A Solid Foundation

• Bricks are usually laid on a ledge of foundation that is poured when the house is built. A home with a wood-framed wall structure probably doesn't have the needed ledge, so a new one would have to be created. This often requires the services of a structural engineer to assess the best ways to support the new brick.
  
  

Waterproofing

• Brick is not waterproof. Moisture, and especially rain, can get inside this porous surface pretty easily, so it's important to make sure that the wall behind the brick has a heavy-duty water membrane. This will keep any water that gets through the brick from seeping into wooden materials and causing moisture damage and mold. This membrane has to overlap any flashing at each and every window or door, but it also has to be installed under the flashing.
  
  

Bricklaying

• Bricks take a lot of work to lay around doors and windows especially. Not only do bricklayers need to adjust the thickness of mortar joints, but also the structure of the brick itself. Different designs handle water better, channeling it away from areas where it could seep into the home. Some walls need to be convex and some concave and all of it needs the proper support of the brick below.
  
  

Cold Weather Considerations

• Guidelines for laying brick in cold temperatures are strict because of the worry that the water in the mortar will freeze before it has a chance to properly set. This can leave patches of brick unconnected to one another and to chipping, dry mortar. Additives can be added to the mortar to allow bricklayers to work them, even in slightly below freezing temperatures. However, these additives must be used exactly as instructed.
  
  

Thin Brick Systems

• While thin brick systems can be installed over existing side, they are also very exacting and some of the products are the market don't offer enough in the way of alignment possibilities. This means that on houses that are not perfectly level--as many older homes are not--there isn't much you can do to keep your bricks in a level line. Traditional bricklayers can adjust for this by using more or less mortar and compensating with the thickness of the mortar joints.