Figure 5-17.—Grid system components.material requirements. Figure 5-17 shows the majorcomponents of a steel and aluminum ceiling grid systemused for the 2- by 2-foot or 2- by 4-foot grid patternsshown in figure 5-18.Pattern LayoutThe layout of a grid pattern and the materialrequirements are based on the ceiling measurements andthe length and width of the room at the new ceilingheight. If the ceiling length or width is not divisible by2 (that is, 2 feet), increase those dimensions to the nexthigher dimension divisible by 2. For example, if aceiling measures 13 feet 7 inches by 10 feet 4 inches,the dimensions should be increased to 14 by 12 feet formaterial and layout purposes. Next, draw a layout ongraph paper. Make sure the main tees run perpendicularto the joists. Position the main tees on your drawing sothe border panels at room edges are equal and as largeas possible. Try several layouts to see which looks bestwith the main tees. Draw in cross tees so the borderpanels at the room ends are equal and as large aspossible. Try several combinations to determine theFigure 5-18.—Grid layout for main tees.best. For 2- by 4-foot patterns, space cross tees 4 feetapart. For 2- by 2-foot patterns, space cross tees 2 feetapart. For smaller areas, the 2- by 2-foot pattern isrecommendedMaterial RequirementsAs indicated in figure 5-17, wall angles and maintees come in 12-foot pieces. Using the perimeter of aroom at suspended ceiling height, you cart determine thenumber of pieces of wall angle by dividing the perimeterby 12 and adding 1 additional piece for any fraction.Determine the number of 12-foot main tees and 2-footor 4-foot cross tees by counting them on the grid pattern5-16