water molecule

H2o is the name given to the water molecule, which is only 0.275 nanometres in size, and billions of them are needed to create a droplet.liquid water contains billions of water moulculs

Water is unique as in the earth’s climate; it occurs in three forms: 

1. Vapour.

2. Liquid.

3. Solid (ice, snow).

It is a universal solvent which has an effect on building defects/dampness due to salt movement.  

Different materials in a building can absorb water at high humidity and release it at times of low humidity. The amount of hygroscopic moisture a material can hold is variable, but salts increase moisture retention.  It is why building professionals discuss the ability of a buildings ability to buffer moisture.