Stone is one of the oldest building materials, and provides a long-lasting, classic look that other materials can't match. However, building with stone can also be a labour-intensive and difficult process. There's more to building with stone than just stacking up rocks. Learning about the major building techniques for stone walls can help homeowners make the right decision for their needs and resources.
Dry stacking is the simplest technique for building stone walls. Rocks are simply stacked without mortar into a wall. However, it's important to place the stones carefully. According to "Stonework: Techniques and Projects," stones in dry-stacked walls should stay in place due to gravity and friction, but should be placed deliberately. These walls also require large, flat stones that reach all the way across the width of the wall, called tie-stones. Tie-stones prevent the wall from coming apart as the ground freezes and thaws under it. Drystone walls may be built using shaped stones or by carefully selecting natural stones that fit closely together.
A stone wall constructed with mortar is stronger than a dry stacked wall, but is more than just a dry wall with mortar in the joints. Unlike a dry stacked wall, mortared walls are inflexible and can't move as the soil does. This means that mortared stone walls must be built on a footer that extends below the frost line. This can be constructed from gravel or concrete, and requires extensive digging. Ideally the footer should extend several inches beyond the width of the wall. A mortared stone wall's greater strength means that it can be narrower than a dry stacked wall, without danger of tumbling.
Many modern stone walls are not actually stone all the way through. Instead, these walls are constructed from reinforced masonry, such as concrete block, with a nonstructural layer of stone on either side. This type of wall can be built much more quickly than traditional dry-stacked or mortared walls, and requires much less skill to put together. Like a mortared wall, veneered stone walls require a footer to support them. They're assembled by first erecting the internal structural wall, which includes metal tabs to tie the stones to the facing, then stacking a veneer of stone to hide the brick. The stones are mortared both to one another and to the wall's masonry core.