How To Remove Cracked Bricks And Repair Them

Synopsis: Bricks and mortar cleft with time. In this article, veteran stonemason John Carroll delves into the tools and techniques for repairing damaged brick masonry, including how to lucifer the colors of new textile to old, the type of mortar to apply, and how to repair a brick without replacing it.

Editor'south notation: This commodity was written before OSHA released their guideline virtually the dangers of breathing in silica dust when cutting or grinding masonry. Exist sure to protect yourself, your coworkers, and your clients if you take on a project similar this.

At that place are a lot of reasons people cull brick for a edifice fabric. It doesn't provide an endless buffet for termites or serve every bit a building site for carpenter ants. Woodpeckers do non delight in drilling holes in it. Information technology'south dimensionally stable, doesn't rot or burn, and never needs to exist painted. With all these things going for it, though, brick has an Achilles heel: It'southward hard and inflexible, and it cracks nether certain conditions.

Whether the cracks are acquired by movement, comparatively filled joints, or just too many decades of being exposed to the weather, the owners of brick houses in Durham, N.C., often call me to fix them. The reason they phone call me is because I do more than slop mortar into the cracks. I make an effort to match the colour of the existing mortar, and when bricks are cracked, I repair the cracks with mortar dyed to match the color of the bricks. I also prep the surface properly, use the right mortar, and go along the joints as neat as possible. After packing the joints with mortar, I tool them to match the contour of the joints on the balance of the wall. My goal is always to make the cracks disappear.

Why brick cracks

Masonry structures crack for several reasons. The showtime is because the footing or slab the masonry rests on moves. (Many older houses don't even take what we'd consider footings today; the structural brick wall rests directly on the soil.) The first building textile is not the footing but the soil that it bears on. Footings should exist placed on virgin soil or soil that has been mechanically compacted to reach the proper begetting capacity.

Water can crusade some otherwise sound soils to become soft and plastic, reducing their bearing chapters and resulting in differential settlement that cracks the footing. Saturated soil that freezes can push button sections of a basis upwards, or it tin push laterally on a below-class masonry wall. Another problem is that structures such every bit foundation walls and retaining walls are ofttimes underbuilt. Masonry that's subjected to strong lateral forces, such as those imposed by soil, should be reinforced with steel.

A well-planned system to drain water abroad from the foundation is essential. But the work of fifty-fifty the most careful builder can be undone later by changes to the grade around the house. Landscaping that piles up mulch and dirt a few feet from the house often holds water that soaks in and eventually causes cracks in footings and physical slabs.

Steel lintels support brick every bit information technology passes over windows and doors. Steel that is likewise small-scale for the bridge tin deflect, causing cracks in the masonry above. In addition to sizing lintels correctly, it's important that they touch the brick at each side of the opening and not be attached to the woods framing behind. Wood expands and contracts more than masonry. Fastening the lintel to the framing can crusade cracks in the bricks.

Rusting lintels as well tin harm bricks. Steel expands every bit it rusts, lifting the masonry. The stair-shaped cracks that run up and away from the top corners of door and win dow openings are commonly caused by this rust. The all-time style to avoid them is, in one case again, to manage the water. Lintels should be flashed carefully to keep them dry and to shed any water that gets behind the brick veneer.

Cracks are besides acquired past poor workman ship. Over the long haul, joints that are packed solid with mortar perform a lot bet ter when exposed to the elements than joints that accept voids under the surface. Although builders should have the steps described here to minimize movement in masonry struc tures, movement tin't be eliminated com pletely. At least some movement is inevitable, so repairs volition go necessary eventually.

Sizing up the job

When people phone call me to repair brickwork, my first task is to look closely at the area in question and determine whether the piece of work is going to be price-constructive or fifty-fifty feasible. In full general, I see three types of problems. The first is old mortar that's loose in spots and has some visible fissures and voids. In these cases, all that's needed is to grind out the mortar and repoint the joints.

The 2nd type of problem occurs when the brickwork has moved and created cracks, some of which run through the bricks. In this case, the homeowner has to make a dif ficult decision. The only way to ensure that the brickwork won't crack again is to address the cause of the motility. Since this often involves replacing a lintel, or even repairing a ground, addressing the root cause can be very expensive. On the other mitt, it may be reasonable to assume that a firm that has been sitting in the same spot for l or more years has done all the settling it's going to do. Managing the water around the foundation may be enough to terminate any further progress of the underlying cause, and just repairing the masonry becomes acceptable. I've made many repairs in such cases that have held upwardly well for over a decade.

The tertiary type of problem is when the masonry is falling apart and tin can't be repaired. A common example is brick stairs that were built without a physical basis. No amount of repointing tin can repair these crumbling structures, and I advise the homeowners that the all-time solution is to tear the whole affair out, dig and pour a proper footing, and build a new set of stairs. Brickwork on houses themselves rarely reaches this state because it's ordinarily repaired before and then.

I frequently see poorly done repairs. The mortar is ofttimes the wrong blazon and the wrong colour. It's smeared on the face of the bricks and finished in a manner that doesn't come up close to matching the joints on the rest of firm. Cracks that run through bricks are simply filled with grayness mortar. The repaired cracks might keep h2o out, but they are an eyesore. I often end up redoing these botched fixes as I work my style around the house repairing other cracks.

U se the right mortar

Mortar should be softer than the bricks so that small stresses are absorbed past the mor tar rather than damaging the bricks. Before the late 19th century, mortar was very soft, consisting of lime and sand, and worked well with the soft bricks of the fourth dimension. Beginning in the late 19th century, improved kilns and manufacturing techniques created harder bricks, and portland cement became com monly bachelor. Mod mortar always contains portland cement and sand, which sets up harder than straight lime mortars. To ameliorate workability and soften the mortar, masons add hydrated lime to the portland cement. In the 1920s, masonry cement came on the marketplace. Masonry cement contains portland cement just uses proprietary ingre dients in place of site-added lime.

Varying the ratio of portland cement and lime (or the proprietary ingredients in masonry cement) to the sand yields different classifications of mortar with dissimilar com pressive strengths. Both portland-cement/ lime mortar and masonry-cement mortar are classified in three types: Thou, S, and Due north, with Blazon Yard existence the hardest and Blazon Northward the softest. An even softer mortar, Type O, is not bachelor as a masonry-cement mortar and can be made only by mixing portland cement and lime. To repair cracks in brick walls, Type Northward is considered ideal for almost buildings built after 1900. For historic buildings with soft bricks, Type O or lime mortar without portland cement is commonly specified.

Type M, Type Southward, and directly portland-cement mortar with no lime shouldn't be used to repair cracks in brick walls. They are hard and inflexible, adhering to the bricks so tenaciously that the slightest movement can cause the bricks to split and spall.

Clean out the old mortar

The first pace in repairing a crack is to grind out the former mortar. Joints should exist basis to a depth that's twice their width (usually 3⁄4 in. to 1 in.). The tools I use depend on the hardness of the mortar and the bricks too as the overall integrity of the wall. Old bricks can be fragile, and I work according to the maxim "First, do no harm." Mortar never comes out consistently. In the course of grinding and chiseling, the mortar farther dorsum in the joint often breaks and crumbles. That's not a problem; I only fill the deeper space with mortar during the side by side stage of the chore, actually getting a amend repair in those areas.

Use a rotary hammer on vertical joints. With a generally sound wall, setting the tool in hammer-but manner and using a chisel bit makes quick work of mortar. If the wall is frail, the chisel may be too aggressive. Instead, perforate the articulation with a 1⁄iv-in. drill chip and the tool set in hammer-drill style.	A tuck-point grinder makes quick work of horizontal joints. This 5-in. grinder uses a 1⁄4-in.-thick blade to grind out most of the mortar in one pass. Its dust port attaches to a vacuum, which collects most of the dust. The grinder isn't for working on vertical joints because it would cut into the bricks in a higher place and below.
Clean the drilled joints with a cold chisel. Don't chisel straight in or you'll risk loosening the bricks. Rather than pounding the chisel, just tap it and take out a little mortar at a time to avert damaging the wall.	Vacuum out the loose material. The new mortar won't stick well to loose crumbs. Employ a fissure vac attachment to reach deep into the joints.

dampening the area of the broken bricks — **Dampen the area to be patched.** Extremely dry masonry surfaces suck the moisture out of the mortar, preventing a proper cure. Spray the surface and then that information technology'south good and wet but not so that you inject a large amount of water behind the brick veneer. Let the surface dry so that the joints are withal clammy inside just there'southward no water on the surface of the bricks.

Make the mud to match

A common error is mismatching the mortar color. Achieving a perfect match is hard; sometime mortar tin display a range of shades, and sometimes it was dyed. Prior to the 1960s, portland-cement/lime mortars prevailed and tended to be light tan in color. Masonry- cement mortars have gained popularity since and so and are more often than not greyness but likewise come in white, tan, and buff. You lot can get a good match by making samples using mixes from different manufacturers and letting them harden for a week or so; mortar lightens every bit it dries. When standard materials don't match, I bring a
clamper of the mortar to Custom Match Colors (custom matchcorp.com), a local company with scores of powdered mortar dyes. If I become close to the existing color, then time, dust, pollen, and algae make small differences disappear.

Make samples to match mortars. The writer sets five or six samples that come close to matching the mortar in front end of the wall, so stands back to come across which matches all-time.	Use Type N. Blazon North mortar tin be made by mixing 1 part Type N masonry cement with 21⁄4 to 3 parts sand; or past mixing i part portland cement, nearly one role hydrated lime, and the sand. Add dye according to the manufacturer's instructions.
Mix a dry mortar. Start with a small amount of water, and mix to make a moist only crumbly mixture. Add more water gradually mixing until the textile sticks together in a smooth glob.	Place a 1⁄2-in.-thick layer of mortar on a hawk. Shake and tap the hawk to help the mortar stick and not slide off. As it dries, mortar grabs the surface of the hawk. If the mortar is wet, spread information technology out so that it dries to a better consistency.

Fill up the joints

To transfer the mud from the hawk to the wall, I use tuck pointers in several widths ( 1⁄4 in., 3⁄8 in., ane⁄ii in., v⁄8 in., and 3⁄4 in.), choosing the widest that will fit in the joint I'k filling. When possible, I work directly from the hawk. Just sometimes there are obstructions such as sills, or it'southward besides close to the ground to concord the hawk, then I transfer the mud on the constrict arrow. I apply the mud in layers and allow each to set up a flake before applying the next. I keep until the joints are packed total.

For conveying the mortar to the joint, I utilize the tuck pointer to cut a one⁄2 -in. strip of mortar on the hawk. I brand a long motility of pulling the mortar forth the surface of the militarist. This adheres the mortar to the constrict pointer so that I tin carry it to the joint without dropping it. I keep a 4-in. brick trowel handy for patting down and shaping the mortar on the hawk; this helps continue the pancake of mortar together and at the right thickness.

carry the mortar with the tuck pointer upside down when repairing broken bricks — **one** Acquit the mortar with the tuck pointer upside down.

rotate the tuck pointer into the joint of the broken bricks — ii Rotate the tuck pointer into the articulation.

pack the mortar in layers — **iii** Pack the mortar in layers.

using a brick trowel for short vertical joints — **Dissimilar joints take different trowels.** While the tuck arrow's length is an advantage on horizontal joints, information technology can be a liability with the shorter vertical joints. A four-in. brick trowel's shorter length is useful here.

working the mortar directly from the hawk to repair broken bricks — **Work direct from the hawk if you tin can.** On long, direct runs, it's most efficient to set the edge of the hawk at the bottom of a horizontal joint and use the tuck pointer to button the mud directly into the joint.

Finish the joints

Information technology's as important to match the profile of the repaired joints with those on the balance of firm as it is to friction match the color. Mortar joints can exist finished in several ways. To start, afterwards setting up slightly, joints can simply be cutting flush with the face of the bricks so brushed with a soft castor to texture them and blend them into the edges of the bricks. They also tin be raked back about one⁄4 in. from the surface. The articulation raker is a special tool for this that helps to maintain a consequent articulation depth, but yous also can rake out the joint with a tuck pointer.

Fill up the joints to the brim. This packs the mortar in, helping to keep h2o out and to ensure that each brick is fully supported.	Rake out the excess. Many mortar joints are recessed from the face of the brick. A joint raker holds a common nail at the desired rake depth and uses the nail head to scrape out extra mortar.
Tool the joint smooth. To match these existing joints, all that's needed afterward raking is to smooth the mortar with a tuck arrow.	Make clean up. Afterward the final tooling, use a soft-bristle brush to remove whatsoever stray mortar.

Finishing options. A third way to terminate joints is by using a jointing tool to shape the mortar. In that location are many different jointing tools that can mold joints to a multifariousness of profiles, including concave, Five-joint, weathered, beaded, and grapevine.

shape to match existing brick joints — **Shape as needed.** Matching an existing joint profile is a matter of using the correct tool. In this example, a grapevine tool is chosen for.

Patching cracks in bricks

When a crevice runs through a brick, many people recall the solution is replacement. In that location are 2 problems with that, the first existence finding a replacement brick. Even if a brick with the aforementioned blueprint were available, the existing ones have weathered, and so a color match would be unlikely. The 2nd trouble is that removing an unabridged brick is invasive; particularly on an older wall, i brick tin can lead to another and and then to another. Instead, I fill croaky bricks with mortar dyed to lucifer.

To make staining the mortar joints less likely, I wait until the day after repairing the joints to fill up any cracks in the
bricks. It's difficult to get an exact color friction match. There are often several shades and colors of bricks in the aforementioned wall, and in many cases, individual bricks are mottled with different shades and colors. Even if I don't match the color of each brick perfectly, using a color that matches some bricks in the wall goes a long way toward making the crack disappear and maintaining the bond pattern on the wall.