Construction Knowledge (Masonry) Series: What is a “Bond Beam”?

A Bond Beam is a type of Concrete Masonry Unit (CMU) with a notch running through it designed to accommodate placement of horizontal rebar.  The rebar is simply set within these bond beams.

CMU Walls are typically designed with horizontal and vertical rebar and then filled with grout to reinforce the CMU block.  Standard CMU blocks do not have any room to accommodate rebar which is why bond beams are used in lieu of standard blocks at courses with horizontal rebar.  From both the outside and inside, the wall looks as if it is made of the same standard type block.

As you can see from the photo, bond beams cannot be used on corners.  At corner locations with horizontal rebar, standard blocks can be modified (cut) so that there is a solid exterior shell with notches that accept rebar.

Bond beams are also helpful in providing a horizontal pathways for grout to flow.  This helps ensure fully grouted walls with no voids.

In case you were wondering how vertical rebar is installed, the rebar is simply dropped/placed through the webs right before a lift of grout is set to get poured.  Easy!