Expert: Bruce E. Johnson - 11/6/2008

Question
QUESTION: Hi Bruce, I am adding a door to a cinder block wall, 8x8x16 block size, single story, truss construction. I  plan to over size the rough opening and lay ground face 8x8x8 block on both sides. I plan to place a short glue lam on both sides as the lintel. Can you give me advice on the do's and don't of this. And it seems that I was told once that wood and masonry together is something to stay away from because the wood expands and cracks the masonry.

ANSWER: Hi dave, I don't think using a wood beam in a masonry wall is a big deal. But I am wondering why you need a beam anyhow.  Most masonry walls have bond beams (the top two courses are U-block with reinforcing steel and filled with concrete).  If your door height is a standard 6'-8" and your wall height is 8-0 then you already have a reinforced header in place.  Now if the door you are installing is over 4 feet wide then you may need to install a piece of steel angle for added strength but I don't know how wide your new door is going to be.  I would caution against cutting out the bond beam and replacing it with a wood beam because by cutting the reinforcing steel in the bond beam your wall is going to lose some of its lateral integrity.  I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com


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QUESTION: The door is going to be custom, and the size is totally our choosing, we plan on a  60" wide pivot door. The wood beam was chosen for the appearances, not for structural considerations, and sorry I didn't say that first time around. But it sounds like if I cut up to the bottom of the bond beam, put in steel angle for the width issue and then install my wood piece below in whatever space is left. Dose that sound like a good plan to you?  

Answer
Hi again dave, okay that makes more sense.  If you leave the bond beam intact and can get your wood beam underneath it then you really shouldn't need an angle.  If possible try to protect the wood from the concrete with either metal flashing or felt paper wherever the wood touches the concrete.  Masonry has a tendency to get moist and that moisture however slight may eventually hurt the wood beam.  As far as exansion differences between the wood and the masonry if you can allow a quarter inch at each end of the beam you should be fine.  This joint can be caulked if needed.  I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com