The requirements of an ideal materials for damp proofing are:
1. It should be impervious.
2. It should be flexible.
3. It should be easy to carry out leak proofing joints.
4. It should be stable.
5. It should be durable. Its life should be as much as the life of building itself.
6. It should resist the load safely.
7. It should not contain sulphates, chloride and nitrates.
8. It should be cheap.
