Industrial building - These shall include any building or part of a building or structure , in which products or materials of all kinds and properties are fabricated , assembled or processed for example refineries , mills , dairies , industries etc.

Institutional building - These shall include any building or part thereof which is used for purposes such as medical or other treatment or care of persons suffering from physical or mental illness or disease. These buildings ordinarily provide sleeping accomodation for the occupants. It includes hospitals , sanatoria , orphanages , prisons , reformatories.

Insulation of sound - It is the control of noise transmission which is essential to minimise the disturbing effect of sound passing from one room to another through walls , partitions and floors or ceilings.

Integral damp-proofing - This consists in adding certain water-proofing compounds with the concrete mix to increase its impermeability.

Intercepting trap - This trap is provided at the junction of house drain (inspection chamber) and street sewer to prevent entry of foul gases from sewer into the house drain. This trap is thus provided to disconnect the house drain from the street sewer.

Intrados - Also known as Soffit , it is the under-surface of an arch.

Inverted arch footing - This type of foundation used to be provided for multistoried buildings in olden times. It is rarely done these days.