Granite
Types and Durability
| Description
Granite and Other Igneous Rocks | Expected Lifespan
(Years) | Adjustment Factors |
| External | ||
| Natural granite and other igneous rocks specified and selected to BS 8298:1994.Test certification for specific batch delivered to site to show freedom from deep geological weathering. Performance and specification to be confirmed with supplier. | 35+ | 1st stage adjustment factor:
In industrial areas (heavy polluted): -15% years In urban areas: -10% years In suburban areas: -0% years 2nd stage adjustment factor: Contact with soluble salt: -30% years Within 20m from express way: -20% years Within 20m from major arterial road: -10% years Within 20m from light traffic road: – 5% years Quality relies on preservative or water repellent: -15% years Test certificate from approved local testing authority : +15% years |
| Natural granite and other igneous rocks specified and selected to BS 8298:1994. Certification to show freedom from deep geological weathering. Performance and specification to be confirmed with supplier. | 35 | |
| Unclassified, i.e. natural granite and other igneous rocks neither specified nor selected to BS 5390. | < 35 | None |
Combination of adjustment factors (1st stage and 2nd stage) should be added to obtain the durability values. Refer to durability calculator.
Note: A visit to the quarry is recommended to confirm selection of stone. In some cases durability may be assessed by inspection of stone blocks in the quarry. Selected stones should be identified and kept as samples indicating the range of variation which is acceptable. This section does not apply to stones used for non load bearing claddings.