The following tables indicate the approximate number of linear feet filled by one gallon or one 10.1 fluid ounce cartridge.
TABLE 2 - JOINT WIDTH AND SEALANT DEPTH
Sealant Depth At Midpoint
APPROX. LINEAR FEET PER GALLON Joint Width
APPROX. LINEAR FEET PER CARTRIDGE Joint Width
In deep joints, the sealant depth should be controlled by the use of backer rod. Other caulks should not be used as fillers.Where depth of joint will prevent use of joint backing, an adhesive backed polyethylene tape must be installed to prevent three sided adhesion. Backer Rod is installed by compressing and rolling it into joint channel without stretching lengthwise.The rod must conform to the manufacturer’s recommendations as to size in relationship to joint width. Do not puncture during installation when using closed cell backer rod, and backing must be dry at time of sealant application. Figure 2 illustrates the use of a bond breaker to prevent three- sided adhesion.
APPROX. LINEAR FEET PER SAUSAGE Joint Width
PRINCIPLES OF JOINT DESIGN
A variety of factors are considered when designing the joint width and depth.The main areas of concern are maximum expansion, surface materials and their expected thermal change. When possible, CRL M66 Modified Polyurethane Construction Sealant should be applied when the joint is at its median opening, so as to obtain the greatest efficiency with joint movement.The dimensions of the joint must be established according to expected movement, number and location of joints.The design should be such that movement on any joint should not exceed ±25% maximum.This joint size can be calculated by determining the expected movement within the joint between the high and low temperature extremes and multiplying the change by a factor of four. For example, it is determined the joint will open and close 1/4" between temperature extremes, it follows, 4”x1/4"=1".The example joint should be a minimum of 1" wide.The depth of the sealant is also a very important consideration.The standard rule of thumb is that the depth should be half the width of the joint, with a maximum depth of 1/2" and a minimum of 1/4". See Figure 1 and Table 2 for these illustrations.
All surfaces where sealant is going to be applied must be dry, clean, free of loose particles, oil, grease, asphalt, tar, wax, rust, waterproofing coatings, mold release agents, and membrane materials, etc.
MASONRY: Concrete, stone and other masonry must be cleaned with wire brushing, grinding, or sandblasting. A sound surface free of contamination must be achieved before sealant application.
METAL: Metal finishes should be tested for adhesion on all new construction. Scale, rust, oils, grease, oxide, and protective lacquer coatings must be removed prior to sealant application.When using solvents on job sites all
P.A. recommendations for handling and safety must be followed. Any chemical residue or film must be removed prior to sealant application. Reference S.W.I. and NGA manuals for standard industry cleaning procedures.
PRIMING M66 is typically applied without the need for any primer. Excellent adhesion to most common building materials, including Kynar™ coated metals.
C.R. LAURENCE CO., INC. • CORPORATE HEADQUARTERS: POST OFFICE BOX 58923, LOS ANGELES, CA 90058-0923
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