L&R Landscape recently installed a unique "Zen garden" hardscape for IBM's Tivoli Corporate Campus in Austin. The concept and design came from Ron Slade of Houston-based firm H.O.K., based on classic Zen principles. "The design challenge presented to us was to create a campus as unique as the culture of Tivoli," Slade explained. "The client and user expressed a strong desire to have outdoor spaces where one could bring creative work. 'Zen' was a word that was used to describe the feeling one tenant felt the campus should exude. After digesting these and other user wishes, we began research into the art of Zen and Zen gardening. Zen philosophy is based numerically in numbers divisible by 3. "Zen Buddhists believe the number 3 represents Heaven, Earth, and Man,"Slade said. "The 3 sides of the triangle in our garden reinforce this idea. The large basalt boulders depict the mountains of the Earth, the limestone field represents the oceans and the patron visiting the garden represents Man looking on to the Heavens." The black and white colors represent the positive and negative polarity of the universe. So with all this deeper insight into the world of design concept, we set out to build the project.... Working "Miracles" In the world of commercial construction, as always, the contractor is expected to pull miracles out of his hardhat when it comes to completing a project on time. The IBM project was no exception! In fact they had already set a date for their opening before the landscaping work had begun. To further compound our problems, the building was not finished and our work areas were occupied daily by other trades along with their machines to work on the building, preventing us from breaking ground.This is a common problem on most commercial projects, so we carefully documented our delays and left it up to the general contractor to control the subs. Besides the usual skid loaders and backhoe machines, moving the basalt boulders required a forklift with high ton capacity. Since the biggest boulders were in the 15,000-pound range, it demanded an 8-ton machine. For the smaller boulders, we used a JCB 508c. It gave us the mobility we needed to place the boulders between oak trees that had already been planted. As for the big boulders, we had no choice but to rent the services of United Crane, who brought out a 100-ton crane with an 80-foot boom. It handled the 8-ton stone like it was a pebble. The concrete work in the Zen garden was relatively simple. It consisted of a trough with a 3-inch curb on both sides and a steel divider embedded in the pour to separate the white aggregate from the black aggregates. The plans then called for the black pebbles to be placed in a black mortar bed using an acrylic-bonding agent to bond the embedment mortar to the existing concrete trough. On the other side of the metal divider, we placed white limestone pebbles in a white mortar bed, again using the acrylic-bonding agent to secure adhesion with the mortar and the concrete surface. The technique we used to place the aggregates in the wet mortar was similar to pebble finish concrete. First we sprinkled the rocks in a thick grouping and then used our metal floats to tap the stones into the mortar. Since we were working with an out-of-town architect, we only placed about 5 feet of mock-up to await his approval. This proved to be a good call because he did not like our first attempt. The float method aligned the aggregates in a flat plane and ended up with a relatively smooth surface. Slade explained to us he was looking for a rougher surface. In our next attempt we individually hand-placed each stone into the wet mortar wiggling the rock just enough to have the mortar ooze up and secure the stone in the mortar bed. This was a very time-consuming process and Lisa Schmidt, the President of L & R, even tried her hand at it. While there is something soothing about playing with rocks and wet mortar, we were all relieved when the last pebble was embedded. The architect loved it and said it was exactly what he had envisioned. The interior of the Zen garden was in a very level area on the project, so the designers developed a sub-drainage system to carry away rainwater and prevent flooding. Cutting a trench through the middle and sloping the adjacent areas toward the trench prepared the sub-grade. Then the sub-grade was leveled off with river gravel and covered with a filter fabric material. The finish surface was brought up to grade with 1/4 to 1/2-inch white crushed limestone gravel. Careful coordination was needed to install the electric conduit, irrigation lines to the tree bubblers, and the tree planting. The final feature to build was the Zen sidewalk. First we formed and poured the concrete base of the walk. After selecting a cut Cordova cream limestone for the finish surface, the architect had us cantilever the edge past the concrete to create an irregular edge. When the stone had been laid, we used the black mortar and smaller black aggregates to fill in the middle section. This was easier to install than the border band, since Slade expected it to be a flatter surface. So we were able to use our floats to embed the pebbles into the wet mortar. The finish result was very striking and produced a functional as well as a custom-designed walk. When our hardscape division finishes an installation, we often feel like something is missing. The Zen garden was no exception! The water feature in this project went around the building changing from ponds to streams. Through the Zen garden was a section of stream. The effect of the water running by was nice, but something was missing. It was too quiet! So, we added a wier in the stream to create some water sounds. After the landscape crew installed the plant material and the benches were placed on the Zen sidewalk, the garden was finished. Material Issues In estimating future projects, often times an estimator will come across materials that on first impression blend in with the overall feel of the project, but are impossible to procure in a local market. Black granite boulders and gravel were our challenge on estimating the IBM project. Black & white being the traditional colors associated with the Zen philosophy, we knew that a substitution on the black granite would be hard to come by. Texas is known, especially in the Austin area, for it?EUR??,,????'???s pink or rose-colored granite. The local source in Marble Falls was the quarry that supplied all the stone to construct the state capital and many of the modern state office buildings that surround the capital building. After an extensive search on the internet, we realized to stay with granite we would have to import boulders and gravel from one of the northern states -- that would sink the budget and create time delays, not to mention the danger of buying unseen materials. However, the owner and architect were open to substitutions as long as the color was solid black. After checking a much used resource, ?EUR??,,????'??Roadside Geology of Texas?EUR??,,????'??? by Darwin Spearing, we decided to investigate a quarry in Knippa, a small town about 60 miles west of San Antonio, that was producing a black gravel product. Yes, they had boulders to show us, too. In fact they were using the boulders to crush into gravel, but they reassured me they had plenty of boulders to sell us. So, I set off on a trip to the quarry, one of the joys of my job. Approaching the town of Knippa, I noticed a small line of hills converging on my destination. I later learned from Bob Coble, plant manager of Vulcan Materials Co. that the hills were extinct volcanoes composed of basalt. Vulcan Materials dig and blast boulders from this deposit for their crushing operations. I was immediately impressed with the natural beauty of these stones, but because the architect had been adamant that the color be solid black, I was apprehensive at first that these samples would be accepted. In a dry state the material appeared to be more of a dark gray color than the solid black that Ron Slade had required us to submit. The basalt also had white lines of crystallization inherent from its geological formation. These flaws were later to become appreciated as being a part of the Zen theme. The boulders were sold to L & R at a cost per ton and we used a local trucking outfit to haul the rocks to Austin. Application of a commercial sealer added the sheen and dark color the architect wanted and the owner was duly impressed with the selection. The white limestone gravel was going to be easy, so we thought. After the trouble we had gone through to locate a substitution for the black granite, we knew the white limestone would be available in abundance, since Austin sits on one of the largest deposits of limestone on the planet. Were we in for a surprise when our samples had been approved, and the architect informed us the material we brought in possessed too much color. This was due to the limestone containing other minerals that range from tan and beige to rust. When the gravel is dry, it is chalky and looks totally white, but when it is wet all the subtle coloring becomes more obvious. To solve this problem we had to cull out aggregates that had any color besides white. White limestone boulders were excavated from the site in the early stages of the project and were set aside to supply the landscape contractor with the boulders needed for the finished landscaping. Although these boulders were already approved, they had a lot to be desired in respect to their size and constitution. They were dug from a strata that is closer to caliche than hard limestone, thus making them crumbly and hard to manage. Most of the boulders had to be lifted with straps and then moved to their positions with the extended boom forklift. Some of the smaller boulders we could handle with the skid loader. The white boulders were used on either side of the stream as a border with pocket planting between them.