Cracking of mortar joints in new cmu wall
Cracking of mortar joints in new cmu wall
(OP)
I have a newly constructed building with cmu walls. The building is approximately 250 feet long by 24 feet wide with a roof overhang of 8 feet on all sides. The top of cmu walls are 8'-8" above finished floor elevation. Window openings are 4 feet wide and are spaced at every 4'-8" on center. Two cores are grouted and reinforced on each side of each opening as well as one core between each opening. Vertical control joints are spaced at approximately every 16 feet and each adjacent core is grouted and reinforced. Type S mortar was used.
There are a lot of vertical cracks in the mortar joints right where the mortar bonds to the block. What could be causing these cracks? Is it happening because there is too much grouting and reinforcing in the walls? Should there be more control joints?
Thanks!!!
There are a lot of vertical cracks in the mortar joints right where the mortar bonds to the block. What could be causing these cracks? Is it happening because there is too much grouting and reinforcing in the walls? Should there be more control joints?
Thanks!!!






RE: Cracking of mortar joints in new cmu wall
A 16" long block with one core and 2 webs at 8" o.c. provides perfectly aligned grouting.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Cracking of mortar joints in new cmu wall
RE: Cracking of mortar joints in new cmu wall
if the wall was built in the super cold, and now it's not, it could be temperature differential.
Please remember: we're not all guys!
RE: Cracking of mortar joints in new cmu wall
Up close picture attached. Typical throughout building.
RE: Cracking of mortar joints in new cmu wall
How were the control joints detailed? Did the contractor happen to continue the horizontal reinforcement through the joint?
RE: Cracking of mortar joints in new cmu wall
With joints at 16 ft. o.c. I can't see how the overall wall shrinkage could be the direct cause.
If the joints weren't made properly and still had some through-joint connectivity, then perhaps some overall wall shrinkage cracks might occur.
This usually is the case in top-of-wall bond beams where the reinforcement was continuous.
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RE: Cracking of mortar joints in new cmu wall
Dik
RE: Cracking of mortar joints in new cmu wall
There is a bond beam at the top with (2) - #5's continuous through the control joints.
Yes, cracks are minor, but there seems to be a lot of them. The mason claims they are a result of the amount of vertical reinforcing and grout in the walls.
RE: Cracking of mortar joints in new cmu wall
Do a Google search and there is plenty out there on mortar shrinkage. Here is one.
tps://link.springer.com/article/10.1007/BF02481617?no-access=true
RE: Cracking of mortar joints in new cmu wall
Please remember: we're not all guys!
RE: Cracking of mortar joints in new cmu wall