CMU Product Specifications:

Part 1 General

    1. Related Documents:  ACI530.1/ASCE6/TMS602 Standard Specifications for Masonry Structures.

1.2 Summary

  1. Related Sections include the following:
    1. Division 7 – “Dampproofing” for dampproofing applied to the face of backup wythes of cavity walls.
    2. Division 7 – “Water Repellents” for water repellents applied to unit masonry assemblies.
    3. Division 7 – “Sheet Metal Flashing and Trim” for sheet metal flashing.
    4. Division 7  - “Joint Sealants” for sealing control and expansion joints in unit masonry.

1.4 Performance Requirements:

  1. Determine net-area compressive strength (f’m) of masonry from average net area compressive strengths of masonry units and mortar types according to Tables 1 & 2 in ACI 530.1/ASCE6/TMS602.

1.5 Submittals:

    1. Samples for Verification:
  1. Decorative concrete masonry units for color and texture
  2. Standard concrete masonry units for texture
  3. Colored mortar
  4. Weepholes / Vents
  5. Test reports for concrete masonry units.
  6. Mortar proportions according to ASTM C-270
  7. Mortar Additives.
    1. Sample Panels:  Build sample panels to verify selections made under sample submittals and to demonstrate aesthetic effects.   Leave sample panel in place until masonry construction is accepted by owner.  Sample panel should be utilized to demonstrate cleaning procedure to be used on finished masonry construction.
    2. Deliver, Storage & Handling:  Store masonry units on level surface to prevent chipping. 

Part 2 Products:

A.  Concrete Masonry Units (CMU): Standard Units – As manufactured by a Midwest Products Group Company.

  1. Comply with ASTM C-90. 
    1. Minimum Compressive Strength (units with higher unit strength must be specified. Please contact a sales representative to discuss)
      1. Lightweight – 2500 psi.
      2. Normal weight – 3500 psi
    2. Weight Classification
      1. Lightweight – less than 105 lbs / cubic ft.
      2. Normal weight – greater than 125 lbs./ cubic ft.
    3. Provide sizes and shapes indicated on drawings.
    4. (Special Features May Be Noted Here.  )

B.  Architectural Concrete Masonry Units (ACMU) – Manufactured by a Midwest Products Group Company.

  1. Comply with ASTM C-90
    1. Minimum Compressive Strength – 3500 psi
    2. Absorption Less than 9% of unit weight.
    3. Style / Texture – (Specify) Splitface / Fluted / Scored etc.
    4. Color – (Specify)
  2. When Specified, All units shall contain Rheopel admixture to reduce water absorption.  Mortar admixture should also be added to all mortar used to install with these units.  Single wythe walls should also receive a field coat of Prosoco “Custom Masonry Sealer” as part of the overall water repellent strategy.  Veneer systems and Cavity walls do not require the field-applied sealer.

C.  Other Items as required by the Masonry Code:

  1. Mortar Materials – Specify Type (M,S,N, or O)
  2. Reinforcement and Metal accessories
  3. Joint Fillers / Movement Joints
  4. Masonry Cleaners – (Midwest Products group recommends Prosoco’s Custom Masonry Cleaner for all CMU & ACMU materials)
  5. Grout Proportioning and Mixing
  6. Insulation – 

Part 3 – Execution

3.1 - Installation, General

  1. Comply with construction tolerances in ACI 530.1/ASCE 6/ TMS 602.
  2. Bond Pattern for Exposed Masonry shall be “Running Bond” unless otherwise noted.
  3. Lay units with “Face Shell” mortar bedding.  Ensure all vertical head joints are well filled.  Tool all mortar joints when mortar is “Thumb print hard” 
  4. Install movement joints as noted on drawings.  In general assume that movement joints should be placed at 1) Changes in wall heights. 2) Over one side of an opening if less than 6 feet wide.  3) Over both sides of an opening in over 6 feet wide. 4) Within 6 feet of all corners and 5) Intersecting walls.
  5. Cover walls at end of day to prevent moisture from entering masonry core or cavity.
  6. Flashing and Weep vents shall be installed at base of wall, above all openings, and any place the vertical flow of moisture will be interrupted.  Extend flashing out beyond the face of the wall, or use a stainless steel drip to ensure moisture is diverted out of the masonry cavity.  Weep vents should be placed at a minimum of 24” o.c.
  7. Cleaning.  Strictly follow the manufacturers instructions.  Always prewet the wall before applying the cleaner.  Use a low pressure pump-up type sprayer to apply the cleaner to the wall.  Overlap cleaning sections to avoid inconsistent results.  Perform test on sample wall before cleaning on finished structure.  Cleaning should not begin until wall has cured a minimum of seven days. 
     
   
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