When you’re a builder, architect or general contractor, it’s essential to work with a masonry business you trust.
That’s because there’s a lot more to masonry than bricks, stone, mortar and grout. From the outside, nearly anyone in the field can make a structure look good. But, the most important components on masonry are contained within the wall, such as the flashing systems, details in the CMU masonry, the reinforcing and the spacing of reinforcing. All the components behind the facade are what ensure the brickwork is structurally sound, long lasting and waterproof.
Following are 5 shortcuts on the masonry job that speed up the work or lower material costs but can have disastrous results in the long run.
Perfection for inspection
Commercial building sites have regularly scheduled inspections, and contractors typically know when to expect an inspector. On these days, every mason in business will be sure to space out the reinforcing at the required distances. However, other days on the job, it’s a lot easier and faster to skip the vertical reinforcing steel in the masonry wall.
For example, when you’re reinforcing CMU, the typical low lift method is to add reinforcing steel every 4-5 feet with the correct rebar lap distance. You have to stop and place vertical reinforcing bars in the cells and then perform the grouting of these cells. Grouting this smaller section can be more time consuming, so a lot of people will run 8-10 feet before adding reinforcing and grouting. The problem arises when you then grout at that higher lift. With higher lift grouting, air pockets may become trapped during the pour if relief holes are not created. If the grout traps air, this creates a void that compromises the structural integrity of the wall.
In high lift grouting, the mason needs to cut air release holes, typically at the bottom and halfway points of the lift. However, it saves the mason a lot of time to skip this step in reinforcing the wall. The only way to monitor this would be with more frequent, surprise inspections and performing an x-ray scan of the wall after completion. This is why it’s essential to work with a masonry company you trust.
Let’s talk flashing
In brick and stone veneer some masons will cut corners while installing the flashing systems. The flashing system ensures that any moisture that gets into the wall will exit the wall at the base or over openings. Flashing varies building by building. For example, 40-mil. self-adhesive flashing runs up a masonry wall and then down under the first course of masonry, or masonry at grade, and out the wall. Because this kind of flashing gets brittle from UV rays and exposure to the elements, the most common way to alleviate this is by installing a stainless steel drip edge over the top of the exposed self adhesive flashing. The steel keeps the flashing from being exposed to sunlight. The first place to cut a corner in flashing installation is by leaving off this steel drip edge, especially because some architects don’t include it in the drawings. Our standard practice at Chicago Masonry Construction is to always install this steel edge whether it’s called for or not, unless directly requested at the architects direction.
When the flashing runs up the back of the wall, the adhesive wears out over time. A termination bar screwed into top of flashing ensures that even if the adhesive fails, it remains attached to the wall. Across the top of the termination bar, a bead of mastic is installed to seal the top. This is not required but is recommended, so it’s typically our standard practice at Chicago Masonry.
Cleanliness is more than a good habit in masonry
Although no one sees what’s behind a wall, a messy mortar application there can affect the integrity of a structure. This is because globs of mortar can get stuck in the wrong spot in the wall cavity, affecting water drainage. At the bottom of the wall, weeps draw water down the flashing system and out the wall. If bricklayers are messy, these globs can fall behind the wall and land where a weep is, rendering the weep ineffective. It’s important that bricklayers take extra care that this doesn’t happen by using a spacer, such as rigid insulation, to prevent any mortar from falling into the wall cavity. This is a piece that a mason can raise as he builds the wall, ensuring he keeps the cavity clean. The other option would be a product such as Mortar Trap© installed in the wall cavity directly above the flashing system to prevent the mortar globs from reaching the weeps. Unfortunately, a product such as this is not specified on all projects.
Wall ties are an essential part of the masonry veneer system, keeping a structure safe and stable. There are more than 20 different standard types of these wire or sheet metal devices that are used to connect two or more masonry wythes or veneers to a structural backing system. Each type is situational–all with different purpose and price–but it is better to avoid any wall tie that is a one piece with a single screw into substrate. This gives the veneer the opportunity to move slightly with changing conditions. A two-piece wall tie consisting of an anchor plate secured with two screws and an adjustable veneer tie hooking into the anchor plate is the recommended method. In earthquake zones or in areas with extreme temperature fluctuation, why not have peace of mind that your wall ties are moving with the wall and not causing a crack?
Better mortar for an ancient trade
Masonry may be one of the world’s most ancient trades, but the mortar of the last dozen years or so has shown significant improvement. Gone are the days of a dump truck tossing a huge pile of sand at the work site for masons to mix a bucket of this with a bucket of that. Field mixing of portland, lime and sand with water was messy and inexact. And if the pile of sand froze in the winter, the only way to continue making mortar was by melting it with a propane torch.
Today, more masons use ready mix mortar with a silo delivery system, which has a slightly higher cost but alleviates a lot of headache. The mortar (sand pile) doesn’t consume as much space, and it’s a cleaner and more accurate method. Pre-packaged ready mix mortar mortar is available in a wide variety of type for multiple applications. The standard “S” and “N” types are obviously available, but options such as polymodified adhesive mortars, water repellent mortar, and a wide variety of colored mortars are also available.
When it comes to masonry work, it’s what’s on the inside that makes a difference. This is true for the building structure, and it’s true for the business as well.
Jason Josvoi is a senior estimator and project manager at Chicago Masonry Construction and is certified by Mason Contractors Association of America. Chicago Masonry Construction is a full-service commercial masonry, EIFS/stucco and caulking contractor serving architects, construction managers, condominium associations, developers, general contractors, homeowners and both private and public institutions since 1986.