What is flammability? Why do builders avoid using flammable materials in homes?

It can cause a fire and because if there is a flammable thing it can catch on fire FAST!

The ability of a substance to readily catch fire or ignite in order to cause fire is known as flammability.

Builder use non-inflammable materials while building a house. These materials include gypsum, Portland cement concrete, silica etc.

These non-inflammable materials are used by builders in order to avoid any accidental fire in the house which can lead to loss of property and also the loss of many human lives.