Planning Brick Walls
Several brick projects are included: brick veneer walls, single-tier walls, garden walls, and lightweight veneers. All involve the same basic bricklaying techniques. The procedures used with bricks are similar to those used with concrete block walls, only the scale is different. Both types of masonry walls require you to learn the art of working with mortar. When planning a brick wall, check with your local building department for requirements regarding the type and size of materials you can use. There usually are standards as well for how the new wall should be attached to your house.
Make sure that a new wall rests on a solid foundation. Footings must be reinforced and extend below the frost line. Generally, a footing should be twice as wide as the wall it supports and its vertical thickness should equal the thickness of the finished wall. A brick veneer wall on a house, however, doesn’t necessarily need a new foundation; a solid ledge will suffice. Shown are some of the most common brick patterns—what masons refer to as bonds. Select a pattern, as well as a top cap if your project requires it. In addition, choose the type of mortar joint that best suits your needs.
Preparing Walls for Brick Veneer
Older homes often were built with double brick walls: two separate brick walls with a 1- or 2-inch air space between them. More common today is a single-width, or brick veneer, wall covering the face of a frame building. Although the brick wall is tied to the frame wall at various points, there is an air space between the two. This space can be filled with insulation. Such a wall is cladding only, not a structural element of the house.
Tools: Spacing rule, shovel, hammer, level, drill with masonry bit, pry bar or other demolition tools, circular saw.
1. Provide support for the bricks. Excavate a trench about 1 foot deep and at least 18 inches wide along the original foundation. To support the brick veneer, use one of the methods shown, either an angle iron or a concrete grade beam. Or you can use a wide concrete slab or concrete block foundation. If you’ll be bricking around any windows or doors, use a spacing rule to determine at what level the first course should be so a rowlock course of bricks can be positioned conveniently beneath the opening.
2. Prepare the house wall. Remove siding on the wall with a pry bar and cover the wall with construction paper or house wrap. The paper or wrap should overlap the edge of the steel angle or grade beam. To facilitate drainage, nail redwood or pressure-treated extensions to windowsills so they reach at least 3/8 inch beyond the new veneer. If possible, add 1 to 2 inches of rigid foam insulation between the existing wall and the new veneer. Remove window and door moldings, trim out with redwood or pressure-treated filler blocks, and reattach the molding. You may need to replace the existing molding with brick mold.
Laying Single-Tier Brick Veneer
Single-tier brick veneer is much like siding. It serves only as an outer finished shell whose functions are protection and decoration. A single-tier veneer wall supports only itself. It requires an air space between the bricks and the structure to vent moisture that builds up in the cavity. You also need a means of tying the veneer to the structure. Otherwise, the bricklaying techniques are essentially the same as for any brick structure.
Tools: Trowel, level, story pole or modular spacing rule, brick set for cutting bricks, baby sledge, hammer, jointer, brush.
1. Lay a bed of mortar. Install galvanized or aluminum flashing along the base of the wall. Before you mix the mortar, dry-lay a course of bricks and make required position adjustments. Mix the mortar and sprinkle or soak several bricks with water. On one end of the flashing, throw a 1-inch-deep bed of mortar long enough to lay two or three bricks. Furrow the mortar bed with the tip of the trowel, as shown.
2. Lay the first brick. Press the first brick into place, keeping a 1/2-inch air space between the brick and the wall surface and a 3/8-inch mortar joint beneath it. The air space helps insulate the wall and allows condensation to drain away. Trim excess mortar, returning it to your mortarboard or placing it farther down on the flashing.
Caution! Check alignment immediately after laying the first few bricks. If you wait too long, the bricks will absorb too much of the mortar's moisture to allow you to move bricks without the mortar crumbling.
3. Measure and align as you go. After you lay three or four bricks, measure the thickness of both the head and bed joints. They should all be 3/8 inch thick. If they aren’t thick enough, pull out the bricks, spread more mortar, and lay them again. Use a carpenter’s level to make sure the tops are level and even with each other. Check the face of each brick to make sure it is plumb. Finally, lay the level horizontally along the face of the bricks to make sure you are building a straight wall.
4. Build up the leads. Lay a bed of mortar and continue laying brick until you have built a five- or six-course lead at each end of the wall. Check your work often to make sure all the units are level, plumb, and aligned. Also check that you are maintaining a 3/8-inch-thick mortar bed.
5. Fill in the middle. Stretch a mason’s line between the corner leads. Position line blocks so the mason’s line aligns with and is about 1/16 inch out from the top of the first course of bricks. Lay the remainder of the bricks in the first course. Mortar both ends of the last brick in the course before setting it in the mortar bed. Move the line blocks and mason’s line up one course and continue laying bricks up to the mason’s line.
6. Add weep holes. As you lay bricks on top of the flashing, lay short pieces of 1/4 inch cord on the flashing about every 2 feet. Make sure the cords extend all the way through to the flashing. Once the mortar stiffens, pull out the cords to create weep holes. These weep holes vent moisture that builds up behind the brick.
7. Anchor the brick veneer. To tie the brick veneer to the existing wall, nail brick ties every 32 inches horizontally and 16 inches vertically. Stagger the rows across the wall so the ties are no more than 24 inches apart. Use 8d or 1 Od ring-shank nails or galvanized deck screws. Embed the ties completely in the mortar.
Building Corner Leads - When building a corner lead, you need to lay bricks going in two directions in an alternating pattern so the bricks will lock together. Keep this simple rule in mind: The number of bricks you lay in the first course should equal the number of courses in your lead. For example, if you want your lead to be nine courses high, lay five bricks in one direction and four bricks in the other. That will give you a base for a lead with nine courses.
8. Strike the joints. Using the jointer needed to produce the mortar joint of your choice, strike the head (vertical) joints first, then the bed (horizontal) joints. Strike the joints soon after laying the bricks. If you wait too long, the mortar will stiffen and be unworkable.
9. Clean with a brush. After striking the joints, let the mortar set up for a while, then remove the burrs and crumbs of mortar left along the joints. Use a stiff brush for smaller pieces and a trowel for larger ones. Clean off mortar smears with a dampened rag and a brush, taking care not to soak any mortar joints.
10. Install row-lock header bricks. To brick up the bottom of a windowsill or to cap off a veneer that extends only partway up a wall, set row-lock headers, as shown here, or headers that are laid flat. Install flashing and weep holes. You may have to cut the bricks or adjust the joints to make the headers fit.
■ Wherever a new masonry wall butts up against an existing wood, brick, or concrete surface, avoid bonding the two surfaces together firmly. Over the years, settling and expansion and contraction resulting from weather changes causes the two surfaces to move in different directions. Seal the joint between them with a material that is flexible.
■ Expansion joint material is made for this purpose. Secure it to the existing wall before you begin work, and butt your new wall against it.
■ Or, after the new wall is built, cram oakum (a plumbing material) into the gap. Finish with a thick bead of high-quality silicone, acrylic with silicone, or butyl caulk.
11. Install angle-iron headers. To support bricks that go over doorways and windows, secure a 3 1/2 x3 1/2 x 1/4-inch angle-iron header across the opening. Ends should rest on the course, even with the top of the opening. At least 4 inches of the angle should rest on the brick walls at both ends.
12. Cover top gaps with molding. If you brick all the way up to a soffit, cover the gap between the soffit and the top course of brick with molding. This not only gives the job a finished look, it also keeps out moisture and insects. Nailing can be tricky. Angle galvanized finishing nails into the framing behind the fascia or straight up into the fascia itself. Caulk the seam between the molding and the brick.