PART 1: GENERAL
2.01 Concrete Masonry Units
I. Heritage Collection Designer Concrete Brick:
ASTM C 90
a. Heritage Collection Designer Concrete Brick as manufactured and distributed by County Materials Corporation.
b. Integrally Pigmented Load-bearing Units.
i. Unit dimensions as required by building plans.
ii. Normal weight.
iii. Hollow block, as indicated, with a net cross sectional strength of 2500 psi
iv. Integral synthetic iron oxide pigments.
v. Integral polymer emulsion water repellent.
vi. Colors: Heritage Collection I, Color____________________________
vii. Colors: Heritage Collection II, Color____________________________
viii. Substitutions: Not permitted.
II. Heritage Collection Designer Concrete Brick:
ASTM C 55.
a. Heritage Collection Designer Concrete Brick as manufactured and distributed by County Materials Corporation.
b. Integrally Pigmented Non-loadbearing Units.
i. Grade S, cored, normal weight.
ii. Unit dimensions as required by building plans.
iii. Cored brick, as indicated, with a net cross sectional strength of 2500 psi
iv. Efflorescence: Not effloresced, in accordance ASTM C67-02
v. Integral synthetic iron oxide pigments.
vi. Integral polymer emulsion water repellent.
vii. Colors: Heritage Collection I, Color______________________________
viii. Colors: Heritage Collection II, Color______________________________
ix. Substitutions: Not permitted
Submittal:
Submit full size color sample(s) of each color specified or selected from manufacturer's color palette. Submit product literature, test reports, and product certifications.
Quality Assurance:
Decorative (veneer/structural) concrete masonry units shall be Heritage Collection Designer Concrete Brick as manufactured by County Materials Corporation. All units shall conform to ASTM C 90 Loadbearing Concrete Masonry Units and ASTM C 55 Concrete Brick. Units shall have a [specify face option] (smooth, striated, rough estate or split) face as designated on the drawings or in the specifications.
Field Constructed Mock-ups or Sample Panels:
Construct a separate (not part of the actual building) sample wall panel not less than 4' by 4' with units in the pattern, color and shape as indicated in drawings and specifications. Cleaning agents and methods shall be performed prior to approval of the sample panel. Walls erected without a sample panel will be considered approved "as is".
Delivery, Storage and Handling:
Heritage Collection Designer Concrete Brick shall be delivered to the job site on pallets and stacked only one pallet high on level ground. Delivered pallets shall be protected from inclement weather with a waterproof covering. Units shall be handled carefully to avoid breakage and damage.
Design Practices and Installation:
Careful consideration should be given to the placement of control joints and the use of horizontal joint reinforcement, brick wall ties, weep holes and water resistant sealants. It is expected that Heritage Collection Designer Concrete Brick units will be laid using the best concrete masonry construction practices. For maximum construction efficiency and economy, concrete masonry walls should be designed and constructed with modular coordination in mind. Standard dimensions for Heritage Collection Designer Concrete Brick are equal to the nominal dimensions, less the thickness of one mortar joint (3/8"). Heritage Collection Designer Concrete Brick should not be wetted prior to placement.
Control Joints:
Control joints are one method used to relieve horizontal tensile stresses due to shrinkage of concrete masonry units, mortar, and when used, grout. They are essentially vertical separations built into the wall at locations where stress concentrations may occur. These joints reduce restraint and permit longitudinal movement. Concrete brick requires vertical control joints to accommodate panel contraction.
Control Joint Placement:
Control joints should be located where volume changes in the masonry due to drying shrinkage, carbonation, or temperature changes are likely to create tension in the masonry that will exceed it's capacity. The following are suggested methods to provide guidance in locating control joints. (see Figure 1)
- At changes in wall height
- At changes in wall thickness, such as at pipe and duct chases and pilasters
- At (above) movement joints in foundations and floors
- At (below) movement joints in roofs and floors that bear on the wall
- Near one or both sides of door and window openings, (generally, a control joint is placed at one side of an opening less than 6 ft wide and at both jambs of openings over 6 ft wide). Control joints can be away from the opening if adequate tensile reinforcement is placed above, below and beside wall openings. Adjacent to corners of walls or intersections within a distance equal to half the control joint spacing requirement for that wall.
For more detailed control joint spacing, see NCMA Tek Note 10-2B and 10-4.
Empirical Crack Control:
For walls without openings or other points of stress concentration, control joints are used to effectively divide a wall into a series of isolated panels. Table 1 lists recommended maximum spacing of these control joints based on empirical criteria. For walls containing masonry parapets, consider the parapet as part of the masonry wall below if it is connected by masonry materials such as a bond beam unit when determining the length to height ratio.
For more detailed control joint spacing, see NCMA Tek Note 10-2B.
FIGURE 1: TYPICAL CONTROL JOINT LOCATIONS
TABLE 1
Recommended Control Joint Spacing for Above Grade Exposed Concrete Masonry Walls*
DISTANCE BETWEEN JOINTS SHOULD NOT EXCEED THE LESSER OF:
Length to height ratio 1-1/2 or 20 (6.10) ft (m)
Notes:
- Table values are based on the use of horizontal reinforcement having an equivalent area of not less than 0.025 in.2/ft (52.9 mm2/m) of height to keep unplanned cracks closed.
- Criteria apply to all concrete masonry units.
- This criteria is based on experience over a wide geographical area. Control joint spacing should be adjusted up or down where local experience justifies but no farther than 20 ft (6.10 m).
The control joint spacings of Table 1 have been developed based on the use of horizontal reinforcement to keep unplanned cracks closed as indicated in footnote.
Horizontal Joint Reinforcement:
Continuous, 4" joint reinforcement is required 16" on center vertically in all veneer applications and in the exterior wythe of composite wall construction. Nonstructural, horizontal, joint reinforcement, should not be continuous through a control joint, since this will restrict the horizontal movement. However, structural reinforcement, such as bond beam reinforcement at floor and roof diaphragms that resists diaphragm cord tension, must be continuous through the control joint, but provisions should be allowed for longitudinal movement.
Weep Holes:
To properly drain water collected on any flashing or horizontal surface, weep holes must be provided immediately above the flashing or horizontal suface at all locations, following standard industry practices. Weep holes should be at least 1/4 inch in diameter, and should be spaced no further apart than 32 inch. o.c. horizontally. When using wick type material in the weep hole, the spacing should be reduced to a maximum of 16 inch o.c. (see Figure 2)
FIGURE 2: WEEP HOLES
Veneer Anchors:
County Materials Corporation recommends using an anchor that allows for vertical & horizontal movement. Examples are DW-10 manufactured by Hohman Barnard or Type III veneer anchor w/triangular tie manufactured by Wire Bond. (see Figure 3)
FIGURE 3: ANCHORS
Flashing:
The primary role of flashing is to intercept the flow of moisture through masonry and direct it to the exterior of the structure. Flashing is recommended for all locations where moisture may potentially penetrate into a wall and where the free drainage of water is blocked. Some of these critical locations include the top of walls and parapets, at all horizontal obstructions such as over openings, beneath sills, above shelf angles, and at the base of walls. Flashing may also be utilized in walls at ground level to serve as a moisture retarder to reduce the amount of water wicked up into the masonry above grade. Weep holes and vents also reduce the moisture content of masonry walls.
Project/Site Conditions:
During construction of exposed concrete masonry, minimize mortar and grout smears on the face of the units. Mortar droppings which adhere to the exposed face of the units can be removed with a trowel or chisel after being allowed to harden. Any remaining mortar can then be removed with a stiff fiber brush. The base of the wall should be protected from mud splashing and mortar droppings by spreading plastic sheets four feet on the ground and three feet up the wall. Covering the tops of unfinished walls at the end of the workday prevents rain and outside elements from entering the wall and thus reduces the chance of efflorescence forming on the wall. Covers should be draped at least two feet down each side of the wall and a method provided to hold them in place.
Mortar and Mortar Joints:
Use regular gray or a complementary color to match the Heritage Collection Concrete Brick. Concave or V-shaped tooling of joints, when the mortar is thumbprint hard, improves moisture resistance by compacting the mortar against the masonry unit to seal the joint. Raked, flush, struck, beaded, or extruded joints are not recommended as they do not compact the mortar and/or create ledges that intercept water running down the face of the wall. Head and bed joints should be the full thickness of the face shells for optimum water tightness.
Cleaning:
Heritage Collection Concrete Brick can be cleaned using traditional masonry cleaning methods, such as mild masonry detergents/cleaners and power-washing systems properly applied. Strong acids, acid washes or chemicals with a strong acid reaction should not be used, since they may reduce the water repelling properties of treated masonry and etch the surface, distorting the color. Keep the masonry wall clean as the construction progresses and use a brush and water after the mortar has hardened.
Water Repellents:
Heritage Collection Concrete Brick are manufactured with Rheopel integral water repellent. Rheopel resists water penetration associated with wicking by increasing the friction on water molecules. Rheopel also reduces the potential for efflorescence and staining from environmental pollutants, and enhances the color and texture of a wall. Rheopel water repellent mortar admixture should be used in the mortar to ensure compatibility and enhance bond.
Extreme Weather Construction:
Temperatures between 40 and 90°F (4.4 and 32.2°C) are considered "normal" temperatures for masonry construction and therefore do not require special procedures or protection protocols. When ambient temperatures fall below 40°F (4.4°C), the Specification for Masonry Structures requires consideration of special construction procedures. Similarly when the minimum daily temperature for grouted masonry or the mean temperature for ungrouted masonry falls below 40°F (4.4°C) during the first 48 or 24 hours after construction respectively, special protection considerations are required.
Rain and Masonry Construction:
The presence of rain, or the likelihood of rain, should receive special consideration during masonry construction. Unless protected, masonry construction should not continue during heavy rains, as partially set or plastic mortar is susceptible to washout, which could result in reduced strength or staining of the wall. However, after approximately 8 to 24 hours of curing (depending upon environmental conditions), mortar washout is no longer of concern. When rain is likely, all construction materials should be covered. Newly constructed masonry should be protected from rain by draping a weather-resistant covering over the assemblage. The cover should be secured in place and extend over all mortar that is susceptible to washout.
(References: National Concrete Masonry Association TEKs)
PART 2: PRODUCTS
Manufacturer:
Architectural concrete masonry units shall be Heritage Collection Designer Concrete Brick as manufactured by County Materials Corporation (800-289-2569). Units shall meet or exceed the requirements of:
- ASTM C 90 Loadbearing Concrete Masonry Units
- ASTM C 55 Concrete Brick
- Normal weight 140 l bs./cu. ft.
Colors:
Colors shall be selected from manufacturer's colors:
- Natural gray
- Series I or Series II integral blended colors
- All County Materials standard colors
Compressive strengths:
Average net area: 4000 psi
Absorption:
Maximum water absorption (24 hr. submersion): 6.8%
County Materials Corporation
Corporate Office
205 North Street, P.O. Box 100
Marathon, WI 54448-0100
800-289-2569
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