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Re: Masonry Expansion Joints

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I note with interest your expertise on masonry buildings. I am curious about 
the real need for expansion joints on large commercial retail warehouses in 
Florida eg Home Depot, Builders Square etc. I have found that most rely on 
the control joints at +/-30 ft o.c. with a tendency for expansion joints at 
+/- 250 feet o.c. The National Concrete & Masonry Association says the 
biggest problem they hear about is shrinkage rather than expansion as the 
blocks dry out during the initial periods. Our calculations indicate up to 
one inch expansion for masonry over one hundred feet for a seventy degree 
temp variation. The real world is strange in that common "verbal design 
experience" states if a building takes up more than one sheet then an 
expansion joint is needed! I was seeking a more scientific approach. However 
it appears the construction world will continue to make the control joints 
serve as expansion joints. I wonder what happens after the filler is 
compressed and does not expand again. I would welcome any comments. Thank 
you. Andrew Pyper, Florida