Angled Sash Brush

• An angled sash brush is a brush with a diagonal cut along the edge of the bristles, meant to make sharp lines and reach hard places. Most people who have painted a room or a house in the past should have a quality angled sash brush in their painting supplies.
  
  

One-Inch Flat Brush

• A one-inch flat brush with stiff bristles, when turned on its side, will usually fit in the spaces between the bricks without a problem. This brush should be narrow enough to paint the grout but wide enough to paint the sides of the bricks as well.
  
  

Artist's Brush

• If you have a rounded or filbert artist's brush laying around, this may be used to reach any very difficult places between bricks. Artist's brushes, which are meant for precision work, are generally never used in home painting projects, but in this case you may find you like the control of the artist's brush. Use a brush meant for acrylic or oil paint -- not watercolor.
  
  

Foam Paintbrush

• A one-inch foam paintbrush will be stiff enough to reach even the toughest spaces between bricks. Don't use a foam paintbrush as the primary brush to paint the grout between bricks, because the bristles of a standard brush will coat small porous areas better. However, you can use a foam brush to reach narrow spaces where bristles keep getting caught on the edges of the brick.