Main causes for deterioration of stones

The following are the main causes for deterioration of stones:

1. Alternate wetting and drying.

2. Alternate freezing and thawing.

3. Deleterious substances present in the air such as in the atmosphere near the seashores and industrial areas.

4. Living organisms, growth of vegetation (like seedlings of banyan trees that grow from droppings of birds) and living worms or bacteria that live in the stone can cause decay.

5. Movement of chemicals between materials. This occurs when limestones and sandstones are used together. The granular limestone can absorb magnisium sulphate present in other rocks if they are used adjacent to the other.

6. Nature of mortar. If the mortar has chemicals, they can affect the stonework.

7. Temperature variation. Large variations of temperature and alternate heating and cooling can cause expansion and contraction which cause cracking of stone.

8. Waterfalls and rainfalls. Falling of water from great heights or falling of water containing chemicals (like rainwater absorbing gases from the atmosphere) can cause deterioration of stones.

9. Wind. Winds blowing for a long time can over deserts contain sand and dust, which passing over the stones for a long lime can cause their deterioration.