DESIGN AND CONSTRUCTION STANDARDS
FACILITIES MANAGEMENT SERVICES
DIVISION 4
MASONRY
DIVISION 4
MASONRY
Division 4 of the Carnegie Mellon University Design and Construction Standards Manual
addresses the following masonry standards related to University projects.
04200
04410
04500
04510
UNIT MASONRY
STONE MASONRY VENEER
MASONRY RESTORATION AND CLEANING
MASONRY REPAIR
DESIGN AND CONSTRUCTION STANDARDS
DIVISION 4
FACILITIES MANAGEMENT SERVICES
MASONRY
04200 UNIT MASONRY
All unit masonry work shall comply with the requirements and standards published by the
following:
• Brick Institute of America
• ASTM (all related divisions)
• American Concrete Institute (ACI)
 ACI 530.1-88/American Society of Civil Engineers (ASCE)
 ACI 315-80
The Contractor shall provide unit masonry that develops the following installed
compressive strengths (f'm):
• Clay Unit Masonry (Select from below.)
f'm=2500 psi GRADE MW (minimum)
f'm=3000 psi GRADE SW (minimum)
• Concrete Unit Masonry
f'm=1900 psi GRADE N (minimum)
The use of face brick with a concrete block backup, reinforced with appropriate joint
reinforcing, is the standard at the University. The use of steel stud wall systems must be
reviewed in detail with the University Project Manager and approved.
Concrete masonry units are not an acceptable exterior wall finish at the University.
Single-Source Supplier
Masonry units shall be provided by a single-source supplier and shall be uniform in
texture and color, or have a uniform blend with acceptable ranges of texture and color.
Approvals
The color selections of all material for use on buildings’ exterior surfaces shall be
approved by the University Architect during the design stage of the project. The Design
Consultant shall submit color boards for review and approval. The approved submitted
boards shall be reused during construction as may be required.
Prior to installation of masonry, a 3-ft wide by 4-ft high mock-up wall shall be erected to
further verify that the samples of masonry and mortar are consistent with those selected in
color and textural characteristics, and to represent completed masonry work for quality
and appearance as well as materials and construction. Masonry materials shall not be
ordered by the Contractor until the mock-up panel has been approved by the University
and the Design Consultant. Mock-ups shall be retained and maintained during
construction as a standard for judging completed work.
The Design Consultant shall show the locations of all expansion and control joints, and
their construction details on the Contract documents.
All approvals will be handled through the University Project Manager.
December 1998
P.4-3
DIVISION 4
MASONRY
DESIGN AND CONSTRUCTION STANDARDS
FACILITIES MANAGEMENT SERVICES
Parapet Walls
When masonry parapet walls are necessary, adequate provisions shall be made to assure
that expansion and contraction are in harmony with the building walls and structure
beneath. Where walls are insulated below the parapet and roofline, the parapet walls shall
also be insulated. With no exceptions, all parapet walls shall be completely flashed and
“roofed” from the coping flashing down to a minimum of 12 in. above the horizontal
plane of the roof measured from the top of the 4-in. cant strip.
Protection of the Work
Masonry shall be protected during erection; tops of walls, projections, and sills shall be
covered with waterproof sheeting at the end of each day’s work.
Unless adequate protection against freezing is provided, no masonry work shall be
performed when the temperature is below 36 °F or is predicted to be 36 °F overnight.
Setting accelerators or antifreeze compounds are not permitted.
Mortar Materials
There are three types of mortar materials acceptable for use on University projects: readymixed mortar, masonry cement, and Portland Cement. The Design Consultant shall select
the appropriate type.
Ready-Mixed Mortar or premixed bagged mortar composed of Portland Cement and
hydraulic hydrated lime shall meet the requirements of ASTM C 207 and ASTM C 1142
and shall be used in ordinary masonry construction.
Masonry Cement is usually job-mixed and is composed of Portland Cement and hydrated
lime plus pigmented additives to provide required color variations. The Portland Cement
and color pigment may be factory mixed and then combined with hydrated lime, sand,
and water at the job site. This cement mortar mix is required to meet ASTM C 150 and
shall be used for heavy loads, below-grade masonry construction, or in high-moisture
locations.
Portland Cement shall be used for exposed masonry and shall meet the requirements of
ASTM C 150. Mortar material color samples shall be pre-approved by the University
Architect.
Joints
Joint reinforcement is required in all masonry and composite wall systems in accordance
with the best standards of practice and the National Concrete Masonry Association
(NCMA) reinforcing standards.
The use of products equal or superior to TREMCO Mon, Dymeric, or Lastomeric shall be
used for all expansion, control, and coping joints in masonry and stone. Water stops shall
be of the built-in rubber type.
P.4-4
December 1998
DESIGN AND CONSTRUCTION STANDARDS
FACILITIES MANAGEMENT SERVICES
DIVISION 4
MASONRY
The Design Consultant shall show on the Contract Documents the locations of all
expansion and control joints and their construction details.
Flashing
All coping flashing shall be through-wall type, with appropriate anchorage and
attachments. Counterflashing shall overlap sufficiently to prevent water from entering
behind flashing. Copper shall be used for flashing and counterflashing where exposed to
view. No other metal shall be used in contact with copper.
Coping Stones
All coping stone joints shall be raked to a depth of 0.5 in. and caulked with silicone.
Through-wall flashing shall be installed beneath all coping stone installations.
All coping stones shall be mechanically attached to parapet wall construction using
stainless steel dowels and stainless steel wire.
Steps and Ramps
All masonry steps and ramps shall comply with the Americans with Disabilities Act
(ADA) guidelines. Wherever possible, inclined walkways with a 1:20 slope shall be used
in lieu of 1:12 to 1:20 sloped ramps.
Thresholds
Brick, stone, or metal thresholds shall be provided in a raised position at all exterior door
sills. For the maximum height and type of thresholds permitted, the ADA requirements
shall be consulted. Masonry thresholds shall rest wholly on the building structure and not
on any adjacent walkway, porch, landing, or exterior entrance patio material.
Water Repellent
The use of water-repellent masonry coating for above-grade masonry is prohibited. The
University requires a masonry system that is “breathable.” Resolution of water problems
at above-grade masonry should be accomplished by means other than masonry sealants or
coatings.
Efflorescence
The Design Consultant shall specify efflorescence testing of all brick to be used in
exterior construction.
December 1998
P. 4-5
DIVISION 4
DESIGN AND CONSTRUCTION STANDARDS
MASONRY
FACILITIES MANAGEMENT SERVICES
04410 STONE MASONRY VENEER
The use of stone masonry or stone veneer construction at the University for exterior or
interior use must be reviewed and approved by the University Design Review Committee.
04500 MASONRY RESTORATION AND CLEANING
Bricks or stone masonry shall be cleaned with water and brushes with nonmetal bristles.
Diluted detergents may by used. Repeated gentle washings are preferred to fewer
washings that are abrasive or chemical laden.
Acid content in washing solutions is forbidden on historic buildings but may be used in
amounts not to exceed 5% on new, non-historic brickwork, subject to approval by the
University Project Manager.
The Contractor shall prevent infiltration through masonry or masonry openings during
masonry cleaning. Special care shall be taken with very old masonry on historic
buildings. All work must be approved by the University Architect.
Sandblasting of masonry is prohibited.
Cleaning of masonry is prohibited within 48 hours of construction.
04510 MASONRY REPAIR
All masonry construction and repair on historic structures shall be accomplished only
upon the advice and direction of the University Architect.
Careful attention must be given to the specification of proper mortar mix and color range
in the repair of mortar for historic buildings. The determination of mortar content shall
include laboratory analysis of mortar samples followed by special mixing of granular
content.
Where the original mortar was not pigmented, no pigments shall be used in the new
mortar to attempt a color match. The granular content usually provided the coloration in
nonpigmented older mortars.
Where the original mortar was a lime and sand mortar without cement, cement shall not
be used in the new mortar. High-cement-content mortars are prohibited as replacement
mortars in historic buildings at the University, except where an older building was
originally constructed with precisely such mortar. The University prefers to replace failed
mortar joints rather than damaged bricks or stone units.
For all historic structures, mortar joint removal techniques and new mortar joint profiles
are critical. Removal of failed mortar, if possible, must be accomplished gently so that
bricks or stone are not damaged. Hand chiseling is the only acceptable removal technique.
Air hammers and masonry saws are prohibited.
P.4-6
December 1998
DESIGN AND CONSTRUCTION STANDARDS
FACILITIES MANAGEMENT SERVICES
DIVISION 4
MASONRY
Along with mortar content, mortar color and masonry unit type, pointing techniques must
be presented in advance in sample panels no smaller than 2 ft x 2 ft, located at the
building site (or transportable to the site) for approval by the University Architect.
The Design Consultant shall specify “low salt” mortar and brick and assure that the best
workmanship standards of the trade are used in an effort to prevent efflorescence. The
Contractor shall remove efflorescence and correct the work as necessary to avoid further
efflorescence.
Where repair of masonry is undertaken, the wall surface shall be covered with damp
burlap and kept damp for at least one week after repairs have been made.
Glazed terra cotta repair or replacement shall be evaluated by the University case by case.
December 1998
P. 4-7