December 1, 2008 at 4:40 pm #175898Matthew E WilsonParticipant
Reasons for cast rock
There are many reasons for cast rocks popularity increasing over the years. Some examples of why to utilize cast rock are; speed of installation, site access for equipment and personnel, believability, minimal skills.
Speed of installation is the primary reason contractors, municipalities, hotel resorts, and homeowners choose to utilize cast rock. There is simply nothing faster to install that can look more real than an exact copy of a rock cast from a mold of the real thing.
Many building sites these days, given the high price of land, force developers to cram more and more buildings into a given space. This creates problems for site accessibility. Many sites have nothing more that 5-10 feet between properties making the import of large real boulders almost impossible. Without the use of high reach equipment or cranes, many projects would have to compromise design because of limits for materials and equipment.
With the use of cast rocks, the only space required needs to be large enough to fit a technician and gfrc castings of rock through the opening. This is particularly true in an aquarium, animal exhibit, or indoor landscaping.
Site conditions could be anything that would prove problematic for real rock. For example how would you go about adding boulders to the side of an existing swimming pool remodeling project? You couldn’t even consider it with real rock. Utilizing gfrc rock castings instead would be a matter of dowelling into the side of the existing gunited pool shell. You could even use your existing pool plaster and tile as the waterproofing membrane behind the artificial rock. After completion of the rock work installation, just replaster and you will successfully recreated a dramatically different look for the exiting environment.
How about a hillside or roof top location? How would you secure a giant grouping of boulders to a hillside location? Footings? Piers? In earthquake country like Northern California? Probably a more realistic approach would be to compromise your design and eliminate the natural boulder look altogether. Another option would be to utilize gfrc rock castings reassembled on an engineered footing to create a permanent rock outcropping without the liability that it might roll down the hill someday.
Just how strong is artificial rock? Ridiculously strong. With an engineered concrete foundation and 7,000+ psi gfrc rock castings with a sub structure of rebar and grout in-filled, the strength and durability will outlast most building foundations and could carry the weight of a semi-truck.
The issue of size is another very important topic. Size is the reason for cast rock. A crane and crew can only lift and carry a massive boulder so far. With cast rock panels there are absolutely no limits on size or shape other than engineering or budget limits. When was the last time you tried to waterproof around or under a giant real boulder? Utilizing the cast rock method of fabrication, the rebar dowel penetrations are the only critical areas to protect and are always in plain site until grouted solid. This essentially eliminates any guess work as to whether there are any waterproofing failures.
“Only after the last tree has been cut down,
Only after the last river has been poisoned,
Only after the last fish has been caught,
Only then will you realize that money cannot be eaten”
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