Big Rectangle Pools: Why the Metric 12×24 Might Be Your Smart Alternative

Search for “big rectangle pool” and you’ll find a lot of Pinterest boards and very few straight answers about what it actually costs, how long it takes to install, or what your options are beyond pouring concrete.

Here’s the practical guide. If you want a straightforward rectangular pool between 12’x24′ and 16’x32′ — no vanishing edges, no free-form curves, just a proper pool for swimming laps, entertaining, and cooling off in July — you have more options than you think.

The rectangle pool sizes people actually buy

The Metric Series by Radiant Pools, which we’re an authorized Idaho dealer for, offers five standard Metric Rectangle sizes:

• 8′ × 12′ — plunge / cold-plunge use, tight yards. ~3,000 gal, 2–3 people.
• 12′ × 16′ — compact yards, first-time pool owners. ~6,500 gal, 3–5 people.
• 12′ × 24′ — small family with light lap swimming. ~13,500 gal, 4–6 people.
• 16′ × 28′ — the most-quoted rectangle in Idaho. ~21,000 gal, 6–8 people.
• 16′ × 32′ — serious lap swimming + entertaining. ~24,000 gal, 8–10 people.

The 16’x28′ is the “just right” for most Boise, Meridian, and Nampa lots — big enough for real swimming and entertaining, small enough to fit standard 1/4 to 1/3 acre backyards.

Two ways to build it

Once you’ve picked the size, you have two real construction paths. Both give you the same water shape. The differences are cost, install time, and long-term maintenance.

Option 1: Gunite (traditional in-ground concrete)

• National cost for a 14×28 in 2026: $65,000 – $150,000 all-in
• Install time: 5–8 months (permitting through first swim)
• Refinishing: every 10–15 years at $6,000 – $15,000
• Shape flexibility: infinite — but if you’re building a rectangle you’re paying for flexibility you’re not using

Option 2: Modular Metric panel-built

• National cost for a 14×28 equivalent in 2026: $30,000 – $70,000 all-in
• Install time: 3–5 weeks total
• Liner replacement: every 15–25 years at $4,500 – $8,500
• Shape flexibility: five standard rectangle sizes from 8×12 through 16×32

On identical 14×28-equivalent quotes, our customers save $35,000–$80,000 by going Metric — money that often gets redirected to nicer decking, a bigger heater, a saltwater system, or an attached hot tub.

Why modular got good enough to compete

Ten years ago, “modular pool” meant a step-in kit that lasted 5–8 years. That’s not what’s happening now.

The Metric system we install uses 2-inch insulated aluminum wall panels with a closed-cell EPS foam core — technology originally developed for the NASA Space Program and refined by Radiant Pools (originally Trojan Pools) for over 60 years. The structural warranty is non-prorated and fully transferable for the lifetime of the pool.

The rectangle-specific advantage

Here’s the thing nobody says out loud: if you’re building a rectangle, gunite’s biggest selling point — custom shape — doesn’t apply to you. You’re paying premium price for a feature you’re not using.

That’s why the modular-vs-gunite math flips so hard for rectangular pools specifically. Free-form curves and vanishing edges? Get gunite. Rectangle? You should at least look at Metric before signing.

What a 16×28 Metric install looks like

• Week 1: Site survey, final design, permits pulled
• Week 2: Excavation, gravel base, footings
• Week 3: Panel assembly, plumbing, equipment pad
• Week 4: Liner install, water fill, chemical startup
• Week 5: Decking, fencing final, first swim

Frequently asked questions

What sizes of big rectangle pool does Metric offer?

Five Metric Rectangle sizes: 8’×12′, 12’×16′, 12’×24′, 16’×28′, and 16’×32′. If you need bigger, we can quote a Metric Grecian (up to 17’×41′) or a Metric Freeform (up to 20’×33′).

Can I get a big rectangle pool in a 12×24 lot?

Yes — 12×24 IS the rectangle for a tight lot. If you have 18’x30′ of backyard with 3′ clearance on each side, you can install a 12×24 Metric Rectangle with equipment pad and basic decking.

How deep can a Metric rectangle pool go?

Standard Metric configurations go from 3’6″ shallow to 6′ deep. Deeper diving-well configurations are gunite-only territory.

Do modular pools crack like gunite?

Gunite pools develop hairline cracks and require resurfacing every 10–15 years. Metric pools don’t crack because there’s no rigid shell to crack; the aluminum panels flex micro-fractions and the liner is replaced every 15–25 years. Different failure mode, similar total cost of ownership.

Will the HOA / county approve it?

Idaho counties treat a permanent Metric pool as an in-ground pool for permitting purposes as long as it’s properly excavated and set. We pull permits on every install. 95%+ of Idaho HOAs approve Metric the same as gunite.

The next step

If a 12×24, 16×28, or 16×32 rectangle is what you’re picturing, we can quote both options side by side. No pressure to pick Metric. Sometimes gunite is still the right answer. But we won’t sell you a $130K pool if a $58K Metric gets you the same swim experience.

Start with a free backyard assessment or visit our Meridian showroom to see a working Metric pool in person.

Full Metric modular pool specs, sizes, and pricing are on our product page.