Often we tell architects, contractors and our distributors that our glazed brick is installed generally “the same as regular face brick”. I would like to review some of the similarities and differences to be aware of when handling a glazed brick installation.
Glazed brick is generally installed in the same manner as face brick. Type N or S mortar is recommended for most installations following the guidelines in ASTM C-270. A 3/8″ joint size is typical with full head and bed joints (use a soft joint under the coping and shelf angles). Never use a sealer on the mortar joints.
Wall ties and expansion joints should be spaced in the same fashion as with face brick. Wall ties should be minimum 3/16″ dia. steel and placed at least every 24″ vertically and 36″ horizontally, or per local building codes. The current ACI530 states a minimum of one every 3-sq feet. Ties for veneer brick over steel stud back-up systems should be 2-piece adjustable, corrosion resistant spaced per every 1.67 sq. feet of wall area. Expansion joints should be located on each side of a corner at 4′ to 10′ from the corner. Use flexible anchors to connect to columns and beams.
Cavity wall construction is a basic BIA recommendation for all veneer brick construction. A minimum 2″ cavity wall works best for glazed brick walls. It is suggested that a vapor barrier be placed on the warm side of the interior wall to help control condensation. The glazed brick itself should be laid so that the coring is vertical. This allows gravity to drain any moisture through the wall to the flashing. Flashing should be placed at the foundation course, sills, steel lintels, and parapet walls under the coping material and at any design openings. Proper drainage is dependent on how easy water can escape from the walls. Weep holes or vents should be placed every 24″ on center (o.c.) at the foundation level and at every 32″ o.c. (staggered) at the lintels, sills, coping, etc.
A vented cavity drainage wall is the best system for a glazed brick veneer. Stagger vents placed in the head joints at 24″ o.c. at the top and bottom of any continuous expanse of glazed brick wall. This will help circulate the air within the cavity, drying the walls faster. The vents at the bottom of the wall sections take the place of weep holes as a way for water to escape from the cavity via the flashing. The rain screen wall system is a similar method to use with glazed brick walls. This method divides the walls into sections or compartments. Each compartment is still vented at the top and bottom using flashing. An air barrier over the interior wall within the cavity is also necessary to prevent airflow through the interior wythe. Besides allowing for air circulation, this method also equalizes the atmospheric pressure inside the cavity with the outside air pressure. Therefore, it does not draw moisture into the cavity wall through the mortar joints. For more information on vented walls read the BIA “Vented Wall” E & R Digest.
Weep holes/vents and flashing are critical to glazed brick walls, as the impervious finish does not permit the face of the brick to breathe. Make sure during construction that the cavity opening is kept clean to permit this system to work.
Regions of the country that have freeze/thaw cycles should not use glazed brick in places that have water being applied to or near the wall, such as planters, fountains and below grade applications. Designs that create areas that can pool water should also be avoided.
Some differences with glazed brick are in the handling of the material at the jobsite. Our material will arrive with the brick strapped and stretch wrapped to a wooden pallet. Do not double stack these pallets! Cover the glazed brick to keep it clean and dry prior to installation. When the brick is ready to use, leave them in the factory packaging. This means NO brick tongs and NO pitching the brick up to the scaffolding and NO stacking. Glazed brick should not be taken out of the factory packaging until the bricks are in the mason’s hand ready to be laid in the wall. This helps prevent chippage, as the units are fragile until installed in the wall.
Concave joints using a 1 ½” plastic jointer work best. Do not use metal tools on the glazed face. When cleaning off clumps of dried mortar, use wooden scrapers. The walls should be wiped down with a coarse rag (like burlap or a piece of carpet) 30-45 minutes after they are erected or when the joints are thumbprint hard. This regular maintenance will make the final clean-down go much faster. During the final clean-down, be sure to wet the wall with clean running water prior to applying any detergent. Do not use muriatic acid as it may etch or yellow the mortar joints. A final rinse with clean running water should be done immediately. If by chance there is still a milky looking film on the glazed brick, wash the area with a solution of vinegar and water, then rinse. This will remove the residue and leave a great looking wall!