Stucco is a plaster-like substance applied over walls for appearance and durability. It is occasionally used on interior walls but is mostly frequently used on the exterior of homes and buildings. The classic forms of stucco are very sturdy building materials and have been used for hundreds of years. However, stucco does need maintenance and repairs from time to time and doing it properly is critical to preventing further damage. Simple DIY repairs and maintenance can be successfully undertaken by a homeowner, but larger scale repairs should be performed by an experienced contractor.