STANDARD SPECIFICATION OF CAST STONE
A. This specification covers all labor, materials and services incidental to and including the furnishing and setting of all Cast Stone as indicated on the drawings and specified herein.
B. The Manufacturer shall be responsible for all labor, materials, equipment and services necessary for and incidental to providing all Cast Stone covered by this specification.
C. The Setting Contractor shall unload, receipt for, store and set all Cast Stone covered by this specification and shall provide and install all anchors for same.
II. QUALIFICATION OF MANUFACTURER
A. The Manufacturer shall have a minimum of ten years continuous operation, having experience, adequate facilities and capacity to furnish the quality, sizes and quantity of Cast Stone required without delaying the progress of the work, and whose products have been previously used and exposed to the weather with satisfactory results.
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A. Scale and/or full size detail drawings will be furnished where necessary by the Architect, and they shall be accurately followed in the execution of this work.
B. The Cast Stone Manufacturer shall prepare and submit for approval, complete properly marked setting drawings, showing details and sizes of stones; arrangement of joints; bonding; inserts; joints; connections to adjoining walls or materials; reinforcing; and method of installation and anchoring.
C. Unless otherwise specified, shop drawings shall provide the following:
1. Provide suitable wash on all exterior sills, coping, projecting courses and pieces with exposed top surfaces.
2. Window sills shall have raised fillets at the back.
3. All projecting pieces and soffit stones shall have drips under the outer edge.
4. The shop drawings shall show the setting mark of each stone and its location on the structure. The stone when delivered shall bear the same corresponding setting mark on an unexposed surface.
D. The Manufacturer shall submit the shop drawings to the General Contractor. The General Contractor shall verify all dimensions and coordinate the drawings with field conditions. The General Contractor shall submit shop drawings to the Architect for approval.
E. The shop and setting drawings shall be approved by the Architect and General Contractor before the Manufacturer shall be required to proceed with the work.
IV. MODELS AND MOULDS
A. Should models of ornaments be required, all models shall be prepared by skilled craftsmen in a correct and artistic manner in strict accordance with the spirit and intent of the approved drawings. Models shall be approved by the Architect before any work is executed therefrom.
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A. Cement - Portland Type I or Type III white and/or gray meeting ASTM C 150.
B. Fine aggregate - carefully graded and washed natural sands, or manufactured granite, quartz or limestone sands meeting ASTM C 33 except that gradation may vary to achieve desired finish and texture.
C. Coarse aggregate - carefully graded and washed natural gravel, or crushed, graded stone such as granite, quartz, limestone or other durable stone meeting ASTM C 33 except that gradation may vary to achieve desired finish and texture.
D. Color - All colors added shall be inorganic (natural or synthetic) iron oxide pigments meeting ASTM C 979 excluding the use of a cement grade of carbon black pigment, and shall be guaranteed by the pigment manufacturer to be lime-proof. The amount of pigment shall not exceed 10% by weight of the cement used.
E. Admixtures - ASTM C 494
F. Water - Shall be potable tap water free from impurities.
G. Air Entrainment - Wet cast mixtures shall maintain 5% to 7% air entrainment where surfaces are exposed to freeze-thaw. Admixture shall meet ASTM C 260.
VI. PROPERTIES OF MIX DESIGN
A. The manufacturer shall be responsible to design a mix which achieves both the strength and the surface finish desired.
B. Compressive strength shall be not less than 6500 psi at 28 days when tested in accordance with the requirements of this specification.
C. The average water absorption of Cast Stone shall not exceed 6% by dry weight when tested in accordance with the requirements of this specification.
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A. Cast Stone shall be reinforced with new billet steel reinforcing bars meeting ASTM A 615, grade 40 or grade 60, when necessary for safe handling, setting and structural stress, and the size of the reinforcing shall be specified. If the surfaces are to be exposed to the weather, the reinforcement shall be galvanized or epoxy coated when covered with less than 2 inches of material for bars larger than 5/8 inch and 1 1/2 inches for bars 5/8 inch or smaller. The material covering in all cases shall be at least twice the diameter of the bars.
B. Cast Stone panels shall be reinforced as may be required for handling and to allow for temperature changes and structural stress. There shall be a minimum steel reinforcement amounting to 1/4 percent of the sectional area of the panel and should the panel be greater than 12 inches in any sectional dimension, the temperature steel shall be placed in both directions.
C. Where applicable, cold-drawn steel wire reinforcement meeting ASTM A 82, Welded Wire Fabric reinforcement meeting ASTM A 185 or ASTM A 497 or steel bar or rod mat reinforcement meeting ASTM A 184 may be used.
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VIII. COLOR AND FINISH
A. The manufacturer shall submit to the Architect, for selection approval, samples of the Cast Stone specified which will be typical of the general range of color and finish to be furnished.
B. Exposed surface, unless otherwise specified, shall exhibit a typically fine grained texture similar to natural stone with no bugholes permitted.
D. Color and texture of Cast Stone shall be generally equal to the approved sample when viewed in direct daylight at a 10 foot distance.
E. The range of total acceptable color (lightness, color saturation and hue) variations shall not exceed CIELAB 3.0 provided that the difference in hue alone does not exceed CIELAB 1.0 as defined by the International Commission of Illumination, 1976 Standards.
A. Stone dimensions - The numerically greater of plus or minus 1/8 inch or length/360.
B. Setting tolerances - plus or minus 1/8 inch allowable out of plane from adjacent unit.
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A. Testing shall be performed in accordance with ASTM C 31, ASTM C 39 and ASTM C 642 except that 2 inch cube specimens shall be used, oven-dried in accordance with ASTM C 97.
B. Test results shall be determined by the average of three specimens per test.
C. The results of compression tests shall be divided by a factor of 0.8 when saw-cut or core-drilled specimens are used.
XI. DELIVERY AND STORAGE
A. All Cast Stone shall be carefully loaded and packed for transportation, exercising customary and reasonable precaution against damage while in transit.
B. All Cast Stone shall be received and unloaded at the project site by competent workmen with the necessary care and handling to avoid damage and soiling.
C. The Cast Stone material shall be stored clear of the ground on non-staining planking or pallets in such a manner as to be protected from damage while in storage. Should Cast Stone be stored for an extended period, cover with polyethylene or other non-staining waterproof material.
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A. All Cast Stone shall be set by experienced masons, accurately and in accordance with the shop and setting drawings. Unless otherwise noted, every stone shall be set in a full bed of mortar with all vertical joints flushed full. All anchors and dowels shall be firmly placed and all anchor holes and dowel holes and similar holes filled completely with mortar or non-shrink grout.
B. All anchors, dowels and other anchoring devices shall be furnished by the setting contractor as shown on approved shop drawings, using whenever possible, standard building stone anchors, commercially available in a non-corrosive material such as galvanized steel, brass, or stainless steel - Type 302 or 304.
C. When setting with mortar, all stones not thoroughly wet shall be drenched with clear water just prior to setting.
D. After each stone has been set, all joints shall be raked to a depth of 3/4 inch from the face for pointing. The face of each stone shall then be sponged off to remove any splashed mortar or mortar smears.
E. Only the ends of lugged sills and similar stones shall be embedded in mortar. The balance of joint to be left open until pointing of stone work, then tuck points on face only to a depth of 3/4 inch.
F. All cornices, copings, projecting belt courses, steps, platforms and in general, all stone areas either partially or totally horizontal, shall be set with unfilled vertical joints. After setting, insert properly sized balk-up material or backer rod to proper depth, prime the ends of the stone, gun in sealant.
G. All stone shall be protected from splashing mortar or damage by other trades.
Any foreign matter splashed on the stone should be removed immediately.
XIII. PATCHING AND CLEANING
A. The repair of chipped or damaged Cast Stone shall be done only be mechanics skilled in this class of work with materials furnished by the Manufacturer and according to this direction.
B. Before pointing, the face of all Cast Stone shall be scrubbed with a fibre brush, using soap powder and water and shall then be thoroughly rinsed with clean, running water. Any mortar on the face of the Cast Stone shall be removed. No acids or prepared cleaners shall be used without the approval of the Cast Stone Manufacturer.
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XIV. POINTING AND CALUKING
A. When ready for pointing, the joints shall be dampened and carefully pointed to a slight concave unless otherwise specified by the Architect. No pointing shall be done in freezing weather nor in locations exposed to hot sun, unless properly protected. Pointing mortar shall be composed of 1 part non-staining cement (ASTM C 91), 1 part hydrate lime (ASTM C 207-Type S) and 4 parts of clean, washed sand (ASTM C 144). Coloring pigments may be added as required. The Architect shall approve color pointing mortar before proceeding with pointing.
B. Head joints in coping and similar stones shall be caulked with a joint sealant used in accordance with the manufacturer's instructions.
XV. INSPECTION AND ACCEPTANCE
A. Applicable standards for inspection and quality control shall be ACI Committee 311 Manual of Concrete Inspection and PCI MNI - 117 Manual for Quality Control for Plants and Production of Architectural Precast Concrete Products.
B. Cast Stone shall show no obvious repairs or imperfections other than minimal color variations when viewed with the unaided eye at a 20 foot distance in good typical daylight illumination.
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