Creating an Opening in Solid Brick Wall for HVAC Ductwork
I am in the planning stages of a small addition to our 1930s Washington, DC brick rowhouse. The walls are double wythe brick.
For the purposes of the addition, we will need to bring electrical, plumbing (both supply and drain) and HVAC from the existing house into the new section. I am not worried about the electrical or even the plumbing as the holes are relatively small, less than 4" round, but I am nervous about the HVAC because it requires a larger opening.
To accommodate the addition I need approximately 300 cfm of supply, so I will need to penetrate the brick wall with either a 9" round duct or a 8"x8" rectangular duct, so the hole would need to be a bit larger, of course.
Is this too large? Would such a penetration require a lintel? Any suggestions?