Attachment 16 - 04 30 00 Mass Masonry Wall Construction.pdf

Ord and Weitzel Gate Reconstruction Arlington National Cemetery Task Order: W91236-14-0028-21

SECTION 04 30 00

MASS-MASONRY WALL CONSTRUCTION

03/19

PART 1 GENERAL

1.1 GENERAL REQUIRMENTS

It is the intent of this specification to protect historic structures to the greatest extent possible, including the existing stone columns to be reconstructed as part of the Gate Reconstruction portion of this project.

Use the gentlest means possible to perform the work and take the greatest of care to ensure that the historic structures materials are not damaged in the process of the work. In addition to requirements in this section, comply with the NPS Historic Properties guidelines referenced below.

Mass-Masonry is the term for the stone masonry construction of the wing walls and end piers on the Gate Reconstruction portion of this project.

Exposed stone masonry shall be a random coursed broken ashlar bond pattern. The wing wall mass-masonry shall be constructed as approved to match or blend with the aesthetics of the existing exposed historic stone units identified on the exterior side of the existing cemetery boundary wall as determined by the Government and as demonstrated in the Boundary Wall Repair SPC Test Panel Program Report performed by Speweik Preservation Consultants, Inc. dated October 2015. Refer to Part 2 Products paragraph 2.2.2.1 Stone below.

1.2 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

ASTM INTERNATIONAL (ASTM)

ASTM C144 (2011) Standard Specification for Aggregate for Masonry Mortar

ASTM C1489 (2015) Standard Specification for Lime Putty for Structural Purposes

ASTM C150 (2005) Standard Specification for Portland Cement

ASTM C170/C170M (2009) Standard Test Method for Compressive Strength of Dimension Stone

ASTM C270 (2014-a) Standard Specification for Mortar for Unit Masonry

ASTM E2659 (2018) Standard Practice for Certificate Programs

NATIONAL PARK SERVICE (NPS)

NPS Historic Properties (1995) National Standards for the

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Treatment of Historic Properties with Guidelines for Preserving, Rehabilitating, Restoring, and Reconstructing Historic Buildings

NPS TPS Brief 1 (2000) Assessing Cleaning and Water-Repellent Treatments for Historic Masonry Buildings

1.3 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government. Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:

SD-01 Preconstruction Submittals

Quality Control Plan; G

SD-02 Shop Drawings

Detail Drawings

SD-03 Product Data

Stone Coping Flashing; G Cold Weather Installation; G Masonry Cleaning; G Masonry Construction Cleaning Material Qualifications Pigment; G

SD-04 Samples

Stone Coping Flashing; G Stone; G Mock-ups; G Mortar; G

SD-06 Test Reports

Masonry Inspector / Masonry Training Instructor / Consultant; G

SD-07 Certificates

Masonry Training Certificates; G

1.4 QUALITY CONTROL

Submit resumes for all historic masonry workers, demonstrating the minimum experience required. Product manufacturers, vendors, distributors, or suppliers of materials will not be permitted to offer on-site project training certificates or historic masonry consultation services .

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1.4.1 Quality Control Plan

Prior to beginning stonework, submit a written Quality Control Plan.

Include a separate section in the overall project Quality Control Plan specifically addressing the wing wall stone construction. Do not proceed without written approval of the plan. At a minimum, include the following items in the Quality Control Plan:

a. Describe methods of dust containment during the work specific to the restoration and reconstruction work.

b. Describe the methods of protecting surrounding construction, memorial and cemetery markers, columbarium, surrounding landscape, and adjacent bases and properties. Provide drawings of protection.

c. Describe the work procedures, materials, and tools the contractor proposes to use for each Masonry Treatment Requirement (MTR) specified.

d. Describe the sequence of each MTR.

e. Describe how the sequence of MTR and the construction schedule changes as it relates to climate changes and protection of completed work.

f. Describe the methods for surveying the existing boundary wall original ashlar layout, and collecting datum points and plumb lines for the construction of the wing walls.

g. Describe the methods for providing a safe working environment.

h. Describe the methods for constructing a random coursed broken ashlar stonewall system.

i. Describe the method and approach to cleaning mortar smears from the stone masonry surfaces after construction.

j. Describe, in detail, the procedures relating to mortar mixing techniques, procedures, and equipment used at the project site.

k. Describe the complete masonry matching procedures; include equipment, which workers will be assigned each MTR and attend the onsite ASTM E2659 Masonry Training, approach, length of time the masonry materials will be on the project site prior to assembly.

l. Describe the methods and tools used in creating a bead joint mortar profile to match the existing exterior surface of the boundary wall.

1.4.2 Qualifications

1.4.2.1 Masonry Inspector / Masonry Training Instructor / Consultant

Secure the services of a historic masonry consultant with a minimum of ten

(10) years of experience applying NPS Historic Properties as they relate to the work in this Section. Submit three relevant projects within that period that include how NPS Historic Properties were applied to the work of similar scope and scale and what jurisdiction or agency was involved in approving the work. The consultant's services include: observation and

SECTION 04 30 00 Page 3 consultation during mortar mixing, the construction of a Test Panel for the wing wall construction, recommending appropriate cleaning methods and materials, recommending construction options, providing an ASTM C2659 training program, and providing quality control services during construction. The consultant shall keep a complete record of all inspections and shall submit written reports to the Quality Control Supervisory Representative reporting on the quality of masonry construction. Submit copies of masonry inspection reports. A total of four

(4) inspections are required for the wing wall construction.

1.4.2.2 Masonry Training Certificates

Provide individual worker ASTM Masonry Training Certificates by each applicable MTR specified herein .

1.4.2.3 Masonry Firm

The firm performing the masonry work shall have a minimum of five years of experience on similar projects. The firm shall have completed work similar in material, design, and extent to that indicated for this Project and shall demonstrate a record of successful in-service performance. Proven implementation of NPS Historic Properties and related Preservation Briefs are required.

1.4.2.4 Field Supervision

Retain an experienced full-time supervisor on the project site at all times when stone masonry construction is in progress. A single individual shall be responsible for supervising the stone masonry construction work throughout the duration of the project.

1.4.2.5 Masonry Applicator

Employ craftspeople that are experienced with and specialize in stonewall system work of the types they will be performing. All masonry treatments must be performed by a craftsperson that is familiar with historic masonry construction, has participated and passed the required onsite ASTM E2659 Masonry Training, and has worked on historic masonry projects for at least five years. Only skilled journeyman masons who are ASTM trained and are familiar and experienced with the materials and methods specified may be used.

1.4.3 Project Training Definition and Use

In addition to five years of demonstrable experience on masonry restoration projects, contractor must offer workers project-training certificate(s) within the framework of ASTM E2659. Project training certificates are earned by individual workers and issued with the understanding that they are for limited time use, enforceable only to this specific project and for a specific MTR. It is not necessary, nor a requirement of this specification, that all restoration workers obtain all project training certificates offered. Rather it is desirable that workers be trained for each project specific task they will perform in order to ensure the highest quality results from the work of this Section.

The following four (4) ASTM E2659 onsite MTR training certificates apply to this project:

a. Test Panel Stonewall in a Random Coursed Broken Ashlar (1-day)

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b. Lime Mortar Mixing and Preparation/Installation (1-day)

c. Repointing Mortar Joints with a Bead Joint Profile Finish (1-day)

d. Coping and Flashing Detail Installation (1-day)

1.4.4 Masonry Mock-ups

After approval of the Quality Control Plan and submittals, the contractor shall build a 6' section of the proposed wing wall according to the drawings and match the existing bond pattern on the exterior (facing out) existing boundary wall of the cemetery.

Mock-ups shall demonstrate the methods and quality of workmanship to be performed in each masonry treatment requirement (MTR). Provide a mock-up for each MTR indicated in related specification Sections. Mock-ups shall be built on a properly designed concrete foundation.

a. Prepare mock-ups under the same weather conditions expected during the remainder of the work.

b. Throughout construction, retain approved mock-up wall in undisturbed condition, suitably marked, as a standard for judging completed work.

c. Review manufacturers' product data sheets to determine suitability of each product for each surface.

d. Apply products using manufacturer-approved application methods, determining actual requirements for application.

e. Obtain approval as to the treatment approach, design, and workmanship to include, but not limited to the verification of all material applications and finishes as specified to the requirements of color, texture, profiles, and finishes before proceeding with work. Review and compare workmanship quality standards to the Government Quality Assurance SPC Project Test Panel Program near STA 34+50. Refer to the Boundary Wall Repair SPC Test Panel Program Report performed by Speweik Preservation Consultants, Inc. dated October 2015.

1.4.5 Detail Drawings

Submit detail drawings including plans, elevations and details of mass-masonry stone wall and masonry stone veneer construction.

1.5 DELIVERY, STORAGE, AND HANDLING

Labeling of packages shall clearly define contents, manufacturer, and batch identification. Detergents, masonry cleaners, paint removers, solvents, epoxies and other chemicals used for masonry cleaning shall be in sealed containers that legibly show the designated name, formula or specification number, quantity, date of manufacture, manufacturers' formulation number, manufacturers' directions including any warnings and special precautions, and name of manufacturer. Store materials in weather tight structures, which will exclude moisture and contaminants.

Accessories shall be stored avoiding contamination and deterioration.

Admixtures which have been in storage onsite for six months or longer, or

SECTION 04 30 00 Page 5 which have been subjected to freezing, shall not be used unless retested and proven to meet the specified requirements.

1.6 FIELD CONDITIONS

1.6.1 General Ambient Conditions

Masonry, mortar, and concrete shall not be placed when weather conditions detrimentally affect the quality of the finished product. No masonry or mortar shall be placed when the air temperature is below 40 degrees F in the shade. When air temperature is likely to exceed 95 degrees F masonry and mortar shall have a temperature not exceeding 95 degrees F when applied. Materials to be used in the work shall be neither produced nor applied during periods of rain or other precipitation. Stop material applications, and protect all in-place material from exposure, during periods of rain or other precipitation. Masonry surfaces shall be cleaned only when air temperatures are above 40 degrees F and will remain so until masonry has dried out, but for not less than 7 days after completion of the work .

1.6.2 Masonry Installation Conditions

Do not perform any masonry repointing or wall construction unless air temperatures are between 40 degrees F and 95 degrees F and will remain so for at least 4 weeks (31 days) after completion of work. Phase repointing and wall construction during hot weather by shading the work area or schedule installation of materials during cooler evening hours to prevent premature evaporation of the water from the mortar. Do not use frozen materials or materials mixed or coated with ice or frost. Do not lower the freezing point of mortar by the use of admixtures or anti-freeze agents.

Do not add chlorides to the mortar. Prevent repointing or construction mortar from staining the face of the masonry or other exposed surfaces.

Immediately remove all repointing mortar that comes in contact with such surfaces. Cover partially completed work when work is not in progress.

Protect ledges and projections from mortar droppings. If the Contractor fails to protect against damage as a result of work of this Section, such damage shall be the Contractor's responsibility. The Contractor shall restore damaged areas to the complete satisfaction of the Owner at no expense to the Owner. Do not apply products under conditions outside the Government and manufacturers' requirements, which include:

a. Surfaces that are frozen; allow complete thawing prior to installation.

b. Surface and air temperatures below 40 degrees F.

c. Surface and air temperatures above 95 degrees F.

d. When surface or air temperature is not expected to remain above 40 degrees F for at least 4 weeks (31 days) after application.

e. Wind conditions that may blow materials onto surfaces not intended to be treated.

1.7 WARRANTIES

1.7.1 Cleaning Warranty

Warrant cleaning procedures for a period of two years against harm to

SECTION 04 30 00 Page 6 substrate (masonry and mortar) or to adjacent materials including, but not limited to, discoloration of substrate from improper procedures or usage, chemical damage from inadequate rinse procedures, and abrasive damage from improper procedures.

1.7.2 Construction Warranty

Warrant procedures, including repointing and reconstruction work, for a period of two years against: discoloration or mismatch of new mortar to adjacent original historic mortar, discoloration or damage to masonry from improper mortar clean-up, loss of bond between masonry and mortar, fracturing of masonry edges from improper mortar joint preparation procedures or improper mortar formulation, and occurrence of efflorescence.

PART 2 PRODUCTS

2.1 CLEANING MATERIALS

Selection of appropriate cleaning products requires a clear understanding of the masonry materials to be cleaned, a rationale for the cleaning, and an understanding of the anticipated level of cleanliness expected from the cleaning program. Caution against over-cleaning of surfaces, which may be cause damage. For example, if cleaning reveals unexpected conditions:

suspend the cleaning action, protect the exposed area and notify the Contracting Officer. Research has determined that overly aggressive cleaning methods and materials can cause subtle, long-term damage to masonry units. Use products that have a minimum 5-year performance record on similar projects. Selection of the products shall be predicated on long-term negative effects to the masonry rather than current level of cleanliness of the comparable structure. Follow NPS TSP Brief 1.

2.1.1 Cleaning Implements

Furnish brushes that contain natural or nylon fiber bristles only. Do not use wire brushes. Scrapers and application paddles shall be made of wood with rounded edges. Metallic tools are not permitted.

2.1.2 Water

Obtain potable water from a local source. Filter to remove minerals resulting in a neutral pH, prior to application.

2.2 MATERIALS

Use materials, physical and chemical properties, and composition of masonry and mortar in construction work that match the original existing masonry boundary wall. Masonry materials used for wing wall construction and the veneer of the stone column piers shall match the Carter Bluestone of the existing historic cemetery boundary wall and bluestone coping stone in composition, color, texture, strength, size, finishing, and porosity.

2.2.1 Mortar

The mortar shall coexist with the stone in a sympathetic, supportive and, if necessary, sacrificial capacity. The mortar shall be lime based and have greater vapor permeability and be softer (measured in compressive strength) than the stone.

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2.2.1.1 Matching

The mortar shall match the original existing boundary wall material in color, texture and tooling. The aggregate shall match the aggregate in the original existing mortar by color, shape, and particle size distribution using ASTM C144; ASTM E11 sieves. Use of admixtures is subject to approval.

2.2.2 Masonry Materials

2.2.2.1 Stone

Stone shall match in type, color, shape, size, texture, and finish-profile the appearance of the existing historic stone units identified in the Boundary Wall Repair SPC Test Panel Program Report (Carter Bluestone) dated October 2015 and in compliance with ASTM C170/C170M.

2.2.2.2 Stone Face and Edge Finish

The stone face shall be left rough, just as it comes from the quarry, and the joints, or edges, shall be pitched off to a line by hand using a 2" carbide tipped chipper or hand set chisel and hammer. Acceptable manufacturer: Trow and Holden, Barre, VT, 802-476-7221 or approved equal.

2.2.2.3 Stone Coping

The stone coping shall be bluestone measuring 4 inches thick by the width indicated on the drawings and the pieces shall be divided equally to the length of the wall and as required to achieve the indicated vertical and horizontal curves. See drawing for more details.

2.2.3 Masonry Elements

2.2.3.1 Stone Coping Flashing

All joints in coping stone shall receive 16 oz./22 Mil (.0216") gauge copper flashing and shall be a commercially available product designed for installation in mortar joints to help protect against water infiltration.

The flashing shall be installed only under each coping joint.

2.3 EQUIPMENT

2.3.1 Cleaning Equipment

Cleaning equipment shall not cause staining, erosion, marring, or other damage or changes in the appearance of the surfaces to be cleaned.

Contractor shall utilize manual methods for cleaning surfaces.

2.3.1.1 Sandblasting

Sandblasting shall not be utilized.

2.3.1.2 Water Blasting

Water blasting equipment shall not be utilized. .

2.3.2 Spray Equipment

Spray equipment for chemical cleaners shall be low-pressure tanks or chemical pumps suitable for chemical cleaner indicated, and shall be

SECTION 04 30 00 Page 8 equipped with stainless steel, cone-shaped spray-tip. Spray equipment for water shall disperse water through a fan-shaped spray tip at an angle of not less than 15 degrees. Spray equipment shall deliver water at a pressure not greater than 100 psi and at a volume between 2.5 and 3 gpm.

Spray equipment for heated water shall be capable of maintaining temperature, at flow rates indicated, between 140 and 180 degrees F. Keep the spray-tip at a 10-inch minimum distance from the wall surface during operations.

2.3.3 Compressed Air Supplie s

Compressed air equipment shall deliver clean, oil, and moisture free compressed air at the surface to be cleaned. The compressed air line shall have at least two in-line air filters to remove oil and moisture from the air supply. Test the compressed air supply during each shift for the presence of oil and moisture.

PART 3 EXECUTION

3.1 MORTAR MIX DESIGN

a. Mix one part portland cement, 2 parts lime putty and 8 parts aggregate. This mortar shall be continuous during the construction and repointing process. This mix design meets the Proportion Specification in ASTM C270, Type O.

b. Mix non-fading color pigments into the mortar as required to match existing historic mortar.

c. Match historic mortar aggregate as closely as possible. Adjust aggregate gradation, shape, and size to minimize mortar shrinkage during the initial set and curing period of 4 weeks.

3.2 LIME PUTTY

The use of non-hydraulic lime putty as the mortar binder must meet ASTM C1489. High calcium or dolomitic lime putty is permitted. Approved lime putty manufacturers are listed below:

a. U.S. Heritage Group, Chicago, IL

b. Graymont Dolime, Genoa, OH

3.3 PORTLAND CEMENT

The use of portland cement must meet ASTM C150 Standard Specification for Portland Cement.

3.4 AGGREGATE

Aggregate for masonry mortar shall match the original mortar in color, texture, shape, and particle size distribution (gradation). Adjust particle size of the aggregate to prevent mortar from de-bonding with surrounding stone in the wider joint profiles. Aggregates to comply with ASTM C144 Standard Specification for Aggregate for Masonry Mortar.

3.5 PIGMENT

Pigments shall comprise of natural and synthetic, milled, and blended iron

SECTION 04 30 00 Page 9 oxides. Carbon may be added for darker colors but shall not exceed 4 percent. Pigment shall be inert, stable to atmosphere conditions, sunfast, weather resistant, alkali resistant, water insoluble, lime proof, nonbleeding and free of deleterious fillers and extenders. Maximum particle size shall be 0.0017 inches. Contractor shall follow all manufacturer's recommendations for handling, tooling, and storage.

Approved pigment manufacturer is below:

a. Solomon Colors, PO Box 8288, Springfield, Illinois 62791 or approved equal.

Mix pigment with masonry mortar in accordance with manufacturer's instructions. Add proper number of pigment color units to mortar mix in accordance with manufacturer's table and mix materials with mechanical mixer. Do not load mixer beyond recommended capacity.

Ensure uniform color and workability of colored mortar by source, brand, type, color, weight of cementitious materials, and sand is consistent throughout project. Also, maintain the quantity of water is consistent throughout project. Do not re-temper colored mortar with addition of water.

3.6 PREPARATION

3.6.1 Material Handling and Associated Equipmen t

3.6.1.1 Mixing, Transporting, and Placing Job Materials

Provide mixing equipment, transporting, placing, and confining masonry to support uninterrupted placement operations. Each batch shall be used within a period of 2.5 hours after mixing is complete. Re-tempering of the mortar is permitted within the allotted timeframe specified herein.

Equipment used for mixing, conveying, and placing of materials shall be clean, free of old materials and contaminants, and shall conform to the material manufacturer's recommendations.

3.6.1.2 Associated Equipment

Provide associated equipment, such as mixer timing equipment, valves, pressure gauges, pressure hoses, other hardware, and tools, as required to ensure a continuous supply of material and operation control.

3.6.2 Protection

Protect persons, motor vehicles, adjacent surfaces, surrounding site features or buildings, equipment, and landscape materials from construction operations. Erect temporary protection covers, which will remain in operation during the course of the work, over pedestrian walkways and at personnel and vehicular points of entrance and exit.

3.6.2.1 Worker Exposures

Exposure of workers to chemical substances shall not exceed the limits established by ACGIH 0100, or those required by a more stringent applicable regulation.

3.7 EQUIPMENT AND TECHNIQUES DEMONSTRATION

Demonstrate equipment and techniques of operation in an approved location.

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Dependable and sufficient equipment, appropriate and adequate to accomplish the work specified, shall be assembled at the work site in sufficient lead time before the start of the work to permit inspection, calibration of weighing and measuring devices, adjustment of parts, and the making of any repairs that may be required. Maintain the equipment in good working condition throughout the project.

3.8 MASONRY CLEANING

Masonry materials shall not be damaged or marred in the process of cleaning. Cleaning shall conform to NPS TPS Brief 1 . Protect open joints to prevent water and cleaner intrusion into the interior of the structure from pressure spraying. Protect non-masonry materials and severely deteriorated masonry by approved methods prior to initiation of cleaning operations. Surfaces shall be evenly cleaned with no evidence of streaking or bleaching. The cleaning process shall not affect the density, porosity, or color of the masonry or mortar. Cleaned masonry shall have a neutral pH. Use the gentlest methods possible for cleaning masonry to achieve the desired results. Make test patches to determine a satisfactory cleaning result. Cleaning shall proceed in an orderly manner, working from bottom to top from one end of each elevation to the other. Perform cleaning in a manner, which results in uniform coverage of all surfaces, including corners, moldings, interstices and which produces an even effect without streaking or damage to masonry. The cleaning materials, equipment, and methods shall not result in staining, erosion, marring, or other damage to the surfaces of the structure. The work shall provide for the complete cleaning of all exposed masonry surfaces of the structures, removing all traces of mortar residue and smears. The following sequence of methods shall be used to determine the least aggressive, effective cleaning method for the wing walls:

a. Water with brushes

b. Water with mild soap

c. Water with stronger soap

3.8.1 Test Patches

Demonstrate the materials, equipment, and methods to be used in cleaning in a test section approximately 3 feet by 3 feet. The location of the test section, and the completed test section is subject to approval. Adjust the cleaning process as required and the test section rerun until an acceptable process is obtained. Locate test patches in inconspicuous areas of the structures. The areas tested shall exhibit soiling characteristics representative of those larger areas to be cleaned. Also, conduct tests on areas to be stripped of paint. Allow tested areas to dry before a determination is made on the effectiveness of a particular treatment.

3.8.2 Water Cleaning

3.8.2.1 Hand Scrubbing

Scrub surfaces to be cleaned in order to remove surface contaminants.

Pre-wet surfaces and use hand-held natural bristle or nylon brushes. Do not use wire brushes.

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3.8.2.2 Rinsing

Rinse scrubbed surfaces clean of all contaminants and cleaning solutions with water in a low-to-moderate pressure spray, working upwards from bottom to top of each treated area. The rinsing cycle shall remove all traces of contaminants and cleaning solutions.

3.9 MASONRY CONSTRUCTION

Match the constructed wall areas with adjacent existing approved mock-up surfaces in all respects. Demonstrate the materials, methods, and equipment proposed for use in the construction work in test panels. The location, number, size and completed test panels are subject to approval.

Use products in accordance with the manufacturers' instructions.

3.9.1 Stone Masonry Assembly

The stone units shall have a pitched face set into the specified mortar with mortar joints not to exceed ½ inch in width. The units shall be set in a random coursed broken ashlar bond style on both sides of the wing walls. The vertical joints of each course should break with the joints of the course below. The lap should be not less than 4 inches. A through wall stone (header stone) shall be set every five square feet in the wing walls. Rake back the bedding mortar 1-1/4 inches from the face of the wall after setting. This is in preparation for the repointing application to create the bead joint profile finish. Do not repoint joints until the full wing wall is completed.

3.9.2 Presoaking Masonry / Mortar Consistency / Lifts

Use the specified mortar for setting of the stone masonry. Soak exposed surfaces of stone masonry adjacent to joint with water prior to repointing. Allow time for excess water to run off and evaporate prior to repointing. Joint surfaces shall be damp but free from standing water.

Maintain a water sprayer on site at all times during the repointing process. The mortar material shall resemble the consistency of brown sugar during installation. This drier consistency enables the material to be tightly packed into the joint, allows for cleaner work, and prevents shrinkage cracks as the mortar cures. Repoint joints in layers or "lifts" where the joints are deeper than 1-1/4 inch. Apply in layers not less than 1/2 the depth but not more than 1-1/4 inch or until a uniform depth is attained. Follow methods and procedures identified in the ASTM on-site masonry training, and NPS TSP Brief 2.

3.9.3 Compression / Joint Finish / Curing

a. Compress each layer thoroughly and allow it to become thumbprint hard before applying the next layer.

b. When mortar is thumbprint hard at the surface of the wall, finish the joints to match the original historic joint profile replicated on the boundary wall SPC test panel.

3.9.4 Protection

Keep the mortar from drying out too quickly or from becoming too wet.

Protect it from direct sun and high winds for the first 72 hours after installation or from driving rain for the first 24 hours, breathable Burlene material is recommended. Do not create a greenhouse effect by

SECTION 04 30 00 Page 12 sealing off air movement in an attempt to protect the wall with plastic.

Allow for air circulation to facilitate the carbonation process.

3.9.5 Pitching Stone Units

Chisel excess stone material to square up edges and fit into coursing work.

Use tools and techniques identified during the MTR training session.

3.9.6 Setting Stone Units

Butter vertical joints for full width before setting and set units in full bed of mortar, unless otherwise indicated. Remove mortar used for setting masonry units before mortar sets to the repointing depth. Repoint new mortar joints in the wing wall to comply with requirements for repointing masonry units. Cover the four sides and back of the space with sufficient mortar to ensure that there will be no air spaces when the stone is set.

Line up and set the stone by tapping it into place with a wooden or rubber mallet. Use smaller pieces of stone to infill the center of the wall as work progresses. The stonewall shall be completely solid with stone and mortar. The use of only mortar to fill the center of the wall is not permitted .

3.10 FINAL CLEANING

No sooner than 72 hours after completion of the masonry construction, and prior to the repointing work and after joints are completely cured after 4 weeks, faces and other exposed surfaces of masonry shall be washed down with water applied with a soft bristle brush, then rinsed with clean water. Discolorations, which cannot be removed by these procedures, shall be considered defective work. Perform cleaning work when temperature and humidity conditions allow the surfaces to dry rapidly. Protect adjacent surfaces from damage during cleaning operations.

3.11 PROTECTION OF WORK

Protect work against damage from subsequent operations

3.12 DEFECTIVE WORK

Defective work shall be repaired or replaced, as directed, using approved procedures.

3.13 FINAL INSPECTION

Following completion of the work, inspect the wing walls for damage, staining, and other distresses. The stone and all mortar joints shall be inspected for cracking, crazing, delamination, unsoundness, staining and other defects. The finish, texture, color and shade, and surface tolerances of the patches and mortar joints shall be inspected to verify that all requirements have been met. Repair or replace joints and stone surfaces exhibiting defects as directed.

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