Bricks, Masonry, Asphalt and Concrete - Help: need hole in masonry wall for dryer vent

I need to cut a 4" round hole in our exterior masonry (brick) wall so that I can vent a dryer to the exterior. Our house is 100+ years old and the exterior walls are made of 3 (?) layers of brick. What's the best way to make the hole and any special things I should watch out for?

-Carmel in DC

Go to your local tool rental center and explain what you want to do. They will undoubtedly have what you need. It'll probably be a hole saw kit with some sort of hammer drill.

I would drill a series of small holes, say 1/2" or 5/8", with a rotary hammer drill around the outer edge of the hole you want and a some inside this circle...Most Rotary hammers come with a hammer only option which you can use with a chisel bit to remove the brick from this area...Then slide your vent into the opening making sure of course your sleeve is long enough to penetrate the inside of the wall...Lastly mix up some mortar and seal around the opening on the inside to stabilize it and caulk around the vent on the outside.

You won't get a hole saw, you will get a core driller and they are pricey to rent. I vote for the hammer drill and chisel method. Drill the holes as close together as you can so you have less of a chance of cracking the brick when chiseling it out.