Copyright Goodheart-Willcox Co., Inc. Chapter 12 Laying Brick 245 concern is that all of the ties are in place, remain oper- ative, and are firmly embedded in and bonded to the mortar. In order to achieve this, the two wythes must be laid with completely filled bed joints and the ties must be in the correct position so later disturbance of the wall assembly is unnecessary. Wall ties do their job if properly embedded. Ties should be 3/16″ in diameter or #9 gauge wire and placed in every 4 1/2 sq ft of wall space when the cavity is no more than 4″. The most common type of wall tie for brick masonry construction is the Z tie. Rectangular and U-shaped ties may also be used when the backup units are hollow masonry units with cells laid vertically. See Figure 12-59. The most important factors affecting performance of wall ties are as follows: ■ ■ Corrosion resistance. ■ ■ Placement of ties at proper spacing. Twice as many ties should be used if they have drips. Crimping the ties reduces the strength. ■ ■ Full bedding of the bed joint and placing the wall tie in the mortar 5/8″ from either edge of the masonry unit. Prefabricated horizontal joint reinforcement may be used to tie the interior and exterior wythes, but truss type joint reinforcement should not be used to tie the wythes of a brick and block cavity wall together. Rather, ladder type reinforcement, which allows for the in-plane movement between the wythes, is recom- mended. Horizontal joint reinforcement is generally not required in brick masonry walls because they are not subject to shrinkage stresses. Storage of Materials The proper storage of materials at the construction site may have an important influence on their future performance. Masonry units should not be allowed to become wet from rain or snow or to be contami- nated by salts or other chemicals that may contribute to efflorescence and staining. ■ ■ Masonry units. Masonry units should be stored off the ground to avoid contamination by dirt and groundwater that may contain soluble salts. Also, masonry units should be kept dry from rain or snow. ■ ■ Cementitious materials. Cementitious materials should be protected from the elements and stored off the ground. ■ ■ Sand. Sand for mortar should be placed on high ground or off the ground to prevent contamination. A protective cover is advisable in cold weather to prevent saturation and freezing. Air space Joint reinforcement Goodheart-Willcox Publisher Figure 12-59. Rectangular ties and joint reinforcement used in cavity wall construction. Workplace Skills Professional Behavior No matter what career or skill area you select in the masonry field, there are certain professional behaviors that a new or seasoned employee should possess or strive to develop. A few tips to keep in mind when hired by an employer: ■ ■ Show respect for your employer and team members you work with during the day. Everyone will need to work together in a cohesive manner from the laborer to the superintendent to accomplish the task at hand or project being constructed. ■ ■ Arrive earlier to the job, at least 15 minutes before the schedule time when work begins. Use the extra time to prepare for the day. For example, grab your masonry tool bag from your pick-up and move to the location on the worksite where you will begin the day. Review yesterday’s work to make plans for how you will begin working today. ■ ■ Continue to work throughout the day without being told to stay busy. If the project you were performing has been completed, contact your supervisor to be assigned a new task. ■ ■ When the work day is coming to an end, continue to work and stay busy. The employer is paying for a full day’s work. Do not start thinking about what you will be doing after work. There is plenty of time to do this after leaving the jobsite. These tips will help you advance in your masonry career. They will also help you shine as a valuable employee.