The basics of artificial rocks

Recently published in Colorado Green by Karen Van Heukelem of di Giacomo, Inc, this article has some good tips on what sets di Giacomo rocks apart from the typical “fake rocks” found today:

At di Giacomo, we have a simple recommendation: when you are able to use real rocks, use real rocks. However, circumstances arise when real rocks cannot achieve the desired results. Man-made concrete rocks, despite their less-than-stellar “fake rock” reputation, have the potential to create an aesthetic solution. There are three overlying rules to working with fake rocks: look to nature, think creatively, practice social responsibility.

Look To Nature

Rocks should compliment good design in landscapes. At di Giacomo we understand and continuously study the dynamics of nature. Nature moves and is always changing. So when designing a rock formation, we understand the formation must create a motion picture, not a still shot. The rift, grain, hard grain, talus, and color of rock formations need to be understood and implemented.

Planters need to emerge from the rift crack in a formation, not a hole punched in the concrete where someone decided a plant would “look nice”. The rift crack holds the most soil and moisture where trees and plants naturally germinate.

Talus, pieces of rock which broke away from the mass of the feature at some point in time, is also a crucial element to the design. Without talus, a rock formation misses some of the story.

Without proper coloring, a rock feature will not look correct. Coloration isn’t about what colors match, but about reproducing the effects of weathering. Typically in Colorado, when we see rust colors in a rock, we are seeing minerals leaching out of the rock. The darker streaks we see on rocks are mineral deposits staining the surface through condensation. The true color of a rock is only seen at a fresh break in the rock. By understanding how rocks weather, one can color a rock correctly. It’s an antiquing process more than a painting process.

Think Creatively

The process di Giacomo uses in creating rocks differs from many companies. First, we don’t bid work. Quality rock work will not materialize if contractors are pricing projects too low to take the time to pay attention to the details, both in the design and construction process. Creating rocks is an art and needs to be treated as such.

Second, we begin at the early stages of the project. We work with the landscape architects, learn about their vision for the project, and get to know the audience. In the early design phases, we construct a maquette, a precisely scaled model that serves several purposes. The maquette allows the landscape architect and owner to see the feature prior to any construction. It also provides a map for our artisans to create the rocks during construction, precisely following the rules of nature as they apply specifically to a site.

Be Socially Responsible

The maquette allows for the artisans at di Giacomo to think through the site and the audience. Through the creation of the maquette, we implement elements of social responsibility into the design. For example, in playgrounds, we ensure clear visibility for the caregivers to their children, while creating spaces that encourage imagination and a connection to nature for the children. In every design, our goal is to create spaces that inspire, encourage positive human interaction, and encourage a respect and understanding for nature.

Once the maquette is approved, we begin manufacturing the rocks. At di Giacomo, we use glass fiber reinforced concrete (GFRC) panels. The panels themselves are about ¾” thick and typically backfilled with either concrete or foam once on site. From our own collection of molds taken from nature we cast and construct the panels to match the maquette. These are then cured, shipped and assembled on-site, colored and sealed. Through time, the rocks melt into the landscape and carry on their own story, continuing the motion picture of nature.



di Giacomo rockwork at a private residence