A: When no joint reinforcing is used, National Concrete Masonry Association (NCMA) TEK 53, "Design of Concrete Masonry for Crack Control," recommends spacing control joints in straight wall sections without openings no farther apart than twice the height of the wall, 40 feet maximum.
The National Concrete Masonry Association (NCMA TEK 10-2C) recommends that control joints be spaced at 25 feet or 1.5 times the height of the wall, whichever is less.
Concrete control joints should be no less than ¼ of the total thickness of the slab (1” deep for a 4” thick pour) and placed no less than 2-3 times (in feet) the thickness (in inches) of the slab (8-12 feet apart for a 4” thick pour).
Ties should be spaced every 12” or 16” vertically and every 16” or 24” horizontally depending on stud spacing. This supports most codes which require one wall tie for every 2.67 SF of wall area.
The way to prevent the cracks is to make the length of the walls meeting at the corner short by placing control joints near the corner. The normal “rule of thumb” is to place either one joint at the corner or to place two joints spaced no more than 20 to 25 ft. (6 - 8m) apart around the corner.
As a general rule, the spacing of vertical movement joints in clay brickwork should be between 10m and 12m apart. In calcium silicate brickwork the spacing should be typically between 7.5m and 9m apart. In concrete brickwork the distances are between 6m and 9m.
Movement joints in internal walls are not normally necessary for single dwellings unless the walls are straight and unbroken and over 6m long, in which case the block manufacturer's recommendations should be adopted. This may include the use of bed joint reinforcement in the courses above and below window openings.
They are usually placed 16 inches apart on all walls. It can vary in older homes, but rarely would you find studs more than 24 inches apart.
Masonry to masonry
Nine-gage wire ties are spaced one anchor every 2.67 square feet, and 3/16-inch wire ties are spaced one anchor every 4.5 square feet. The maximum spacing is 36 inches horizontally and 24 inches vertically.
The maximum horizontal spacing is 900mm and the maximum vertical spacing is 450mm, although this may be varied if required by the Building Regulations. The ties should be evenly distributed over the wall area, in a staggered pattern, except around openings.
The location of the control joints is based on where and why brickwork cracks. The joints create brick panels which are independent of each other. For vertical control joints, there are a number of conditions that need to be considered. First, vertical cracks may occur at the corners.
Control joints shall be placed at locations where the slab width or length changes. Exception: Control joints may be omitted when the slab is reinforced in accordance with Table R506.
Contraction joints are chiefly defined by their spacing and their method of load transfer. As per I.R.C, the maximum spacing of these joints is 4.5 m in plain cement concrete slabs.
Vertical masonry movement joints should be located on both sides of outside wall corners so that the dis- tance between them does not exceed the appropriate spacing between movement joints for that specific project (Figure 3A).
4) recommends a contraction joint spacing of 30 times the wall thickness, or 20 feet for an 8-inch- thick wall (30 8 = 240 inches = 20 feet). Some designers recommend re- ducing joint spacings by about 20% in walls with frequent openings, such as doors and windows.
For other thin brick installation methods, incorporate movement joints at regular spacings. Spacing. The distance between movement joints should not be more than 18 ft (5.5 m) either vertically or horizontally. Areas between movement joints should not exceed 144 sq ft (13.4 m²).
A: When no joint reinforcing is used, National Concrete Masonry Association (NCMA) TEK 53, "Design of Concrete Masonry for Crack Control," recommends spacing control joints in straight wall sections without openings no farther apart than twice the height of the wall, 40 feet maximum.
As a general rule, the anchor & fastener industry has established the following minimum spacing standards: Ten (10) anchor diameters between anchors, five (5) anchor diameters from the edge.
The maximum recommended control joint spacing for walls and ceilings without perimeter relief is 30 feet. With perimeter relief the maximum recommended control joint spacing is 50 feet.
Beaded Joint: Similar to the squeezed joint, the beaded joint is not typically recommended for exterior building walls due to its exposed ledge.
Research has shown exterior framed walls can be adequately supported by 2x6 studs spaced 24-inches on-center. This wider spacing reduces the number of studs in the wall, thus reducing thermal resistance and increase the amount of space available for insulation.
Vertical expansion joint spacing should not exceed 25 ft (7.6 m) in brickwork without openings and 20 ft (6.1 m) for brickwork with multiple openings. The actual location of vertical expansion joints in a structure is dependent upon the configuration of the structure, as well as the expected amount of movement.
Whether it be brick, stone, or another type of masonry unit, masonry is not meant to be a rigid impermeable surface, and historically we understood that it needed to breathe as well as expand and contract with changes in temperature/moisture levels.
In building materials, a control joint is used to control cracking while an expansion joint is designed to handle structural movement.