Internal Quality

Internal-quality bricks are not suitable for external work due to a lack of durability when exposed to the weather. Some commons are of internal quality as are some facing bricks.

Ordinary Quality

Ordinary-quality bricks are those that are suitable for most external uses; however, some may not stand up to very exposed conditions or below horizontal DPC where they will be wet and susceptible to frost damage. Most facing bricks fall into the category of ordinary quality, as do many commons.