Complex sentence: In the 1970s, some housing councils would attempt to deter squatters from entering their properties by "gutting" the houses, rendering them uninhabitable by pouring concrete into toilets and sinks or smashing the ceilings and staircases.
Split into simpler sentences: In the 1970s, some housing councils would attempt to deter squatters from entering their properties by "gutting" the houses. "Gutting" refers to the process by which empty houses are rendered uninhabitable by pouring concrete into toilets and sinks or smashing the ceilings and staircases.