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A Brick Wall on a Block Foundation

A freestanding brick wall more than 4 feet high requires lateral support against wind and climbing children. The 8-inch-wide wall shown on the following pages is reinforced with square pilasters that measure 16 inches per side. The footings are 24 inches wide and 10 inches deep. However, specifications in your area depend on the local building code.

A CONCRETE BLOCK FOUNDATION

Regardless of the type of wall you are planning aboveground, it is most economical to build from the top of the footing up to ground level with concrete block. Buy standard “stretcher” blocks measuring 8 by 8 by 16 inches. To avoid having to cut the stretchers, you will also need half blocks measuring 8 by 8 by 8 inches. Purchase flat-ended “double-corner” blocks and “partition” blocks measuring 4 by 8 by 16 inches for the pilasters as well. A few inches below ground level, lay the masonry units for the wall itself.

TOOLS Tape measure Chalk line Straightedge 4' level Torpedo level Shovel Mortar hoe Mason’s trowel Mason’s blocks and line Line pins MATERIALS 1-by board for story pole Mortar ingredients (Portland cement, lime, masonry sand) Premixed grout Concrete blocks Bricks Truss-type horizontal joint reinforcement

SPACING PILASTERS

For ease in positioning pilasters 8 to 10 feet apart, make the length of the wall and the distance between pilasters divisible by 8 inches. Fill the cores of the blocks in the pilasters with grout. For added strength, run two lengths of reinforcing bar down through the cores of the foundation blocks in each pilaster before filling them. No. 4 to No. 8 reinforcing bar is usually required, depending on the local code. Keep in mind that a pilaster is useful as a wall support only if it is perfectly plumb.

CUTTING BRICKS

With a mason’s chisel and a hammer, score a line on the brick at the point where you want it to break. Turn it over and tap the other side a few times. The brick should split on the second or third blow.

SAFETY TIP

Always wear safety goggles when mixing mortar, and long sleeves and gloves when working with mortar and concrete. Wear gloves and safety goggles when cutting bricks.

BUILDING A BLOCK FOUNDATION

BUILDING A BLOCK FOUNDATION

Aligning the blocks

Snap a chalk line 4 inches from the center of the footing to mark the edge of the bottom course of blocks (above); snap a second line 4 inches outside the first for the edge of the pilasters. Lay a dry run of blocks for the first course, aligning them with the first chalk line. Lay a pair of blocks at the appropriate interval for each pilaster. Leave a ⅜- to ½-inch gap between the blocks to allow for mortar joints. If necessary, adjust the thickness of the joints to bring the course to the correct length. Mark the location of each pilaster on the footing with chalk.

Starting the first course

Prepare a batch of mortar. As you build the wall, spread just enough mortar for one or two blocks at a time with a mason’s trowel. Lay two double-corner blocks side by side in a full mortar bed at one of the end pilaster marks. To gauge how much space to leave between the blocks, set two bricks end to end across the footing, aligning the end of one brick with the second chalk line and leaving ⅜ inch between the bricks. Lay the blocks so that their outside edges are even with the ends of the bricks (right), leaving about 1 inch between the blocks. Plumb and level the blocks with a 4-foot level. With a story pole made by marking the desired height of the blocks and the thickness of the mortar bed on a stick, check the block height. Make adjustments if necessary. Lay two more double-corner blocks for the other end pilaster, run a mason’s line (photograph) between the two ends, and lay the other pilaster blocks in position. Fill the cores of the blocks with grout.

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PREPARING MORTAR

Mortar holds masonry walls together, sealing out the elements and compensating for variations in the size of the materials. Pre-mixed bags of mortar are useful for small projects, but uneconomical for larger projects like the wall featured here.

Mortar is a mix of Portland cement, lime, sand, and water. The exact formula will vary with local conditions, particularly climate. Check with the code requirements in your area or consult local brick suppliers, masons, or contractors.

To prepare a batch of mortar, combine the dry ingredients in a wheelbarrow with a mortar hoe. Blend in the water—adding just the right amount to obtain a workable mix. To check its consistency, raise a series of ridges in the mortar with a shovel or hoe. If the ridges crumble, the mix is too dry. If they slump, there is too much water.

You can keep a batch of mortar workable for up to two hours by sprinkling water on it as needed and remixing. After two hours, prepare a new batch.

Completing the first course

Lay a stretcher block on the footing against each end pilaster and on both sides of the other pilasters. Center the blocks on the joint between the two pilaster blocks and align them with the inside chalk line. Once the mortar has begun to set, place a line pin in each joint between the pilasters and the stretcher blocks. Available at masonry suppliers, the pins will anchor a mason’s line to align the remaining stretcher blocks along the footing. Continue laying stretcher blocks (above), completing the first course. Remove the line pins and plug the holes they leave with mortar.

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Completing the foundation

Begin the second course with a half block at each end, centering the blocks over the joints between the pilaster blocks. Check the height of the block with your story pole. Lay a corner block inside each half block, run a mason’s line from one end of the wall to the other, and fill in between them with stretcher blocks. Lay partition blocks at each pilaster, sandwiching the newly laid second-course blocks (right). The partition blocks must be flush with the double-corner blocks beneath them. Lay the third course as you did the first, but at each pilaster, embed a 15-inch length of truss-type joint reinforcement in the mortar across the wall before laying the blocks. Once the mortar has set, fill the openings in the blocks at each pilaster with grout so that there is a continuous column of grout from the footing up to a few inches from the top of the third course. Continuing in this manner, build the foundation to within a few inches of ground level. Check the first block you set in each new course with the story pole.

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ERECTING A BRICK WALL

ERECTING A BRICK WALL

Making a dry run

Lay a dry run of the first course of bricks from pilaster to pilaster to check and adjust their placement. Lay the bricks in the pattern shown at left, starting with two end bricks set halfway into the core of each pilaster. Leave a gap of about ½ inch between the bricks. Lay bricks around the perimeter of each pilaster, ensuring they are flush with the outside edges of the pilasters. If the bricks project beyond the blocks, set them so the overhang is all on one side. Lay the remaining bricks of the run in pairs so their combined width equals the length of a brick (left). Again, locate any overhang on one side of the foundation. Mark the location of the end bricks on the pilasters, note the gap between bricks, and remove the dry run.

Laying the leads

Start the wall by building a lead—or end structure—six courses high at each end of the wall. Spread mortar on the tops of the end pilaster blocks and along 2½ feet of the adjoining blocks. Set a 10-foot length of joint reinforcement 1 inch in from the end of the lead. Following your dry-run pattern, lay a row of bricks around the rim of the pilaster. Lay the end bricks, aligning them with the marks on the pilaster, and add three more pairs of bricks along the wall. Level and plumb each brick with a torpedo level. Set a half block in the middle of the pilaster. Begin the second course, altering the pattern so each brick is centered over a vertical joint of the course below. Stop the second course a half-brick’s length from the end of the first. Start the third course, aligning the bricks with those in the first course, but make this row a full brick shorter. Set a 15-inch length of joint reinforcement across the pilaster (left), then begin three more courses of bricks, staggering the vertical joints between successive courses.

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Building up the pilasters

Lay 10-foot lengths of joint reinforcement along the top of the block foundation, overlapping their ends 12 to 15 inches. At each pilaster between the ends, build six-course double leads—ones that step up from the wall on both sides as described above. To help maintain horizontal alignment, stretch a mason’s line between the end pilasters. For vertical alignment, butt a straightedge against the bricks and foundation wall (right), tapping the bricks flush, as necessary. Fill the cores of the pilaster blocks with grout. Complete the courses between the pilasters, running a mason’s line from line pins stuck in the vertical mortar joints next to the pilasters. Fill in the soil you dug out for the footing trench and compact it well with a tamper.

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Extending the wall upward

Once you have completed six courses of bricks, lay joint reinforcement along the wall. Then, build six-course leads at each pilaster. Grout the lead cores, fill in the courses between the pilasters, and repeat the process, adding joint reinforcement after every sixth course. If you laid one or two courses of brick below grade, four six-course leads will take the wall to 5 feet; an additional three courses plus a cap will take it to 6 feet.

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Capping the wall

Once the wall is 4 inches short of the desired height, lay joint reinforcement along the top, build the pilasters up three more courses, and fill in their cores. Start with a dry run of rowlocks (bricks laid on edge) along the wall between the pilasters to determine the required thickness of the remaining mortar joints. Lay the rowlocks in a mortar bed (left).

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Capping the pilasters

For each pilaster, cut eight 1-inch-thick pieces of brick, called closers. These serve to widen the two courses that cap the pilasters. Cut the bricks as described on page 220. Lay the first course of the cap around the rim of the pilaster with full-sized bricks; follow the basic pattern, but ensure the bricks overhang the rim by 1 inch all around. Fit closers in the gaps between the bricks. Set two bricks in the middle of the pilaster and fill the gaps with mortar. Alternating the pattern, lay the second cap course flush with the first (right). Set two more bricks in the center. For the final course, center eight bricks across the pilaster.

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