Steel, Plumbing and Equipment: The Phase You Will Never See Again

May 26

This is the last week anything is visible

After excavation and before gunite, three systems go into your pool: steel, plumbing and equipment.

Then concrete covers all of it, permanently.

You cannot inspect rebar placement through nine inches of gunite. You cannot check a plumbing joint through a concrete deck. Which makes this the phase with the shortest window and the highest consequence, and the one homeowners pay the least attention to because it looks like a mess of metal and pipe.

If you take one thing from this page, take the question at the end of the plumbing section.

Steel

A grid of reinforcing bar, tied together, forms the skeleton of the shell. Gunite is shot around and through it, and the two together do the structural work.

Steel is what allows a concrete shell to handle pressure that is not evenly distributed, which matters more here than in most of the country. The Dallas and Fort Worth area sits largely in the Blackland Prairie, where USDA Natural Resources Conservation Service soil surveys classify the dominant soils as Vertisols, clays defined by their capacity to change volume with moisture. Texas A&M AgriLife Extension research documents this shrink and swell behavior as a defining engineering constraint of building here.

Practically: the sides of an excavation dry and rewet at different rates than the material under the deep end, so different parts of the shell experience different pressure at the same time. The steel is what carries that.

What matters in the execution:

Placement to the engineered plan. Your plans are engineered for your site, and the steel either follows them or it does not.

Coverage. Rebar needs adequate concrete around it on all sides. Steel sitting too close to a surface is a corrosion problem waiting a decade to appear, and by then it is inside your shell.

Ties and continuity. The grid has to act as one structure rather than as loose bars.

More on what our soil does to a pool shell.

Plumbing

Everything that moves water gets roughed in now: returns, drains, skimmers, and lines for any water features, spa or tanning ledge bubblers.

Line routing and sizing affect how the pool actually performs. Circulation determines how evenly water is turned over, which affects chemistry and clarity. Hydraulics affect how hard the pump has to work, which affects what the pool costs to run for the next twenty years. This is a design consideration, not a commodity.

Here is the question to ask, and it is the most useful one in this entire article.

Ask to see the plumbing pressure test.

Every line should be pressure tested before anything covers it. This is not a courtesy, it is the only opportunity to find a fitting problem while fixing it is still cheap. A leak found now is a fitting. The same leak found after decking is poured is a demolition job.

A builder who pressure tests as a matter of routine will be glad you asked. That reaction is itself informative.

Equipment

The equipment pad gets set: circulation, filtration, heating if you have it, and controls for any features.

Two things worth deciding rather than defaulting.

Where the pad goes. It makes noise and it needs access for service. Easier to place well now than to relocate later, and worth thinking about from your neighbor's side of the fence as well as your own.

What the system is, not just what the parts are. Efficiency and performance come from how a pool is plumbed and equipped as a whole, not from which brand appears on a pump. Variable speed pumps, LED lighting and automation all matter, and they matter in combination with the plumbing they are attached to.

Automation is worth a specific mention because it changes ownership more than any other equipment decision. Being able to run the spa or the lights from your phone is the difference between using features and meaning to.

Electrical and bonding

Electrical follows shortly after gunite, running lighting, control systems, pump and motor. One part of it deserves particular attention.

Pool electrical bonding is a life safety system. It connects the metallic components in and around a pool so they sit at the same electrical potential, which prevents a difference in potential from passing current through a swimmer.

It falls under National Electrical Code Article 680 as adopted locally, it is inspected, and it either meets code or it does not. There is no partial credit.

It also has to be complete and inspected before decking covers anything, which is why electrical sits mid sequence in the finishes phase rather than at the end.

What to ask during this phase

Can I see the plumbing pressure test?
Does the steel match the engineered plan, and who verified that?
What inspections happen before gunite, and have they passed?
Where is the equipment pad going, and how loud is it from next door?
Is the electrical bonding inspected before decking?
Can I walk the site and take photographs before gunite?

That last one is genuinely worth doing. Photograph the steel and plumbing layout from several angles before it is covered. It costs you ten minutes and it is the only record you will ever have of what is inside your pool.

Then it gets covered

We target having your pool guniteed by day 7 of construction, so this phase moves quickly. That is deliberate: an open excavation in expansive clay is not something to leave sitting, since walls slough after rain.

Once gunite is shot, everything described on this page is inside the structure. What happens during and after the gunite phase.

Frequently asked questions

Why is the steel and plumbing phase so important?
Because it determines the structural and mechanical integrity of the pool, and because gunite covers all of it permanently. Nothing in this phase can be visually inspected again without breaking concrete, which makes it the phase where quality control has to happen in real time.

Should plumbing be pressure tested before gunite?
Yes, on every line. It is the only point at which a fitting problem can be found while fixing it is inexpensive. Ask to see it, and treat any reluctance as informative.

How much rebar should a pool have?
As specified in your engineered plans, which are drawn for your site rather than to a general rule. What matters as much as quantity is placement and coverage, meaning adequate concrete around the steel on all sides.

What is pool bonding and why does it matter?
Bonding connects the metallic parts in and around a pool so they share the same electrical potential, preventing current from passing through a swimmer. It is a life safety requirement under National Electrical Code Article 680 as adopted locally, and it is inspected.

Where should the pool equipment go?
Somewhere with service access, sensible plumbing runs, and consideration for noise, both for you and your neighbors. It is far easier to place well during design than to relocate afterward.

Can I take pictures of the plumbing before it is covered?
You should. Photograph the steel and plumbing from several angles before gunite. It is the only permanent record of what is inside your pool, and it costs nothing.