R.C.C

• Stone slab roofing

• Jack arch roofing

• Madras roofing

• Deck roofing

● 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

• 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.

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.

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.

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.

METHODS OF CONSTRUCTION

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

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.

JACK ARCH ROOFING

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.

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.

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.

CONSTRUCTION DETAILS

JACK ARCH AT AUROVILLE

MADRAS TERRACE ROOFING

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.

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.

Construction Process

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.

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

DECK ROOFING

DECK ROOFING

• A flat open portion top of a roof such as a terrace or a sun deck

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.

STEEL DECK ROOFING

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

WOOD DECK ROOFING

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

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 insulatedusing adhered insulation panels or cast-in-placelightweight insulating panels.

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.

Source● http://www.ruralhousingnetwork.in/technology/56adb59c336c497dc92b53d6

● https://www.google.co.in

Thank you!