Residential Pool/Spa Contractor/Trade Knowledge

Structure & Shell

20% of this exam

How a concrete pool gets built and why it stays in the ground: excavation and soil support, steel and shotcrete/gunite shells, finishes and coping, and the forces — settlement and groundwater — that crack or float pools when the details are skipped. Questions test the construction sequence and the reason behind each detail.

Core concepts

The sequence is the story

Excavate to grade from a benchmark elevation → set plumbing rough-in and tie the steel grid → shoot the shell (gunite = dry mix with water added at the nozzle; wet-mix shotcrete arrives mixed) → tile and coping → deck → plaster last, then fill. Questions love to ask what comes before what.

The shell is only as good as the soil

Overdig cannot be fixed by pushing loose soil back — uncompacted fill settles and leaves the shell unsupported. Correct it with compacted fill, lean concrete, or a thickened section. On wet sites, dewater with sump or well points so steel and concrete go in dry.

Water pushes both ways

A full pool pushes out; a high water table pushes up. A hydrostatic relief valve in the main drain sump lets groundwater into an empty shell so the pool doesn't float. Never drain a pool in wet ground without thinking about uplift.

Joints and cracks have meanings

An expansion joint isolates deck movement from the beam and coping. A water stop embedded across a cold joint blocks seepage where two placements meet. Structural cracks go through the shell (settlement, soil movement) and can leak; check cracks (crazing) are shallow plaster shrinkage and cosmetic.

Key facts to know cold

Gunite vs wet-mix shotcreteGunite: dry mix in the hose, water at the nozzle; wet-mix: fully mixed before pumping

Steel placementTied as a grid after excavation/plumbing, before the shell is shot

Hydrostatic relief valveIn the main drain sump; admits groundwater to keep an empty shell from floating

OverdigFill with compacted material or lean concrete — never loose soil

Waterline tileCleanable glazed band where oils and scale collect; plaster would stain and etch

Coping typesCantilevered = deck poured over the beam edge; precast = separate units set in mortar

Where it lives in your books

The real exam is open book. Knowing which book — and which tab — answers this domain is worth as much as memorizing it.

manual

Pool References

Safety and barrier questions are code lookups; hydraulics questions are formulas. Keep the formula sheet (turnover, volume, TDH) tabbed in the handbook and the barrier rules tabbed in the code.

9 recommended tabs

code

Florida Building Code

Code questions give themselves away with words like 'minimum', 'required', or 'permitted'. Go to the code — never answer a code question from memory when the book is on the desk.

9 recommended tabs

Lookup strategy

· Shell, deck, and elevation requirements are code lookups in the FBC pool provisions; construction-method questions (gunite, water stops, dewatering) come from the handbook side.
· If a question describes a crack or failure, ask what moved: soil under the shell = structural, plaster shrinkage = cosmetic crazing.
· Shotcrete placement questions (wet vs dry mix, rebound, curing) answer from the ACI Guide to Shotcrete; rebar support and clearance from Placing Reinforcing Bars — both are on the approved list.

Reading isn't learning — retrieval is.

32 questions in this domain, each with an explanation and source.