Stone Work Survey

Stone will deteriorate by acid attack:

• CO₂ in air when dissolved in rain water forms a weak acid solution,
• Sulphur dioxide SO₂ formed when sulphur is burned in the air mixes easily with rain water and forms Sulphurous acid H₂SO₃₎
• Nitrogen Oxides from car exhaust and power stations are other culprits

– Therefore it is essential that all stone work is regularly maintained and expertly decorated paying particular attention to prevent damp penetration.

Additionally, some  stone work, for example  door surrounds, are attached  by ferrous ties which can rust. If the gap between the stone work and the wall is not adequately weathered damp will penetrate between the wall and stone work; this can freeze during winter and create a ratcheting effect which can result in the heavy stone work becoming detached and falling. 

This risk can be aesthetically and sympathetically negated by the use of lead.