ROOF COVERING

CONTENTS

INTRODUCTION

PROPERTIES

FACTORS AFFECTING THE SELECTION OF

ROOFING MATERIAL

TYPES OF ROOF COVERING

ROOFING TILES: INTRODUCTION

Roofing tiles are used to cover sloping roofs.

Supported on wooden reapers or light gauge

steel or steed rods are also used.

Normally these tiles are having curved surface

having ribbed sections, so that with thin

section they are sufficiently strong to resist

the load.

Some times flat tiles are used under

curved/ribbed tiles.

THE DESIRABLE PROPERTIES OF THE ROOFING TILES ARE:

1. They should not absorb moisture more than 20 per cent by weight.

2. They should give pleasing look.3. They should be capable of taking load

of a man safely, after they are supported on reapers.

4. They should be durable.5. They should be uniform in shape and

size.6. warpage should not exceed 2% along

the edges and 1.5% along the diagonal.

FACTORS AFFECTING THE SELECTION OF ROOFING MATERIAL

• Type of building• Type of framework• Initial cost• Maintenance requirements• Fabrication facilities• Appearance and special features of locality • Availability of material• Climate of locality

TYPES OF ROOF COVERING

• SLATE ROOFING TILES

• ALLHABAD TILES

• BURNT CLAY TILES

• CONCRETE TILES

SLATES ROOFING

• Extremely low water absorption index, less than 0.4%, which makes its resistant to frost damage.

• Consists of bituminous slates called eternit (generic term for fiber cement).

• Available in three colours-grey,black and red.

• SIZE- 12’’x6’’, 6mm thickness

• COST- 25-30/Sq.ft

Each slab is divided into thin laminate or slate by using splitters

Reduced to slabs after dividing into sections using diamond or circular

saw.

Slates are obtained from quarries as blocks

04/09/2023

FIXING

Slates roofs tiles are usually fixed either with nails or with hooks.

Fixing is typically with double nails onto timber battens or nailed direclty onto timbersarking boards.

nails are made up of alloy and stainless steel.

LAYING

• Laid such that each slate overlaps a slate in the next course below it.

• Two holes are made from the bed of the slab at the centre or head so

• Slates are fixed to battens by copper or zinc nails.

• The spacing of battens i.e,gauge is determined as

gauge=(length of slate-lap)/2

• A layer of felt is used below slate to exclude rain water and moisture.

BattensSLATES OVERLAP

ALLAHABADTILES

• Allahabad tiles are generally laid side by side and the joints are covered with half round tiles.

• It consists of flat broad bottom undertile that alternate with convex curved overtile.

• Unfertile is flat,tapered,with flanges at the side.

• The overtile is half round and tapered in plan with diameter tapering from 16 cm at tail to 12 cm at the head.

• The taper in the overtile allow the tile in next course to fit in.

• Vertical battens of size 2.2cmx7.5cm are fixed between sides of adjacent undertiles and to these half round overtiles.

• Overtiles are fixed to vertical battens with 75 mm nails.• Cost- 55-145 Sq.ft

BURNT CLAY TILES

Clay roofing tile is a good choice for homes with a southwestern, Italian, or Spanish Mission design, or even for homes with a modern, clean look. 

Tile lasts a long time

Burnt clay tile roofs are only used for sloping roofs between about 20° and 50° inclination of rafter.

Clay tiles are heavy, requiring a strong substructure and closely spaced battens.

SIZES- 2’’x6’’

            3’’x 8’’(Max) COST-45-65/ sq.ft 

ADVANTAGE Tile won't rot or burn, and it

can't be harmed by insects.

The color of a clay tile is not affected by exposure to the elements, it can easily last for 100of years.

DISADVANTAGE A major problem of clay tiles is the

immense loss due to cracking and breakage.

Clay tile production is a traditional village craft in many regions, but uniform shapes and qualities are difficult to achieve.

Special properties- Durable, waterproof

cladding for sloped roofs

Economical aspects -Low to medium costs

Resistance to earthquake- Low

Resistance to hurricane- Medium to good

Resistance to rain- Very good

Resistance to insects -Very good

Climatic suitability- All climates, but most

common in humid areas

PROCESS USED TO CREATE OBJECTS OF A FIXED, CROSS-SECTIONAL PROFILE

MAINTENANCE Burnt clay tiles requires

inspections at least twice a year so as to last for further years.

They often develop cracks with years.

A cracked tile needs to be replaced or repaired in place.

Mix up a small amount of mortar and carefully fill in the crack. Be sure to wet the tile with plenty of water to help the mortar set up properly.

Tiles will be slippery when wet

CONCRETE TILES

Plain tiles, pantiles, Roman

tiles, interlocking tiles, and

ridge, hip and valley tiles are

made of this material.

The mixture is composed of

normal Portland cement and

clean well-graded sand.

The body treated with

mineral granules which have

been coated with color.

pantiles

ridge

Roman tiles

Durability estimates range from 30 to

50 years.

Weigh between 9 1/2 and 12 pounds(1

pound =.45 gram) per square foot.

Size is 265mm by 165 mm and 12mm

thick.

Require low maintenance

Offer good fire protection and are

resistant to rot and insects.

COST- INR 150 to INR 300/ Sq.ft

FIXING

The usual lap for plain tiling is 65mm, for pitched roof at 37 degree.

For pitches up to 60 degree the tiles should be twice nailed in every third course to once nailed in each course.

For pitches exceeding 60 degree all tiles should be nailed twice.

The nails are usually 38 mm long and may be either galvanized wrought iron, zinc, copper or composition.

MANUFACTURING

PROCESS USED TO CREATE OBJECTS OF A FIXED, CROSS-SECTIONAL PROFILE

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