Understanding Pressure Treatment Classes for External Timber — What UC3, UC4, and Others Mean
When purchasing pressure treated timber, customers will notice a Use Class designation, usually UC3 or UC4 for exterior uses. Use Classes indicate timber protection and applicable conditions. This information can usually be found on product specifications or labels. Many customers disregard this detail, assuming the number impacts the value of the product. This is false. Many customers do not notice Use Class UC2, resulting in a significant loss of value. Class identifiers are listed in the BS EN 335 European standard for timber durability and preservative. Classes run from UC1 to UC5, and each describes a different exposure scenario. Most homeowners are primarily focused on the middle of the scale. UC1 includes timber that will be indoors and in dry conditions, and with no chance of being wetted, such as... Read More »