by Aaron Miller, Certified Master Inspector®
The common brick may be the best exterior cladding material ever devised. After all, what other cladding offers a 100-year warranty, is made from common green materials, is recyclable, requires low maintenance, provides excellent fire performance, and more?
Like any other building material, bricks will perform as intended only if installed as required by industry standards. I have found a considerable number of masonry installation defects on every house I’ve inspected. To follow are the most common ones.
Handling of Bricks During Placement
Prior to placement in a wall, bricks should never be stored in direct contact with the ground. They should always be stacked on planks. In my experience, however, I have rarely seen this done properly. OSHA also has its own list of requirements regarding the stacking and storage of bricks that does apply to residential construction.
For a cavity wall to function properly, such as those found in brick veneer construction, water that collects on the underlying weather-resistant barrier (e.g., sheathing and flashing) must be able to evaporate and drain through weep holes to the exterior of the building. If the weep holes do not function properly, water collecting in the cavity can infiltrate to the building’s interior. For proper drainage, cavity walls must be constructed to keep the cavity clear of mortar droppings, detailed correctly, and prevent weep-hole blockage.
There are several ways to satisfy the weep hole requirement in the IRC, such as wicks, weep vents, etc. Code-compliant weep holes in Texas, for example, typically consist of omitting the head joint between the bricks at 33-inch intervals above any flashing. This includes the sill flashing above all lintel-supported openings, including doors, windows, knee walls, etc. Even when these openings are provided, poor workmanship may result in the blockage of weep holes when mortar is dropped into the wall cavity during the installation process. One method to prevent this is the installation of products that help keep the weep holes clear, such as MortarNet®.
In new construction, it is easy to observe that wall and brick installation variations (as well as the installation of plumbing, gas piping, etc.) in the air space do not always provide the 1-inch clearance as required by the IRC. This is considered a defect.
In both existing and new construction, the addition of weep holes is strongly recommended. The IRC requires only a 3/16-inch hole to be drilled in all locations requiring weep holes, thus deflating the argument that weep holes are just too difficult to add post-construction.
Homeowners often attempt to prevent mice and insects from entering weep holes by stuffing them with steel wool. This is a bad idea. The steel wool rusts and serves to fully block the weep-hole openings. Better materials are available that serve this purpose, such as stainless steel wool, bronze wool, copper mesh, plastic substitutes, and retrofitted screen devices.
With one rarely-invoked exception, the 1-inch air space between the back of the brick veneer and the face of the sheathing must remain clear in order to function as a ventilation cavity. Mortar dropped by masons into the cavity during the brick installation process can limit the air flow in this air space. Additionally, connecting the brick veneer to the sheathing creates a thermal bridge, which is not allowed by the IECC. Some sheathing manufacturers (such as Huber’s ZipSystem®) strictly prohibit bridging the gap between their sheathing and the brick veneer, as this would void their warranties. The air space is almost never ascertainable on exiting construction, so this defect is usually observable only in new construction.
Brick veneer undergoes long-term expansion over the life of the brick, though most of this expansion takes place during the first few years. It is also subject to short-term expansion and contraction due to exposure to the sun. Most bricks are manufactured so that, given an annual temperature differential of 100° F., an expansion of approximately 5/8-inch will be experienced in a 100-foot-long wall.
Industry standards require the installation of expansion joints at 25 linear feet on center in walls with no openings, and 20 linear feet on center for walls with openings (such as windows and doors) to prevent damage to the veneer during expansion and contraction.
Expansion joints should first be filled with a closed cell backer rod and then sealed with an approved sealant. Under no circumstances must expansion joints be filled with mortar or wood. Positioning expansion joints near window or door openings can cause structural problems.
Brick Wall Ties
The use of wall ties dates back to the 1850s. The standard ties used today consist of corrugated galvanized steel strips approximately 6-9/16 x 7/8-inch. One end of the tie is nailed to the sheathing over framing (which must be attached to a stud), and the other is extended into the mortar joint.
Typically, wall ties perform three to four primary functions between the brick veneer and its backing:
Brick ties are not visible during inspections on existing homes, but defects in them or their installation can often be ascertained through close observation. Loose walls that move when pushed by hand are indicative of inadequate, missing, or failed (rusted-out) ties. It is possible to repair such walls in situ using devices such as the Simpson Heli-Tie®.
On inspections of new construction, it is important to note the spacing, fastening and alignment of the ties to ensure their proper performance.
Sloping (Slanting or Canting) Horizontal Surfaces
All horizontal brick surfaces must be sloped (slanted or canted) in order to promote drainage. Window sills are the major culprit with houses. The primary function of a sill is to channel water away from the building. The sill cannot be level or sloped back toward the building if it is to perform as intended. Additionally, the 15-degree slope requirement of the Brick Industry Association’s Technical Note 36 is rarely met.
Common mortar types for brick veneer include Types N, S, and M. Type N is almost exclusively used for above-grade walls, unless Type S is specified. Type M is used for below-grade work, such as for retaining walls. Mortar failure is often due to the use of the wrong type of mortar for the application.
Many styles of tooled joints are used in brick veneer mortar. The three most common are the V-joint, concave, and weather joints. These tend to provide the most weather resistance over time. Other types of joints are often problematic.
This category of defects is the most common and egregious. Flashing is the material (usually of metal or plastic) that makes the transition between the brick veneer and dissimilar types of cladding present on the building exterior, such as siding, trim, other types of masonry, roof coverings, etc.
With many production builders’ preference of using sub-contractors, the responsibility for the installation of flashing has fallen into a grey area. Many brick masons do not think it is their job, and neither do many exterior trim carpenters or roofers. This situation is further exacerbated by the desire for speed of construction. And the old-time method of brazing or soldering the joints in metal flashing is out of fashion due to a lack of skilled workers. Thus, the flashing usually does not get installed properly, if it gets installed at all.
Joints in flashings constructed today commonly rely on sealants in order to prevent moisture intrusion. While flashings are durable materials that can last for decades, sealants have short life spans and must be renewed at regular intervals and at great expense.
Another issue is the common use of ICC-approved, self-adhered flashings behind brick veneer at window and door headers and other wall openings. This practice has effectively done away with the IRC-required through-wall flashings (at least in the minds of many builders and municipal inspectors).
The top flashing issues I encounter are:
Missing or non-continuous sill flashing at the brick ledge can lead to many issues, such as moisture intrusion, and those ubiquitous cracks at the outside corners of slab-on-ground foundations known as truncated cone fractures.
The lack of end dams in all horizontal flashings can lead to lateral movement of water into the walls.
Proper knee wall flashing details are critical to prevent moisture intrusion.
Most inspectors have observed water stains on framing in attics adjacent to chimneys. Poor flashing is almost always the reason.
Lintels are L-shaped steel members that support openings in brick veneer walls. These are required over all openings where the brick veneer would otherwise be acting as a beam, which it cannot do.
The major problems typically observed include:
Lintels are required above even the smallest openings in brick veneer. Small windows, pet doors, gable vents, etc., are locations where they are typically missing.
The effects of under-sizing lintels can usually be seen above overhead door openings at garages, especially where there is a second story of brick veneer being supported above.
All lintels are required to be supported a minimum of 4 inches at each end, per the IRC.
Lintels are shipped from the factory with a red primer intended to prevent corrosion during shipping, handling and installation. This coating is not sufficient to withstand the elements once the lintel is installed in a brick wall because uncoated metal rusts. Rusting metal exfoliates, thus expanding and opening mortar joints. It’s typical to see that a painter has just blown a coat of latex paint on the rusted lintel without the proper preparation or primer.
Spalling is the exfoliation or sloughing away of the outer surface of brick due to water absorption and exposure to freeze-thaw cycles. It can also be due to mechanical defects, such as use of incorrect mortar type, sandblasting, improper cleaning, or the deterioration of the internal anchoring system.
Minor spalling is mostly a cosmetic issue. Replacement of a few bricks is an option if matching bricks are available. If not, repair with fast-setting repair mortar and a color-matching stain may do the trick. For widespread spalling, replacement of the brick veneer is the best option.
Efflorescence is a white, powdery deposit of water-soluble salts left on the surface of brick after the water evaporates. If not caused by underlying moisture intrusion issues, simple cleaning is usually sufficient to deal with this.
Exterior brick veneer walls should, ideally, not be painted. If painting is somehow required or desired, the type of paint used is critical. If it does not have the proper permeability rating (ability to breathe), it will serve to trap moisture in the bricks, as well as the air space behind the bricks.
Furthermore, it is somewhat illogical to paint bricks. Once even the proper paint is applied, one must then repaint the bricks on a regular basis, thus defeating the low- to no-maintenance advantage of using bricks in the first place. But as it is a matter of aesthetics, proper maintenance, including repainting as needed, will help the brickwork last longer and preserve their visual appeal.
Repairing brick veneer takes more skill than laying it new. Skilled masons are in short supply. Thus, most brick repairs that I see are substandard. From tuck-pointing to repairing distress cracks, and replacing single broken bricks, the lack of craftsmanship is often apparent.
When done by an amateur, tuck-pointing or re-pointing of mortar joints can result in water intrusion at the poorly-tooled joints. Brick crack repairs, such as following foundation repair attempts, should ideally be accompanied by through-wall reinforcement of the veneer on both sides of the cracks using a product like Simpson’s Heli-Tie®. Single bricks are often hard to replace because matching bricks cannot be found. In almost all cases, attempts to match new mortar to old are unsuccessful due to the shortage of skilled artisans.
There are some valid reasons and some approved methods for the cleaning of the surface of brick veneer. Most of them, however, are not adhered to in practice. The most common defects I see are the improper use of power washers, and improper use of acid washes. If performed by the unskilled, both methods of cleaning can result in the weakening or complete removal of the hardened outer brick surface produced by the original firing. The consequences can be soft bricks that are incapable of withstanding moisture intrusion and are subject to damage through spalling.
Cheaper substitutes for brick veneer are always popping up so that unscrupulous builders can eek out another penny for each house they build. One that is already causing problems is commonly referred to as stick-on brick, properly known as adhered masonry veneer. Another is concrete bricks.
Trivia and Facts About Brick Performance
The information in this article is limited to residential brick veneer applied over wood framing in the author’s service area (Dallas, Texas and the surrounding area). While installation techniques may vary in different parts of Texas and across the country, most of the issues cited are commonly found in the U.S. and elsewhere. This information is not intended to be the definitive treatise on brick veneer but, rather, an overview based on the author’s experience during more 40 years in the fields of residential construction and home inspection.
About the Author
Following six years in the U.S. Army, Aaron D. Miller began work as a general contractor in the residential building and remodeling industry in 1975, until becoming a full-time home inspector in 1997. A member of InterNACHI and a Certified Master Inspector®, Aaron is also a TREC-Licensed Inspector and Professional Instructor, a Master TPREIA Inspector, and an ICC-Certified Residential Inspector in five areas. He is a native of Dallas and has lived in the Dallas suburb of Garland for the past 15 years. A full list of his extensive professional credentials can be found on his website at www.texasinspector.com
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