What concrete cladding solution is right for your project?

Written by Drew Amorin – 9 min Read

CAAST,Opus Pro

Concrete is an important building product for many applications, being the most used of all products made by humans on this planet. That is an amazing statistic. It is so very important that we as producers and consumers work together to make concrete more sustainable.

Many of our customers ask us, “What is UHPC and how is it different than GFRC or SCC or HPC or Fibre Cement?” It’s not an easy question to answer because each product is unique, has unique characteristics and composition, resulting in different performance in a variety of applications.

When looking for a cladding solution for your upcoming project the number of options can be overwhelming. Your goal is to meet all the requirements for design, sustainability, durability, and budget.

Fiber Cement Board

Fiber Cement panels are an affordable and practical cladding solution. They are made exactly how they sound: uniform boards made with a mixture of cement, water, sand, and either glass or cellulose fibers. Fiber cement panels are lightweight and thinner compared to other options and can be fabricated onsite by the installer if necessary.

Be it for a residential or industrial project, there are many advantages to using Fiber Cement Panels. The use of fibers in manufacturing adds strength and durability to the panels, and allows the panels to be as thin as 6 mm. The light weight panels are easy to install and can be either face fastened or fastened with concealed fasteners and clips on the back of the panels. Depending on the fiber used in manufacturing, panels can be either non-combustible or have limited combustibility. Most manufacturers have a standard range of colors and textures to choose from, giving the buyer several attractive options. Arguably the most significant advantage is seen in cost. Compared to natural stone, wood and other architectural solutions, Fiber Cement Boards are typically more cost-effective, especially with the factors above considered.

No product is without limitations, so let’s discuss some things to consider before choosing this material for your next project. Fiber cement manufacturers typically have a standard range of products and customizing is not possible unless very large orders are produced. Set colors, panel sizes, thicknesses are the norm. They can’t be molded into shapes, so standard flat panels are your choice. To go beyond standard colors, some manufacturers offer colored coatings where any RAL or NCS color can be supplied. This coating creates a very uniform appearance which may be contrary to the natural variations that give fiber cement it’s beauty.

Because fiber cement panels are very thin, extra care must be taken in the handling and installation as to not damage the product or crack the panels at fastener points during installation. After installation, fibre cement panels have a low resistance to impact.


High Performance Concrete

High-performance concrete (HPC) is concrete that has been designed to be more durable and, if necessary, stronger than conventional concrete. HPC mixtures are composed of essentially the same materials as conventional concrete mixtures, but the proportions are designed, or engineered, to provide the strength and durability needed for the structural and environmental requirements of the project. High-strength concrete is defined as having a specified compressive strength of 8000 psi (55 MPa) or greater. The value of 8000 psi (55 MPa) was selected because it represented a strength level at which special care is required for production and testing of the concrete and at which special structural design requirements may be needed.

High performance concrete is a broad category that includes fibre reinforced concrete, mesh reinforced concrete, as well as in structural applications where it can be reinforced with traditional rebar and mesh designs. It is categorized based on the range of performance in terms of compressive strength.

Its key advantage is its durability. Its limited porosity means that the product is more resistant to deterioration due to free/thaw action and will also be more resistant to damage from salt and chemicals.

Another advantage is that it can be poured into molds of various shapes or calendared in molds with flat or patterned faces or it may be pressed with layers of mesh to create a thin panel with the strength and durability that High Performance Concrete provides.

Glass Fiber Reinforced Concrete ( GFRC )

Glass Fiber Reinforced concrete is a material made by mixing glass fibers into a cement based mix. This allows the material to be formed into different shapes and designs, while remaining thin and structurally sound.

GFRC is a versatile product that allows variability of designs that can be created, while maintaining structural integrity. Experts have developed methods to mimic and replicate appearances of marble, terracotta, slate, and other natural stones. GFRC provides a cost competitive solution and provides a durable finish that is resistant to fire. Another advantage is its reasonable cost relative to other building materials available on the market. GFRC is environmentally friendly and is chemical and fire resistant.

Like all materials, there are limitations to using GFRC the buyer should be aware of. Over time, weather will wear and weaken GFRC; requiring maintenance for cracks and for fading colours, so it’s durability limitations should be considered. GFRC is a labour intensive product to manufacture since the materials are hand sprayed and packed, which sometimes makes the production process very slow.

Cast Stone

Cast stone is a hybrid concrete/stone material that looks most like natural stone. A dry mix of concrete and other aggregates are hand or machine pressed in small panel sizes and thick sections, giving the material a rugged look that replicates the look of natural stone.

Its main advantage is its malleability and ability to mimic natural stone, at a fraction of the cost. This is ideal for adding designs to pillars, doorways, fireplaces, etc. There is no fiber reinforcement in cast stone, causing it to be brittle, and prone to cracking over time.


Ultra-High Performance Concrete

Ultra-High-Performance Concrete (UHPC) is a concrete solution that mixes water, sand, cement, silica fume, and different fibers that allow the material to be thin, while also being extremely strong.

UHPC is special because of its variability, and its ability to be molded into almost any shape while maintaining its structural integrity. This is ideal for more complex architectural projects or “architectural art”. In terms of design, there are an unlimited number of custom colours and textures available, allowing you to achieve almost any look imaginable. This material is most comparable to natural stone in terms of appearance, but is structurally comparable to aluminum because of its density, and stainless steel because of its weather resistance. One of the biggest advantages is its strength; with the ability to withstand 120-280 MPa of compressive pressure, 10-20MPa or more of flexural pressure, and 4-7 MPa of direct tension. In addition to its superior strength, UHPC is extremely durable, and is built to withstand the elements. One example of this is the ability to maintain 95-100% of its structural integrity after 300 cycles of freeze/thaw. UHPC loses very little residue from salt, has low porosity, and is non-combustible, resulting in a product lifespan of roughly 300 years.

The density of UHPC causes it to be quite heavy (approx. 10-13lbs/sqft) which may be seen as some as a disadvantage of this material due to higher cost of installation. Manufacturers typically recommend a complete hanging system with embedded anchors. In some cases UHPC may be more costly than the alternate materials mentioned, however it’s design flexibility and extremely long life span should be taken into consideration.


Key Differences

Fiber Cement Boards are made much like paper, a thick cementitious slurry is compressed and cured between pressure plates to form the panels.

Glass Fiber Reinforced Concrete can be either wet cast or sprayed into molds.

Cast Stone is dry packed into molds. This can be done manually or through a semi or fully automated process.

High Performance Concrete is wet cast into the molds with reinforcement either in layers or throughout the mixture.

Ultra-High Performance Concrete is wet cast into the molds with reinforcement either in layers or throughout the mixture.

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