Causes of Surface Decay
Surface decay can result from several factors, including:
- Weathering: Over time, exposure to the elements can cause stones to deteriorate.
- Improper Materials: The use of cement materials around or covering the stone can accelerate decay.
- Incorrect Bedding: Stones should be laid with their layers horizontal and facing downwards. If built on the wrong bed, with layers vertical and facing outwards, the stone is more susceptible to freeze-thaw action and natural delamination.
Superficial surface decay may be repaired. This is a cost-effective way to restore a stone’s structure and longevity. Although a properly applied repair can last 10-20+ years, it is temporary and will eventually detach from the original stone. For this reason, we usually avoid repairing stones directly over walkways and doorways, especially at higher levels of a building.
A stone with surface decay exceeding 10mm from the original face should be replaced. Lithomex is designed to bond to stone with a coat no thicker than 10mm. It also has to be applied to a solid surface; therefore, a soft, crumbling stone should always be replaced. This is commonly referred to as internal decay.