SPEC NOTE:  This Section is to be used as a mediumscope thin calcium silicate unit Section and includes units used in veneer and cavity wall construction.
Section 04 42 00
LIMESTONE DIMENSION STONE CLADDING

PART 1 - GENERAL
1.01	SECTION INCLUDES
A.	Design Services: Provide a Proprietary Design/Build Thin Calcium Silicate Unit, modified curtain wall cladding system for project use which includes all materials and labor as required to provide a completed system including, but not limited to the following:
1.	Design, Coordinate, and provide the Precision Walls System’s proprietary aluminum anchor installation system complete with all anchors, sealants, and components as required for a complete installation that is watertight and designed to withstand applicable building code wind loads.
2.	Provide the services of a registered structural engineer in the State of [_________], to provide engineering approval for the system in the form of a system suitability review and compliance document.  This project specific document will include an evaluation of wind pressures, anchoring system dead load and fastener pull out analysis.  Subject compliance document will be signed and stamped by a registered structural engineer in the State of________________________.

1.02	RELATED SECTIONS
A.	 [Section 04220 - Concrete Masonry Units:  Structural substrate.]
B.	 [Section 04435 - Dimension Stone: Limestone veneer].
C.	 [Section 05410 - Load-Bearing Metal Studs:  Structural substrate.]
D.	Section 07210 - Building Insulation:  Insulation for cavity spaces.
E.	Section 07620 - Sheet Metal Flashing and Trim:  Reglets for flashing.
F.	Section 07900 - Joint Sealers:  Rod and sealant.
1.03	DESIGN REQUIREMENTS:
A.	The Gridworx extruded aluminum channels are a design/build system.  The anchors and stone are designed to attach to the substrate at [16"][_____] centers.  Precision Wall Systems, Inc. is responsible for providing engineering approval for the system.  Engineering for the exterior building wall support system is the structural engineer of record’s responsibility.
B.	The Thin Limestone Dimension Stone veneer shall be anchored at spacings to meet all Building Codes governing this project, including wind load requirements and wind pressures design loads as required

1.04	QUALITY ASSURANCE
A.	Installer: Company or person specializing in commercial masonry or stone work  [with [__________] years [documented] experience]. 
1.05	TESTS
SPEC NOTE:  Request analysis and testing reports only for larger projects, or where special conditions warrant the additional cost of such testing.
A.	Submit [analysis] [and] [testing] of Thin Limestone Dimension Stone Units to requirements of Section [01001] [________].
B.	Test samples in accordance with indicated standards.
1.06	PRODUCT DATA
A.	Submit manufacturers data sheets for the extruded aluminum channels, Thin Limestone Dimension Stone Units, weep vents, and sealant materials.
1.07	SAMPLES
SPEC NOTE:  Edit the following two paragraphs for submission of physical samples for selection of finish, color, and/or texture.
A.	Submit samples to requirements of Section [01001] [________].
B.	Submit [one] [____] sample of Thin Limestone Dimension Stone Units to illustrate color and texture.
1.08	SHOP DRAWINGS
A.	The Gridworx mechanical stone hanging system is a thin stone cladding system.  Generally, the Thin Dimension Stone Units will be delivered to the job site in standard sizes.  Field modifications are required to incorporate this system with actual project conditions and the architect’s design elements.  As such, the installer should be familiar with these elements thereby relieving the necessity of submittal drawings.
1.09	MOCKUPS
A.	Construct mockup of Thin Limestone Dimension Stone Units to requirements of Section [01001] [_____].
B.	Construct typical mockup panel [48" x 48"] [___ x ___] to illustrate units, coursing, sealant joints , and extruded aluminum support channels.
C.	Construct mockup to illustrate [backup wall,] [exterior sheathing,] [air barrier,] [moisture barrier] [wall insulation,] [weep vents,] [and] [through wall flashing].
D.	Mockup may [not] remain part of the finished Work.
E.	The approved jobsite mockup panel shall be used to determine the level of workmanship expected on the buildings veneer installation.

1.10	DELIVERY, STORAGE, AND HANDLING
A.	Refer to Section [01001] [01600] [_____].
B.	Deliver Thin Limestone Dimension Stone Units to the site in approved protective film.  Prevent damage to units.
C.	Lift skids with proper and sufficiently long slings or forks with protection to prevent damage to units.  Protect edges and corners.
D.	Store units in a manner designed to prevent damage and staining of units.
E.	Stack units on timbers or platforms at least 3” above grade.
F.	Place polyethylene or other plastic film between wood and other finished surfaces of units when stored for extended periods of time.
G.	Cover stored units with protective enclosure if exposed to weather.
H.	Do not use salt or calcium-chloride to remove ice from unit surfaces.
PART II.  PRODUCTS
2.01	MANUFACTURERS:
SPEC NOTE:  In this Article, list the manufacturers acceptable to the specifier.  Consider including the name and telephone number of a local distributor to assist bidders with product sourcing.  Also consider listing the acceptable Product adjacent to each manufacturer’s listing.
A.	Manufacturers of Limestone Dimension Stone Units having Products considered acceptable for use: Arriscraft International Inc.[, as distributed by [_____]]; ARRIS▪clip Adair® Units.
B.	Manufacturers of extruded aluminum channels having products considered acceptable for use Precision Wall Systems, Inc. [, as distributed by [_____]]; Gridworx’s Extruded Aluminum Channels.
2.02	MATERIALS
A.	Thin Adair® Dolomitic Limestone Units: to ASTM C568, Category III - High Density; special shapes as indicated; having the following typical average properties when tested to the identified standard:

	1.	Compressive Strength: 22,900 psi, to ASTM C170.
	2.	Absorption: 0.75 percent, to ASTM C97.
	3.	Density: 167 lbs/ft3, to ASTM C97.
	4.	Modulus of Rupture: 2,250 psi, to ASTM C99.
	5.	Flexural Strength: 1,600 psi to ASTM C880.
	6.	Abrasion Resistance: 18.0 to ASTM C241

B.	Fabricate anchors from extruded aluminum alloy and temper as required to support loads imposed without exceeding allowable design stresses, but not less than strength and durability properties of Alloy 6005-T5.

C.	Threaded Fasteners: 

1.	Steel stud frame fasteners shall be #12 Hex-head Drill flex fasteners or suitable alternate.
2.	Concrete or CMU block substrate will require 3/16” Tap-con or other comperable concrete screw.
3.	Wood frame studs will require #12 Hex-head stainless steel screws.

2.03	FABRICATED UNITS
	A.	Stone Panels: dolomitic limestone panels, as described below:
	1.	Bed Thickness:  [1-3/8"] [[2-1/8"] [___] thick; 
	2.	Panel Sizes: modular sizes [as scheduled] [as indicated on Drawings];
	3.	Finish: [split] [sawn] [rocked] [bush hammered] [flamed] [medium-dressed] [fine-dressed] [polished] finish on exposed faces [and ends]; 
	4.	Color and Pattern:  [[Blue-Grey] [Sepia]] color, [fleuri] [striated] pattern, to match approved sample range.
	
	B.	Sills and Trim:  dolomitic limestone units, sizes and profiles as indicated on Drawings; [split] [sawn] [rocked] [bush hammered] [flamed] [medium-dressed] [fine-dressed] [polished] finish on exposed faces [and ends]; [[Blue-Grey] [Sepia]] color, [fleuried] [striated] pattern, to match approved sample range.

2.04	ACCESSORIES
SPEC NOTE:  The following paragraph indicates several types of through-wall or drip flashing.  Select type on basis of intended function.  Delete paragraph all together if flashing is not required.
A.	Flexible Flashing:  [air/vapor barrier sheet membrane as specified under Section 07270.] [Sheet [polyvinyl chloride] [polyethylene]; [[0.010"] [0.020"] [____]] thick; [________] manufactured by [________________].] [[Galvanized steel] [Stainless steel].]
B.	Weep Vents:  [[Galvanized steel tubes [wick filled]] [________________];[________] manufactured by [________________].] [[Molded polyvinyl chloride grilles] [________]; insect proof; [________] manufactured by [________________].]
C.	Shims - Full bearing (3” or greater vertical dimension) hi-impact resistant plastic shims.
D.	Sealant for joints - Low modulus silicone expansion joint sealant meeting ASTM 719, SWRI validation and manufacturer’s 20-year weather seal warranty such as Dow Corning 790,795 or756.  Prior to installation of the low modulus silicone joint sealant, installer should contact the sealant manufacturer for proper application and compatibility guidelines.
2.05	FABRICATION TOLERANCES
	A.	Except where dimension is formed by a split or rocked finish, fabricate limestone dimension stone to the following tolerances:
	1.	Unit Length:  plus or minus 1/8".
	2.	Unit Height:  plus or minus 1/8".
	3.	Deviation From Square:  plus or minus 1/8", with measurement taken using the longest edge as the base.
		4.    Bed Depth:  plus or minus 1/8".
PART 3 – EXECUTION
3.01	EXAMINATION
A.	Verify that site conditions are ready to receive work.
B.	Beginning of installation means acceptance of site conditions.
3.02	INSTALLATION:
A.	The Gridworx extruded aluminum channels are a design/build system.  Installer must be familiar with the procedures and recommendations and held to the requirements of the Gridworx Mechanical Stone Hanging System Installation Guide furnished by Precision Wall Systems, Inc.

3.03	CUTTING OF THIN LIMESTONE DIMENSION UNITS
A.	Cut Thin Limestone Dimension Stone Units with a wet-saw.
B.	Pre-soak units using clean water prior to cutting.
C.	Clean cut units using a stiff fibre brush and clean water.  Allow units to surface dry prior to placement.
D.	All Thin Limestone Dimension Stone Units shall be cut accurately to shape and dimensions and full to the square, with jointing as shown on drawings 
E.	Any miscellaneous cutting and drilling of Thin Limestone Dimension Stone Units necessary to accommodate other trades will be the responsibility of the installer.
F.	Incidental cutting such as for window frame clips, etc., which is normally not considered to be the responsibility of the Thin Limestone Dimension Stone Unit supplier, will be provided only by arrangement by the contractor with the manufacturer.
3.04	COURSING
A.	Place Thin Limestone Dimension Stone Units to lines and levels indicated.
B.	Shim and adjust supports to set stones accurately in locations indicated with uniform joints of widths indicated.
C.	Place Thin Limestone Dimension Stone Units in [half-running] [third-running] [stack] [________] bond.
D.	Make joints [[1/4"]] [3/8"] [1/2"] thick. 
E.	Install weep vents at [24"] [____] OC horizontally [above through-wall flashing] [above shelf angles], [and] [at bottom of walls] [_________].
F.	Install cavity vents at [top of cavity space] [________________] at same spacing.
G.	Seal joints with backer rods and joint sealant as specified in Section 07 92 00.
3.05	TOLERANCES
A.	Variation in Alignment from Unit to Adjacent Unit:  1/16" maximum.
B.	Variation of Sealant Joint Thickness:  1/8" every 36".
3.06	FLASHING
A.	Extend flashing under veneer system, turn up structural back-up [under the moisture barrier] and [bed into mortar joint of masonry] [seal to concrete] [seal into sheathing over [wood] [steel stud] framed] back-up.
B.	Lap end joints and seal watertight.
3.07	INTERFACE WITH OTHER WORK
A.	Thin Limestone Dimension Stone Units coming in contact with structural work shall be back-checked.
B.	Thin Limestone Dimension Stone Units resting on structural work shall have beds shaped to fit the supports as required.  Maintain a minimum of 1” clear minimum at metal studs and sheathing board) between stone backs and adjacent structure.  (Note: some bolted connections may require more space than this.  Subcontractor shall verify and make provision for these conditions.
	3.08	SITE TOLERANCES
	
	A.	Variation from Plumb: plus or minus 1/4" per 10 feet maximum.
	
	B.	Variation from Level: plus or minus 1/2" per 20 feet maximum.
	
	C.	Variation from Linear Building Line:  plus or minus 1/2" per 20 feet maximum.
	
	D.	Variation in Cross-Sectional Dimensions:  plus 1/2" or minus 1/4".

	3.09	FIELD QUALITY CONTROL
	
	A.	Perform inspection and testing as specified in Section [01 00 00] [01 40 00] [_____].
	
	B.	Consultant Inspection:  Consultant will inspect installed dimension stone and reject stone that is        chipped, cracked, or blemished (streaked, stained or otherwise damaged), as described below.

	1.	Stone will be inspected to be free of spalls, cracks, open seams, pits or other defects that are likely to impair its structural integrity in its intended use.
	2.	Units shall exhibit a texture approximately equal to the approved sample when viewed under diffused daylight illumination at a 20 foot distance. 
	3.	Minor chipping resulting from shipment and delivery shall not be grounds for rejection. Minor chips shall not be obvious under diffused daylight illumination from a 20 foot distance. 
	4.	Dry seams and natural vugs will not be cause for rejection.
	
	C.	Make Good rejected Units as directed by Consultant.
	
	3.10	ADJUSTING AND CLEANING
	
	A.	Refer to Section [01 00 00] [01 74 00] [_____].
	
	B.	Repair chips with patch kits furnished by manufacturer.
	
	C.	Clean stone as work progresses.  

3.11	CLEANING
A.	Clean the Thin Limestone Dimension Stone Units as work progresses.
SPEC NOTE: Edit Paragraph B. as recommended by unit masonry manufacturer. Refer to Arriscraft•CARE.
B.	Post-Construction:  Clean [a 100 sq. ft. area of wall designated by Consultant] [mock-up panel] as directed below and leave for one week.  If no harmful effects appear clean Thin Limestone Dimension Stone Unit Veneer as follows:
1.	Protect windows, sills, doors, trim and other work from damage.
2.	Remove large particles with [stiff fiber brushes] [wood paddles] without damaging surface.  Saturate thin units with clean water and flush off loose dust and dirt.
3.	Scrub with solution of 1 tsp. trisodium phosphate and 1 tsp. household detergent dissolved in 4 cups of clean water using stiff fibre brushes, then clean off immediately with clean water using a hose.
4.	Repeat cleaning process as often as necessary to remove any stains.
C.	Acids are not permitted without written approval.  Protect stonework from rundown or splash when using acid on adjacent materials.
D.	Use alternative cleaning solutions and methods for difficult to clean units only after consultation with thin unit manufacturer.
3.12	PROTECTION
A.	Protect thin units from damage resulting from subsequent construction operations.
B.	Use protection materials and methods which will not stain or damage Thin Limestone Dimension Stone Units.
C.	During construction, tops of walls shall be carefully covered at night, and especially during any precipitation or other inclement weather.
D.	Remove protection materials upon Substantial Performance of the Work, or when risk of damage is no longer present.
E.	At all times, walls shall be adequately protected from droppings.
SPEC NOTE: Consider the inclusion of a Thin Limestone Dimension Stone Unit schedule when multiple sizes, finishes and colors are to be used.  Ensure unit type locations are clearly identified on the drawings.
3.13	SCHEDULE
A.	Following is a schedule of shapes, sizes and finishes to be used on this Project:

1.	Type A: 
2.	Type B: 
END OF SECTION