Roof is the most important part of the building. Thus, we can say without roof our building or house is incomplete. There are many types of roofs available which are classified on the basis of their shape and size. Hence, knowing your roof style also can help you to decide what roof material or shingle works is best for your home.

Some of the common roof types are as follows ;
1. Saltbox Roofs
2. Mansard Roofs
3. Gambrel Roofs
4. Pyramid Roofs
5. Hip Roofs
6. Cross Gabled Roofs
7. Flat Roofs
8. Bonnet Roofs
9. Skillion Roofs
10. Sawtooth
11. Butterfly Roofs
12. Curved Roofs
13. Domed Roofs

Pre-stressed concrete is a form of concrete used in construction. It is substantially prestressed during production, in a manner that strengthens it against tensile forces which will exist when in service. According to the construction methods there are two kinds of prestressed concrete :-
– Pre-tensioned concrete
– Bonded Post-tensioned concrete
– Unbonded Post-tensioned concrete

The three types of members in prestressed concrete are as follows:-

1. Neither allowing tension nor crack.
2. Allowing tension within permissible stress but cracking is not allowed.
3. Tension and crack both are allowed but within permissible stress.