Mesastone® ASTM Reports

Trenwyth / Mesastone

Mesastone® Specification


Part 1 General

Submit color samples for selection from manufacturer’s group A, B, C, D or E. Submit product literature, certifications, test reports and full size sample(s) of each color specified.

Quality Assurance
Certifications: Concrete blocks for finishing shall conform to ASTM C90. All units contain a manufacturer-approved integral water-repellent CMU admixture at the time of manufacture.

Fire Resistance: Define hourly ratings required by NCMA TEK Notes.

Field Constructed Mock-Ups: Construct a sample panel, no less than 4′ x 4′, of each color and size units to be used in the project.

A full size unit is required to illustrate color and texture for approval. Manufacturer requires a sample panel be installed at the jobsite prior to installation. This panel will represent both the quality of the product and the workmanship to be expected for the project. The panel must be approved by either the owner or architect for the project. Manufacturer will provide 4″ units for a 4′ by 4′ sample panel at no cost for the material (excluding freight to site).

Delivery, Storage and Handling
Verastone Textured and Mesastone units shall be delivered to the jobsite on covered banded pallets with cardboard between layers. Store pallets in single stacks on level ground and cover with waterproof covering (e.g., tarpaulins) to protect the blocks from inclement weather. Handle blocks carefully to avoid breakage and damage to the finished surfaces.

Project/Site Conditions
Protection of Work: Cover walls each day after installation to keep open walls protected and dry. After units are installed they should be protected from damage by other trades performing operations that can stain or otherwise damage the finished surfaces by covering walls with plastic. Corners should be protected from damage after installation by covering them with plywood.

Part 2 Products

Product Name
Verastone® Textured recycled concrete masonry units
Mesastone® textured concrete masonry units


Northfield Block Company (800) 358-3003
3400 E. Bungalow Road, Morris, IL 60450

Related Materials
Colored matching or contrasting mortar is available from manufacturer. Consult NCMA TEK Notes, for mortar type and specifications. For all exterior mortar, use matching manufacturer-approved water-repellent mortar additive, following manufacturer’s instructions. Consult manufacturer for recommendations.

Sizes and Shapes
Nominal 2″, 4″, 6″, 8″, 10″ and 12″ standard block thickness are available as well as all standard block shapes. High-strength units for special structural requirements, over-sized units, and metric shapes and sizes are also available.

Masonry Cleaners
Carefully following manufacturer’s instructions, use Burnished Custom Masonry Cleaner by PROSOCO (dilute 1 part to 3 parts clean water). Available from manufacturer. Do not powerwash.

CAUTION! Never use Muriatic Acid solution or any cleaner containing acid on units.

Part 3 Execution

Laying Masonry Walls
Draw blocks from more than one pallet at a time during installation. All exterior mortar shall include matching water-repellent additive added to each batch in the appropriate dosage rates for mortar type (M, S or N) per manufacturer’s instructions. Refer to NCMA TEK Notes, for Hot and Cold weather construction practices.

Lay units using the best concrete masonry practices. Install only quality units; reject all defective units as defined by ASTM C90. Lay blocks with the faces level, plumb and true to the line strung horizontally at the finished face. Units shall have uniform, 3/8″-wide joints both horizontally and vertically on the finished side of the wall. Tool joints neatly after they are finger-hard to make them straight and uniform. Size and place cut pieces appropriately to maintain consistency and bond. Complete masonry construction using procedures and workmanship consistent with the best masonry practices.

Lighting: Provide adequate lighting for masonry work by placing all lighting at a reasonable distance from the wall for even illumination. Do not use trough lighting.

Cutting: Make all unit cuts, including those for bonding, holes, boxes, etc., with motor-driven masonry saws, using either an abrasive or diamond blade. Cut neatly and locate for best appearance.

Mortar Bedding and Jointing

  1. Lay units with full mortar coverage on head and bed joints taking care not to block cores to be grouted or filled with masonry insulation.
  2. Tool all mortar joints when thumbprint hard into a concave configuration.
  3. Care should be taken to remove mortar from the face of masonry units before it sets.
  4. Tuckpoint the joints of scored units for proper appearance. All exterior scored units must be tuckpointed to prevent water penetration. NO RAKE JOINTS.

Flashing of Masonry Work
Install flashing at locations shown in the plans and in strict accordance with the details and the best masonry flashing practices.

Weep Holes and Vents
Install weep holes and vents at proper intervals at courses above grade and at any water stops over windows, doors and beams. Consult NCMA TEK Notes, for additional flashing information.

The textured faces shall conform to the requirements of ASTM C90 when viewed from a distance of twenty (20) feet at right angles to the wall with normal lighting.

Keep walls clean daily during installation using brushes. Do not allow excess mortar lumps or smears to harden on the finished surfaces. Harsh cleaning methods after walls have been erected may mar the surface of the blocks.

Final Cleandown
Clean the completed walls with PROSOCO Burnished Custom Masonry Cleaner (dilute 1 part to 3 parts clean water), strictly following the manufacturer’s instructions including thorough rinsing. Do not use acid or abrasives on the finished surfaces. Failure to strictly follow manufacturer’s instructions can result in permanent damage to the finished faces. Do not powerwash.

High-pressure power washing may interfere with the performance of the integral water-repellent additives and cause efflorescence. (Maximum psi is 50.)

Verastone Textured and Mesastone units, properly installed and cleaned, need virtually no maintenance other than routine cleaning. For tough stains, contact manufacturer for specific cleaning recommendations.

Installation Recommendations
Consult NCMA TEK Notes, for proper installation of concrete masonry units.


  • The facing is not intended for use as an impervious surface.
  • Acid solutions and HCL acid-based cleaners should not be used as a cleaning agent or in direct contact with the facing