Indirect Cylinder
A hot water storage cylinder which is heated by a coil of pipe served by a boiler. The hot cylinder water and the boiler water are therefore kept separate.
Infill
Soil, rubble or builders waste used to bring ground levels up to the required height. Can compact over time.
Initial Shrinkage
Shrinkage movement that occurs as a result of the drying out of building materials.
Injected D.P.C
A 'Damp Proof Course' applied to a building after its construction, usually consisting of a silicone based material injected into masonry at high pressure.
In-situ
Means in its natural or original place. In building it often refers to elements that where formed in the place where they remain.
Inspection Chamber
Access point to underground drains for inspection and maintenance. May be of brick, concrete or more modern pre-formed plastic construction.
Insulation
Material designed to reduce the transmission of heat, sound, fire or electricity.
Interceptor Chamber
Similar to an 'Inspection Chamber' but with a trap and a bung to prevent foul air escaping from the main sewer.
Interstitial Condensation
See Condensation.