Expert: Bruce E. Johnson - 8/31/2009

Question
I have just read a reply posted by you (from 2007) regarding supporting overhead brickwork whilst removing part of a load-bearing wall.
I have a similar project, in that I wish to remove about 5 feet span of single-brick thickness wall, adjacent to an existing doorway, to widen the opening out to about 8 feet. I will need to remove the existing door frame and replace the lintel out to 8 feet, plus the 4-inch overlap inserts at each end that you refer to. About 4 or 5 course of brick will remain in place above the new lintels, with just roof trusses supported above that.
You give me heart in saying the remaining courses should support themselves during removal of the wall and until a new lintel is installed.
My question is: What is a sensible limit to the span that will support itself (ie is 8 feet OK?): and, do I insert new mortar onto the top surface of the lintel to take up slack in the future suppport of the remaining courses.
I have also noted the use on a of concrete lintels, about 4 inches by 4 inches, rather than steel L-bars. I would prefer to use one of these as it will be easier to hide with render when I plaster the new work, I figure a steel lintel will stick out proud of the brickwork. Or perhaps I could use an I-beam and encase it?
Any guidance you can give me would be much appreaciated. Thank you, Peter Wheeler

Answer
Hi Peter, you can use a concrete lintel no problem.  Just make sure that you have at least 4" of bearing on each end of the lintel.  As I have mentioned before, brick and block will self support up to a point, it depends a lot on how much vibration and movement the masonry is subjected to during the demolition process.  A nicely cut wall will stay intact longer than one whose opening is created using chipping hammers or sledge hammers.  I personally have no problem opening up a wall and installing a lintel without shoring because I know what to look for and know how the wall I am working on is built.  However, I cannot say for sure how much of a span your wall is capable of handling before it begins to cave in.  If your wall has a bond beam at the top two or three courses then I wouldn't have any qualms about removing the opening up to 8 feet or even longer.  I use professional concrete cutting companies that have the proper saws capable of cutting through the entire wall depth in one plunge of the blade.  They also have concrete chain saws to clean out the corners without over cutting.  You can do the top horizontal cut first.  If the masonry stays in place without binding the saw blade then you can be rather assured that the masonry will stay together during the lintel replacement process. I always have everything ready to go to make the process as quick as possible.  In response to your other question, yes, you can make or buy a grout bag which you can use to pump mortar into open gaps or you can point up the mortar using a pointed trowel forcing the mortar into the joint.  I hope this information helps please feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com