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Block-Laying Basics

Cutting Masonry Units

O ne way to cut masonry is with a brick hammer and chisel, but it’s an inaccu- rate and wasteful method that I use only for very rough work. Large, stationary masonry saws do a terrific job, but they’re expensive and a hassle to move and set up. Most of the time, I use two relatively inexpensive tools that are light and portable, yet produce excel- lent cuts. The first is my Elmer’s Midget Helper (about $400; E&R Mfg. Co., 765/279- 8826, www.ermanufacturing.com), a portable brick-splitter I’ve owned for more than 25 years. Pulling down on its handle compresses the brick between two hardened blades; the tool works great for cutting bricks to length and for making the angled cuts needed for window sills (see photo, below).

To cleanly and accurately cut — rather than break — brick and block, I use a dry-cutting diamond blade attached to my 412-inch grinder (blades are available to fit circular saws as well). This technique creates a lot of dust, so I use a high-quality dust mask. The 412-inch blade cuts only about an inch deep. With brick, though, I can usually finish the cut by making another pass on the opposite side of the brick. With block, I can usually break the block cleanly along the cut by tapping it with a hammer.

This portable mechanical cutter — which weighs only 35 pounds — can be used to accurately break brick, stone, and concrete products.

some of the techniques you need to confidently lay concrete block and brick. Except for the size of the units, there’s not a lot of difference between working with brick and with block.

Lay Out to Avoid Cutting

Bricks and blocks are hard to cut, so it pays to think in terms of unit sizes when laying out masonry work. Since the 1930s, masonry units have been manufactured in sizes that fit into a modular scheme based on 4 inches. So while a standard block

55 is 7 ⁄ 8 inches high by 15 ⁄ 8 inches long, adding a horizontal

joint below (the bed joint) and a vertical joint on one end (the head joint) brings the unit to an even 8 inches by 16 inches.

15 A standard modular brick measures 2 ⁄4 inches high by 7 8

inches long. Three courses of brick with three bed joints add up to 8 inches in height, while a single brick with a head joint is 8

inches long.

Because they can be adjusted in size slightly, mortar joints provide some layout flexibility. While the ideal mortar joint is

31 8 inch wide, masons routinely shrink joints to as small as 4

1 inch or stretch them to as large as 2 inch. Joints that fall out-

side this range are unsightly and, with a few small exceptions,

prohibited by most building codes.

Masonry units can be cut to length when necessary to fit around windows and doors or to build a foundation to precise dimensions (see “Cutting Masonry Units,” left). But cutting them along their length — what carpenters would call ripping

  • is another matter altogether. To avoid this aggravating job,

masons usually begin course layout from the top, establishing a finish elevation and then measuring and marking down, in

full courses, from that point.

In the small shop building shown here, for example, the refer- ence point for the foundation was the projected top of the slab, which my client wanted a few inches above grade. Using batter boards, I set a string at this elevation for reference, then dug and poured the reinforced footing so that the top surface of the con- crete would end up two full block courses and two full brick courses down from the string (see Figure 1, page 3).

Choosing the Right Mortar

Probably nothing is more confusing to the lay mason than mortar mixes. And it’s not hard to see why: There are three dif- ferent kinds of mortar available for brick- and block-work: cement-lime mortar, masonry cement mortar, and the awk- wardly named mortar cement mortar.

Although they look pretty much the same, these are dis- tinctly different products. Each can be made into four types of mortar, designated by the letters M, S, N, and O (taken from the


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