Our Process

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At Nitterhouse Masonry Products, We take pride in every single block, paver, and stone we produce. We always make sure all of our products are manufactured to the highest standards and the best possible quality.

Making Concrete Block at Nitterhouse Masonry

The process of making a concrete masonry unit (CMU) hasn’t changed much since its inception in the early 1900’s. Raw materials are mixed with water, formed into a mold and left to cure for a period of time. The basic process is simple, but with advancements in the industry over the years, CMU manufacturing has become a science of chemical engineering and architectural integrity.

From our beginnings in 1923 as Nitterhouse Concrete Products to the family of concrete and stone companies that is Nitterhouse today, we’ve created better systems for increased production, quality control, process monitoring and a vast array of architectural concrete products. Our CMU process uses the best of technology and equipment, managed and monitored by a dedicated team that takes pride in every block we produce.


There are generally just two types of materials needed to form concrete block: aggregates and cements. The aggregates such as sand and crushed stone form the main structure of the block. The cement acts as the binder that holds the aggregates together and solidifies the block when it’s mixed with water.

The sand, stone and cement are delivered to our plants in large-volume dump trucks from local quarries. The aggregates are stored in open air storage bins in our yard. Since the cement is sensitive to moisture, it is blown into our cement silos. We have various types and sizes of aggregates and cements to produce our diverse line of architectural concrete block.

Every concrete block unit will contain the following materials in different quantities and variations depending on which type of architectural block we’re running on the production line:


The Manufacturing Process 

In comparison to concrete mixtures used for general construction purposes, a concrete block mixture will have a higher ratio of sand to gravel and water. This produces a dry, stiff mixture with high compressive strength that holds its shape when it is removed from the block mold.

The materials that are needed for the day are scooped up in the yard by a front-end loader and dumped to enclosed compartments connected to the production line. Our machine operator selects the amount of raw materials needed for the batch being produced on our computerized system, which precisely measures and releases the material to make the type of block we’re running.

Here’s how the process goes:  

Concrete being made on a conveyer belt.
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The pallets are then moved to carts which travel into our low-pressure steam kiln to be heated. Generally, the rack of concrete block is preset in the kiln at normal humidity and temperatures (70 to 100 degrees Fahrenheit) for up to three hours. Then the steam is gradually introduced to the kiln, and the temperature is slowly increased to the appropriate level.

When the top temperature is reached, the steam and heat are shut off, and the blocks cure for another 12 to 18 hours in the hot, moist air. Then the moist air is exhausted out of the kiln, and the temperature is raised to completely dry the block.

A block typically cures for 16-24 hours at high humidity and an average temperature of approximately 100 degrees Fahrenheit.

Nitterhouse Plant Production

The Many Faces of Architectural Concrete Block

At Nitterhouse Masonry Products, we take pride in every single block, paver and stone we produce. We always make sure all of our products are manufactured to the highest standards and the best possible quality. Our line of architectural concrete block includes a variety of options with textured looks or smooth veneer finishes and various colors, shapes and sizes to provide design professionals with a wide range of options in concrete masonry construction.

Whether you need the basic concrete block for a rush job, have an architectural specialty to build or need a specific look for an elaborate office building, we can produce the block you need. Get familiar with each concrete block unit to know all that’s available for your next construction project:

  • Ground Face Finish. Our Ground Face CMU is ground on at least one side, giving it a smooth, rich finish. With 20 standard colors, you’ll have plenty of options for combining colors, but we can also customize the pigment for your designing requirements. 
  • Split Face Finish. This textured block comes in the standard Split Face finish, Split Wide Profile and Split Fluted to satisfy a wide range of architectural looks. The depth and dimension of this design is a favorite for a variety of interior and exterior building projects and, like many of our CMU’s, can be used at or below grade.
  • Antique Finish. Our Antique CMU is finished with a shot blast that beautifully exposes the stone beneath. We have several standard colors, and if they don’t suit your needs, we can customize the color just for your project. This block provides a fine, weathered look with a rustic texture that is used for both interior and exterior building. 
  • Monarch Traditional. You get the look of clay brick with the quality of a block in our Monarch Traditional line. These CMU’s are the length and depth of a regular block but the height of a standard brick. You can use this block at and below grade. We have designed them to meet ASTM-C90 standards for load-bearing concrete masonry. 
  • Elite CMU. No need to lay block and then face it with ceramic tile for interior applications. Our Elite CMU is an outstanding building material for both interior and exterior excellence. With color choices like salmon and gun metal, these filled and polished blocks are ideal for large commercial projects such as schools or municipal buildings needing that touch of color and style. Faces are ground and then filled with an acrylic resin filler. After polishing, they are sealed with our Volatile Organic Compounds (VOC) compliant sealer. 
  • Recycled CMU. Our “Eco-Smart” Recycled CMU is produced in our ground face and split face design. With a minimum of 30% recycled material, this is the popular choice for your environmentally-focused project. The recycled content will contribute LEED (Leadership in Energy and Environmental Design) points for your sustainable endeavor. 
  • Legacy Stone. Our Legacy Stone is an architectural veneer block that shows off the aggregate content of the block. It’s manufactured with a strength of 8500 psi and less than 5% absorption. We have four different finishes in our Legacy line which are often intermixed in a single project for visual appeal and structure:
    • Linear Collection – two finishes on one block: ground face and shot blast. The width of each band is customizable to fit unique designs, and there are deep scored lines between the two different finishes.
    • Textured – finished with a shot-blasted face, giving slight texture and dimension.
    • Terrazzo – finished with a ground face, smooth and polished defines this concrete block unit. It’s often used for banding stripes.
    • Chiseled Face – finished to resemble the look of cut limestone, these stones are often used for accent bands to break up large sections of one color and texture. 

Select your desired block in a variety of specialized shapes for specific construction applications. We manufacture special forms of concrete block for construction of bond beams, control joints, radiused corners and many other architectural plans.

All Nitterhouse architectural CMU’s are sealed with a VOC-compliant, water-based acrylic resin sealer and should be coated with another sealing treatment when masonry work is complete. We also add a water repellent admixture to all our concrete block batches to reduce absorption and permeability. We provide this admixture to be added to the mortar when laying the masonry walls.

Architectural block on skids.