Masonry Wall Expansion Joints

[OneStepBehind]

I have a building that is 117' long with a 8" CMU wall that extends 12' AFF to a bond beam and a pre-engineered building above that. I am locating joints in the CMU wall and wondered if the joint should extend down to the footer? The foundation wall is also CMU and is just down to frost depth that is around 30" below grade. It seems to me that it should but I continually get into disagreements with others that don't think it needs to. Which should it be?

Thanks

 

[JAE]

I would extend joints down to the foundation. (footer?)

For concrete based block (i.e. CMU) they are control joints - not expansion joints.

Concrete block shrinks.

 

[OneStepBehind]

Sorry about the term "footer". It is local slang.
Thanks for your input.

 

[JAE]

If you have a joint that runs down the wall and then simply stops - the joint will continue in the form of a crack anyway - better to control and seal a good joint vs. a crack.

 

[shobroco]

A crack might continue down to the footing, but not likely. The shrinkage is a result of drying and thermal stresses, and buried foundation walls have pretty stable moisture contents & temperatures. If the foundation is completed and backfilled prior to construction of the above grade wall (as opposed to a continuously constructed wall), a damproof course should be inserted just above grade & the joints should start there. That serves to stop capillary action of moisture up into the wall and serves as a bond-breaker to allow the above grade wall to shrink and only crack at your joints. If you have a PEMB, I assume that the columns sit at top of foundation height and your CMU wall is replacing steel girts & cladding, not actually carrying the building.

 

[OneStepBehind]

You are correct shobroco. That is what I have in respect to the building. Thanks to all of you for your input.