These are also clay products like brick but are thin. Depending upon their use, building tiles may be further classified as
1. Roofing tiles
2. Flooring tiles and wall tiles.
1. Roofing Tiles: Roofing tiles are used to cover sloping roofs. They are supported on wooden reapers. Sometimes light gauge steel or steed rods are also used as reapers. After supporting on reapers these tiles should be strong enough to take load of a man safely. The tiles should he leak proof. Normally these tiles are having curved surface having ribbed sections, so that with thin section they are sufficiently
strong to resist the load. However many times flat tiles are used under curved/ribbed tiles. These tiles are not subjected to load directly. They serve in reducing adverse thermal effects. Mangalore, Allahabad tiles, and corrugated tiles are popularly used roofing tiles [Ref. Fig. 5.2]. Allahabad tiles are generally laid side by side and the joints are covered with half round tiles.
Mangalore tiles are red in colour and they are of interlocking type. These tiles are manufactured in Mangalore, Calicut, Cochin and Gujarat. Corrugated tiles satisfy the requirements of appearance and leak proof but they can be easily blown away by wind.
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.
2. Flooring Tiles and Wall Tiles: These tiles are manufactured by burning pressed green tiles twice. First they are burnt at 700°C. Then they are dipped in the glaze solution and again burnt at 1250°C to fuse them with glaze. The thickness of these tiles vary from 15 to 20 mm. These tiles are flat and they have pleasing appearance. There are two types of flooring tiles:
(a) Glazed Tiles: These tiles are used as finish surfaces for floors and walls in kitchen and bathrooms.
These tiles are glazed and are provided with attractive colours and designs.
(b) Mosaic Tiles: These are precast concrete tiles with marble chips on the top surface. After fixing these tiles polishing is done.
The desirable properties of flooring and roofing tiles are:
1. Tolerance for length = ± 5 mm.
2. Tolerance for thickness = ± 2 mm.
3. Should be uniform in shape and colour.
4. They should be sound, hard and durable.
5. They should have very low percentage of water absorption.
6. They should give a clear ringing sound when struck with each other.
7. They should show good resistance to abrassion.