Steel Reinforcement & Bonding

Steel Reinforcement & Bonding in Pool Construction: Rebar, Grounding & Structural Strength

In North Texas pool construction, steel rebar is installed immediately after excavation to form a structural grid within the pool shell. This is especially crucial for concrete pool designs. This rebar cage must be carefully shaped to match the engineered layout, supported above the soil with “chairs,” and bonded correctly for electrical safety. The steel reinforcement gives the gunite shell its strength, helping it resist shifting soils, hydrostatic pressure, and long-term wear. Due to the expansive clay and shifting soil common in North Texas, precise steel placement and proper bonding are vital. Errors during this phase can lead to major structural issues like cracks or shell failure.

Smart Starts

  • Verify Steel Size & Spacing: Check that the rebar being used matches the engineering plans. At Radelli Designs we exceed the standard and require a minimum use #4 rebar (1/2″) Grade 60 as specified, Placed at a minimum of 10” on center. In areas where expanisve soil is common, such as areas around Lake Lewisville, Lake Grapevine or any major bodies of water we often default to what is called a double mat rebar cage. This refers to a concrete reinforcement system using two layers of steel rebar. Bars should be laid out in a grid or contour pattern with consistent spacing on both horizontal and vertical, depending on engineering). Improper spacing (too far apart) creates weak spots , while too close can hinder concrete flow . No area should look like an unsupported span of more than 10” without steel. If you see extremely large gaps or if the steel looks thinner than expected, question it.

  • Proper Support & Clearance: All rebar must be secured in place and lifted off the soil. Look for plastic “chairs” or spacers holding the steel cage a few inches above the ground and away from the dirt walls. This ensures the steel will end up embedded in concrete with sufficient coverage. The rule of thumb is 3″ of concrete cover over any soil-facing rebar, no steel should touch earth or it will rust through the gunite. Also, any plumbing pipes running under or through the steel should not be directly against soil without protection. Common mistakes include rebar sitting on dirt (leading to inadequate coverage) or using rocks/chunks of concrete as chairs instead of proper supports (unstable and can shift).

  • Shape and Elevations: Walk around and compare the steel shape to your design. Steps, benches, spa, and other features should be clearly formed by the steel outlines. For example, a spa should have a cage, benches will have horizontal steel mats, and a deep end hopper should be defined. Check pool depth by measuring from the top of steel to the bottom – account for about 6” of gunite that will cover the steel (e.g., if you wanted a 4’ deep shallow end water depth, the steel might be around 4’6” below the intended water line, since gunite+plaster add thickness). If something looks off (say, a bench too low/high or a slope not as expected), bring it up before gunite. Adjustments can be made by re-tying steel now; after concrete, it’s too late.

  • Electrical Bonding Grid: Bonding is a critical safety system that equalizes electrical potential to prevent shocks. You should see a bare copper wire (usually #8 AWG solid) clamped onto the rebar in at least four places around the pool . In North Texas, code typically requires four equally spaced bond connections to the steel cage, plus bonding of any metal within 5 feet of the water (ladders, diving board anchors, light niches, etc.) . Ensure that features like spa steel, any waterfall rebar, or a slide’s steel base are also tied into this bonding wire. All bond wire connections should be tight with approved clamps (usually brass). This bond wire will eventually connect to the pool equipment and bonding lugs, creating a loop around the pool. Do not skip bonding – an unbonded pool can be extremely dangerous (and will definitely fail inspection).

  • Grounding vs. Bonding: Note the difference: bonding (described above) ties all metal together around the pool. Grounding is electrical – the pool light niche and equipment will be grounded via the electrical system. Ensure the rebar cage itself isn’t mistakenly used as a ground rod – it should only connect to the bond system. At this stage, you might see a green insulated ground wire run to any junction boxes or light niches, which is good.

  • Main Drains & Inserts: The steel crew often ties the main drain housings in place at the bottom of the deep end (if not set earlier). They should be secured so they won’t move when concrete is sprayed. Also, any other fittings that penetrate the gunite (like returns, spa jets, light niches, skimmer throats) should be positioned. Confirm that skimmers are set in the correct locations (usually at the waterline of the pool’s perimeter) and that they are braced to the form so they stay put during gunite. If you have a raised spa or raised wall, its plumbing (e.g., spa jets, waterfall pipes) should be roughed in now and tied to steel as well.

Inspection checkpoint:

Before gunite is applied, both a city inspection and a homeowner inspection are essential. The municipal inspector will perform what's commonly referred to as a "belly steel" inspection, checking for proper rebar size, spacing, 3" clearance, correct bonding connections, and that all plumbing lines have passed pressure testing. However, don’t rely on this alone, take the time to do your own inspection. No gunite should be applied until the structure fully passes and any necessary corrections are made. For expert advice on pre-gunite steel inspections or full project consulting, Radelli Designs offers professional guidance and consulting for North Texas Home Owners throughout every stage of your pool build!