Homeowner Forum / Construction / June 2006

try using LxHx1.125, if you know what the approx height is going to be.
in example a crawl space footing with no stepdowns or bulkheads is
usally about 24" so that gives you 3 courses and usally you will have
one course under or at least partially under ground, if so that would
be a 4th course.  a concrete masonry unit(block)is 7,5/8 x 15,5/8 when
installed with a 3/8 motor joint gives you 8x16 face side of block. if
you have stepdowns or bulk heads in the footing as a result of uneven
terain it should only step in increments of 8" but more often than not
because of error in calculating sometimes it may be off a bit, but
easily solved by building up your mud bed, or cutting down your block,
and most often adjusting thickness of your mortor joint, and you should
shoot each corner as you build it up with a builders level about every
2 or 3 courses making sure you maintain the same elevation reading or
at least within 1/4" at all corners, and you should always build your
corners up and then lay your blocks to a taut line extended from the
corners lined up at the top edge of the blocks for that course and
repeat that step for each course and you will lay a true and even wall.
im pretty sure that formula will work , its been a while scince ive
estimated  for blocks but i think its right, there are a couple of
other formulas but i will have to dig them up.  if you know the lenght
of your footing you can multiply that times 12" and then divide by 16"
and you should get the total number of units per course and then if you
know the approximate height , then multiply the total per course by the
number of courses, each course will be 8" high. if you need to know
anything else about the construction of cmu units or anything else in
the construction industry residential or commercial you can email me
at(roykprice@gmail.com) and i will be happy to assist you. and if i
give you information that dont sound just right email me and i will
re-check my self .