Information on Reinforcement Spacing in Gunite and Shotcrete Swimming Pool Construction For Prospective Pool Purchasers

The purpose of this article is to clear up any confusion resulting from sales claims about the benefits of closer spacing of reinforcement in gunite and shotcrete swimming pool construction.

Often swimming pool sales personal provide confusing information on this topic.

When comparing proposals from different swimming pool construction companies, homeowners may become confused about the real benefit of claims about larger or more reinforcement being proposed for their pool.

It is not uncommon for pool sales people, as a part of the selling process, to claim that less spacing between the reinforcing bars (for example 10 inches apart vs. the traditional and well proven 12 inches apart) results in a stronger swimming pool structure. The obvious goal of these sales claims is to create the erroneous illusion that the pool being sold is a better value because of this small decrease in the reinforcement spacing.

Decreased reinforcement spacing results in an increase in the amount of reinforcement. However, to receive the potential benefit from an increase in reinforcement, it is also necessary to increase the gunite or shotcrete thickness. Without also increasing the thickness of the gunite or shotcrete, the benefit from minor additional reinforcement is, in my opinion, negligible.

Based on my many years of experience as an engineer specializing in the structural design of swimming pools, it is my recommendation that the bond beam of the pool should be the 1st priority for additional reinforcement. It is my opinion that installing four(4) #4 reinforcing bars in the bond beam offers greater potential benefit then a minor decrease in overall reinforcement spacing. Obviously, any unusual site-specific ground conditions should be addressed by a professionally licensed engineer experienced in swimming pool structural design.

Hundreds of thousands of swimming pools have been constructed over the years with the traditional rebar size spacing with well-proven durability. Far more important then adding an insignificant amount reinforcement is the financial strength, experience, size, and years in business of the company providing the warrantee. Hopefully this information clarifies the issue of reinforcement spacing in gunite and shotcrete swimming pool construction.

Ronald Lacher, P.E.