Expert: Dan Griffin - 8/22/2009

Question
Dear Dan wehave a2 story block wall with brick veneer.the wall has 1 small door and no windows. surface area is 50 x 25. we want to put in a 6 foot door in the middle. We sure dont want to cut the opening and have all the brick and block land on us. Could you give us some advice how to cut through,which side to start on,size lintel etc. we really apprciate your help.

Answer
Tim, block and brick walls are quite stable and you can knock holes in them with little chance of wall failure.  I do NOT mean you don't need to pay attention to what it is your are doing.  There are many approaches to what you want to accomplish with slightly different end products.  The very best approach would be to accomplish the finish product in a manner closest to original construction.  You should be able to look at an existing opening and diagnose how they handled the block header and the brick lintel.  There are other ways to accomplish the task that may be "easier".  You are crossing several trades which makes this an awkward job.  A mason usually won't get involved with structural shoring, jamb selection/setting, and certainly not door and hardware installation.  A carpenter well skilled in doors and even the structural work will not be prepared to do the masonry work and may not be prepared to deal with lintels and bearing issues, drilling through the walls, demolishing block and rebar, or welding lintel iron.

Brick veneer and block joints line up about every 24 inches.  Things will be much easier if you make one of these the top of your new opening.  If you are headed for a steel jamb, you can get one with a 4" head (quite normal) that will course out with cement block.  A 3/0 x 7/0 standard commercial door and steel jamb will be 40" wide.  YOur block and brick wall will probably be between 11 and 13" thick.  Steel jambs can be had in several different widths and should be arranged for before starting the hole.  You can drill one small hole completely through the wall with a long masonry bit.  This will let you measure and layout the proposed opening on each side of the wall and know exactly where you are on each side.  The cement block wall will have horizontal trough blocks at 4 foot and 8 foot with concrete and rebar fill.  Finding the right person to coordinate the project can be difficult.  If you have someone in house that understands the issues, I think it can all be solved with a good mason.

2 pieces of 3x3x1/4 angle long enough to bear about 6" on each side of the opening should be adequate for carrying the brick and block, but you do have a second story load.  I don't know what is carrying the 2nd floor and some of  those loads may be bearing on this opening.  If the wall is carrying an edge of the second floor with a long 3x3x1/4 angle bolted every couple of feet, not much worry.  If the bar joist tails are bearing on your wall, they create a more concentrated point load and add concern.  3x5x3/8 angle is a bit harder to use.  Back to back C channel will carry tremendous loads.  All lintels must be longer than the hole so they transfer the loads into the walls.  Here is some good information.  If you don't understand what this page is telling about sufficient bridging above the opening, you should probably get some technical advice from a sturctural engineer:
http://www.google.com/url?sa=t&source=web&ct=res&cd=2&ved=0CBAQFjAB&url=http%3A%...

A really good mason should know all the issues and will have done this many times.

method 1
You can mount the angle irons face to face and bolt them through the wall or weld tabs to hold the bottoms together.  This will require removing most of the masonry in the opening, clearing the mortar off the  brick and block where the lintel will sit and grinding out the mortar at each side of the opening to get the lintels in position.  They will need to be at least 6" longer on each side of the opening.  The edges can then be sawed out or toothed out.  YOu can use a bolt in jamb or use wall anchors if you are relaying the sides.  This method will be difficult to flash and make look "original".

method 2
shore the floor loads over head.  Create an oversized hole to allow installing a block lintel, concrete lintel, or back to back steel lintel.  A trough block lintel on the inside with a loose steel lintel carrying the brick would be closest to original construction.  Relay sides holding the door jamb.  

The more I try to explain this, the more complicated it is becoming, as there are so many variables to consider.  I hope I have helped you to understand the issues and gotten you off to a good start.