Yes, you can. However, it’s recommended not to go for the default method of application if you’re intent on doing so. Timber is a construction material that is highly flexible, and it expands/contracts depending on changes in moisture and temperature. This will cause the roughcasting to crack.  There are three methods that we recommend if you’ve got your heart set on roughcasting timber:  Cladding – Installing a layer of exterior-grade cladding can give the roughcast protection against the timber frame’s movements.  Timer-compatible Render – This means that you’ll have a type of roughcast that will respond accordingly to the movement of timber, reducing the risk of cracking and delamination.  Breathable renders – Breathable renders will allow you to improve thermal performance as well as having a render that is compatible with a roughcast finish, as these systems help manage moisture and prevent condensation.