NRG Insulated Masonry Units

Architectural Masonry / NRG Insulated Masonry Units

NRG Specification

Specification – NRG Details: PDF - NRG Details: MS Word – Composite Diagram: PDF

Part 1 — General

Submit color samples for selection from manufacturer's groups Traditional, Classic and Premium. Submit product literature, certifications, test reports and sample(s) of each color specified.

Certifications: All NRG. Insulated Concrete Masonry Units will meet or exceed ASTM C-90, normal weight classification.

Material: All insulated, web-less, concrete masonry units shall be NRG ICMU’s, (Insulated Concrete Masonry Units) except corner, half, solid bottom bond beam and sash units. These special units shall be conventional units and shall interspersed into the NRG wall construction where needed. Incorporation of conventional CMU’s into the NRG wall system will have no adverse effect upon thermal performance of the overall system. NRG ICMU’s are available from manufacturers licensed by Niagara Regional Group, Ltd. ICMU’s shall be specified as lightweight, medium weight, or normal weight NRG design units. All units contain a manufacturer-approved integral water-repellent CMU admixture at the time of manufacture. The NRGâ"¢ ICMU’s are available in Split Face, Marble Face, Marble Face Polished, Weathered Face and Gray block. Check with local suppliers for availability. All Masonry Units must contain an integral Expanded Polystyrene Insert installed at the site of production.

All Masonry Units must contain a Dovetail design to lock the insulation and inner and outer module together. All Masonry Units must not contain a thermal bridge from face to back where as sound, moisture, and thermal energy can be conducted through the wall.

General Conditions
Part I: It is important to note that the NRGâ"¢ ICMU (Insulated Concrete Masonry Unit) is designed with an off-centered core configuration. Therefore, the vertical rebar (positioned and set in the poured foundation) must be matched to the same off-centered designation. (According to specific size units the position of the vertical rebar will vary.) i.e.: 12" ICMU offset is 2.5"

Part II: List the requirements for mortar, reinforcing, concrete block work and other associated work and details that relate to this product. If this information is detailed in another section, it should be cross-referenced under this heading. The NRG Insulated Wall System is laid similar to any other block, either in a running bond or stacked bond. (To insure that the thermal mass of the unit is on the inside, face shell and thumb holes toward the outside exterior of the wall.)

Note: This will also insure that the wall is laid with the tightest thermal barrier.
Scope: Interior and exterior walls shall be insulated, web-less, concrete masonry units as shown on the plans/ or indicated on the finish schedule.

Fire Resistance: Fire rated for up to 4 hours. Define hourly ratings required by NCMA TEK Notes, available at

Field Constructed Mock-ups: Construct a sample panel, no less than 4'x4', of units of each color and size to be used in the project. (These units need not be NRG ICMUs).

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 of any Oldcastle masonry product. 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).

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.

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.

NRG Insulated units are manufactured by:
Anchor an Oldcastle Company (732) 292-2674
975 Burnt Tavern Road, Brick NJ 08724

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

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

Face Sizes: Modular 8′x 16″

Face Mortar Joints: 3\8″ exposed.

Shapes: Shapes not available in the NRG design shall be substituted for using conventional hollow core CMU’s matching the same finish and color of the NRG units.

Scoring: The NRG block cannot be scored.

MASONRY CLEANERS Carefully following manufacturer's instructions, using appropriate Masonry Cleaner by PROSOCO.Do not powerwash.

CAUTION! Never use Muriatic Acid solution or any cleaner with an acid base on units.

Part 2 — Products



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: All cuts for bonding, boxes, holes, etc. shall be made using a motor driven masonry saw using either an abrasive or diamond blade.

Note:The NRG unit should not be cut in half.


  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.


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


The 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, rags and the burlap squares supplied on the pallets. Do not allow excess mortar lumps or smears to harden on the finished surfaces. Harsh cleaning methods after walls have been erected will mar the surface of the blocks.


Clean the completed walls with appropriate PROSOCO Masonry Cleaner, 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 apply Masonry Cleaner with pressure spray above 50 psi. Do not powerwash.


Properly installed and cleaned, units need virtually no maintenance other than routine cleaning. Contact manufacturer for specific cleaning recommendations.

Consult NCMA TEK Notes, available at, for proper installation of concrete masonry units.