We have been in the gunite/shotcrete business since 1978, with a commitment to quality. Originally, North County Gunite performed the majority of it's work using gunite. Which as described in the Gunite vs. Shotcrete page is a mixture of sand and cement pushed through a hose dry, mixing with water at the nozzle tip. A small percentage of the work performed (25%) was with shotcrete. The shotcrete work was, at the time used mostly for jobs requiring a guaranteed psi of 3,000 and above. Gunite was used in swimming pool construction and ditch linings where 2,000 psi was all that was required.
In November of 1998 North County Gunite switched 100% of its operations to shotcrete due to the inability to consistently achieve 2,000 psi with gunite. Problems with structural cracks from an inconsistent mix and delaminations in pool walls needed to be addressed. We tested different types of sand by shooting test panels that were sent to labs to determine the compressive strength that was reached. Few test produced the 2,000 psi that we required in our swimming pool construction. Even had the test produced 2,000 psi there was still a problem to confront, soil. Soil plays a big part in a structurally sound-built pool. Pools built in decomposed granite (DG) would most likely do well, even with gunite and it's 2,000 psi, but unfortunately most of San Diego and surrounding counties aren't composed of DG. Expansive clay type soil is the norm in 50% of San Diego and with gunite your taking a risk of structure problems that wouldn't be an issue with shotcrete.
With all the testing and information gathered from it, the decision was made to change North County Gunite's operation completely over to shotcrete. This was a huge undertaking for the new North County Gunite & Shotcrete. There was a lot of work to be done, re-training of our crews together with the replacement of four full sets of gunite equipment with shotcrete pumps and various support equipment was definitely a challenge. All of us at North County Gunite & Shotcrete, owners, management and staff, are pleased with the results of the change, we have absolutely no regrets. As to date there have been no delaminations or similar problems. All the testing done on shotcrete placed by us has achieved between 3,000 to 4,000 psi, quite an improvement from our previous testing on gunite. The end result has been a consistently superior product.