Water is very heavy – 1,000 litres or one cubic metre weighs one tonne. The weight of this can have a significant impact on the stability of any structure, building or vessel. For example:
- Where a roof is involved in fire and the roof timbers burn through to the degree where they cannot support the weight of the roof covering, the roof will collapse to the floor below and the weight of the roof structure and firefighting water will impose a load that may be too heavy for the floor to support and cause further collapse. Refer to Fires in buildings – Unstable structure: Fire
- If water is lying on a lath and plaster or boarded ceiling it can put a strain on the fixings of the laths to the joists and the keying of the plaster to the laths
- In churches and cathedrals, fan-vaulted ceilings have conoids in the roof spaces, which can fill with water and fail catastrophically. Some cathedrals have a weak panel fitted that will fail when water fills the conoid to avoid collapse, but this is not a commonplace feature, so care should be taken to avoid filling them with water.
Also refer to Transport – Stability of the vessel.