042000_-_Unit_Masonry.pdf

Samuel S. Stratton VA Medical Center

Revise 6B for Dialysis

Project #528A8-15-801

Bid Documents: 07/23/19

04 20 00 - 1

SECTION 04 20 00

UNIT MASONRY

PART 1 - GENERAL

1.1 SUMMARY

A. Section Includes:

1. Concrete masonry units (CMU) assemblies for exterior walls.

1.2 RELATED REQUIREMENTS

A. Sealants and Sealant Installation: Section 07 92 00, JOINT SEALANTS.

1.3 APPLICABLE PUBLICATIONS

A. Comply with references to extent specified in this section.

B. ASTM International (ASTM):

1. C90-14 - Load-Bearing Concrete Masonry Units.

1.4 SUBMITTALS

A. Submittal Procedures: Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, AND SAMPLES.

B. Manufacturer's Literature and Data:

1. Description of each product.

C. Certificates: Certify products comply with specifications.

1. Solid and load-bearing concrete masonry units.

1.5 DELIVERY

A. Deliver products in manufacturer's original sealed packaging.

B. Mark packaging, legibly. Indicate manufacturer's name or brand, type, color, production run number, and manufacture date.

C. Before installation, return or dispose of products within distorted, damaged, or opened packaging.

1.6 STORAGE AND HANDLING

A. Store products above grade, protected from contamination.

B. Protect products from damage during handling and construction operations.

1.7 FIELD CONDITIONS

A. Hot and Cold Weather Requirements: Comply with

ACI 530.1/ASCE 6/TMS 602.

1.8 WARRANTY

A. Construction Warranty: FAR clause 52.246-21 "Warranty of Construction."

Project #528A8-15-801

Bid Documents: 07/23/19

04 20 00 - 2

PART 2 - PRODUCTS

2.1 PRODUCTS - GENERAL

A. Provide each product from one manufacturer.

2.2 UNIT MASONRY PRODUCTS

A. Concrete Masonry Units (CMU):

1. Hollow and Solid Load-Bearing Concrete Masonry Units: ASTM C90.

a. Unit Weight: Normal weight.

2. Sizes: Modular, 200 mm by 400 mm (8 inches by 16 inches) nominal face dimension; thickness as required to match existing.

PART 3 - EXECUTION

3.1 INSTALLATION - GENERAL

A. Install products according to manufacturer's instructions.

1. When manufacturer's instructions deviate from specifications, submit proposed resolution for Contracting Officer's Representative consideration.

B. Keep finish work free from mortar smears or spatters and leave neat and clean.

C. Wall Openings:

1. Fill hollow metal frames built into masonry walls and partitions solid with mortar as laying of masonry progresses.

2. When items are not available when walls are built, prepare openings for subsequent installation.

D. Tooling Joints:

1. Do not tool until mortar has stiffened enough to retain thumb print when thumb is pressed against mortar.

2. Tool while mortar is soft enough to be compressed into joints and not raked out.

3. Finish joints in exterior face masonry work with jointing tool, and provide smooth, water-tight concave joint unless specified otherwise.

4. Tool Exposed interior joints in finish work concave unless specified otherwise.

E. Wall Units:

1. Lay out field units to provide one-half running bond, unless indicated otherwise.

2. Align head joints of alternate vertical courses.

Project #528A8-15-801

Bid Documents: 07/23/19

04 20 00 - 3

3. At sides of openings, balance head joints in each course on vertical center lines of openings.

4. Minimum Masonry Unit Length: 100 mm (4 inches).

F. Before connecting new masonry with previously laid masonry, remove loosened masonry or mortar, and clean and wet work in place as specified under wetting.

3.2 INSTALLATION - CONCRETE MASONRY UNITS

A. Laying:

1. Lay concrete masonry units with 9 mm (3/8 inch) joints, with a bond overlap of minimum 1/4 of unit length, except where stack bond is indicated on drawings.

2. Do not wet concrete masonry units before laying.

3. Lay first course in a full mortar bed.

4. Lay concrete masonry units with full face shell mortar beds and fill head joint beds for depth equivalent to face shell thickness.

5. Lay concrete masonry units so cores of units, that are to be filled with grout, are vertically continuous with joints of cross webs of such cores completely filled with mortar. Unobstructed core openings minimum 50 mm (2 inches) by 75 mm (3 inches).

6. Grout cells of concrete masonry units solid as specified.

3.3 GROUTING

A. Preparation:

1. Clean grout space of mortar droppings before placing grout.

B. Placing:

1. Place grout in grout space in lifts as specified.

2. Consolidate each grout lift after free water has disappeared but before plasticity is lost.

3. Do not slush with mortar or use mortar with grout.

C. Puddling Method:

1. Consolidate by puddling with grout stick during and immediately after placing.

D. Low Lift Method:

1. Construct masonry to 1.5 m (5 feet) maximum height before grouting.

2. Grout in one continuous operation and consolidate grout by mechanical vibration and reconsolidate after initial water loss and settlement has occurred.

Project #528A8-15-801

Bid Documents: 07/23/19

04 20 00 - 4

3.4 CONSTRUCTION TOLERANCES

A. Lay masonry units plumb, level and true to line within tolerances according to ACI 530.1/ASCE 6/TMS 602 and as follows:

B. Maximum variation from plumb:

1. In 3000 mm (10 feet) - 6 mm (1/4 inch).

2. In 6000 mm (20 feet) - 9 mm (3/8 inch).

3. In 12,000 mm (40 feet) or more - 13 mm (1/2 inch).

C. Maximum variation from level:

1. In any bay or up to 6000 mm (20 feet) - 6 mm (1/4 inch).

2. In 12,000 mm (40 feet) or more - 13 mm (1/2 inch).

D. Maximum variation from linear building lines:

1. In any bay or up to 6000 mm (20 feet) - 13 mm (1/2 inch).

2. In 12,000 mm (40 feet) or more - 19 mm (3/4 inch).

E. Maximum variation in cross-sectional dimensions of columns and thickness of walls from dimensions shown:

1. Minus 6 mm (1/4 inch).

2. Plus 13 mm (1/2 inch).

F. Maximum variation in prepared opening dimensions:

1. Accurate to minus 0 mm (0 inch).

2. Plus 6 mm (1/4 inch).

3.5 CLEANING AND REPAIR

A. General:

1. Clean exposed masonry surfaces on completion.

2. Protect adjoining construction materials and landscaping during cleaning operations.

3. Cut out defective exposed new joints to depth of approximately 19 mm

(3/4 inch) and repoint.

4. Remove mortar droppings and other foreign substances from wall surfaces.

B. Concrete Masonry Units:

1. Immediately following setting, brush exposed surfaces free of mortar or other foreign matter.

2. Allow mud to dry before brushing.

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