Expert: Dan Griffin - 7/31/2008

Question
The code doesn't specify reinforcement for CMU foundation wall if the wall height is less than 6 ft, does this mean CMU foundation wall can be done without reinforcement if the height of the wall is less than that? If yes, do we need to grout it or make it solid? if yes would be all courses or the 2 top courses only? Thanks for your help

Answer
Mariamagrama, I am curious about your name, it begs some explanation.  Structural design is not meant to be provided by code.  Your CMU walls will certainly need reinforcement.  The inspection department may well require  an engineering stamp on the design.  It would be typical to have a minimum of 2 #5 bars in a footing at least twice as wide as the block.  I don't know what you are putting on the wall, a house often requires 12" block dependent on loads and depth.  There will be vertical reinforcement at all corners, each side of any  openings, and at least every 4 feet.  There will be horizontal reinforcement at the bottom course, the top one or two courses and at least every 4 feet.  A reinforced vertical block cell usually requires one #5 bar with the cell slushed solid with concrete - NOT mortar!.  The horizontal beams require two #5 bars slushed solid with concrete.  This requires what is known in the trade as trough blocks which have cut and easily removed webs.

Any competent mason should know all the requirements.  The local block supplier may be able to provide a drawing suitable to submit for plan and review.