# Lagoon pool with a cabana near the beach in Kailua

A freeform with a rock waterfall and a thatch-roofed cabana, a short walk from the sand. Drawn for a Hawaiian plantation-style beach house with a green metal roof, white lap siding and a wraparound lanai, with a sandy yard with coconut palms, plumeria, hibiscus, ti plants and the Koʻolau mountains behind.

A design idea for Kailua, HI. Hawaii, coastal, Coastal. Updated 2026-10-06.

## The numbers

- Size: 30 × 15 ft (3.5 to 5.5 ft deep)
- Water surface: 360 sq ft
- Water: about 9,000 gal
- Coping: 73 linear ft
- Deck: 1,330 sq ft

## The design, spelled out

The floor is 3.5 ft deep at the steps and stays level for about 8 ft, slopes over about 10 ft, then runs level at 5.5 ft for the last 11 ft. A sun shelf sits at the other end.

### Shape: Freeform

A pool with natural, flowing curves. Curves relax a yard and work with planting, a rock feature or a tub, at the cost of a more complicated cover.

### Size: 30 × 15 ft

A pool about 15 ft wide and 30 ft long. A common family size with room for play and a short swim. That is about 360 sq ft of water and about 9,000 gallons.

### Steps: Curved steps

Curved, wedding-cake steps. A formal, graceful way into a Roman or larger pool. The steps lead into water 3.5 ft deep.

### Sun shelf: With loungers

A sun shelf sized for chairs in the water. Lets you sit in the cool water in the sun with a drink, which is why it works well in a hot climate.

### Pool finish: Pebble

An exposed pebble aggregate finish, in the Pebble Tec style. Durable and textured, which hides small marks, but rougher on bare feet.

### Finish color: Tan finish, sandy turquoise water

A tan interior. Gives a green-blue lagoon look.

### Waterline tile: Sea glass

Sea-green glass mosaic at the waterline. A soft, coastal line that warms the water. It runs about 73 linear ft around this pool.

### Coping: Flagstone

Natural flagstone with irregular edges. Gives a natural, informal look that blends with planting and rock. It runs about 73 linear ft around this pool.

### Deck: Light concrete

Light, textured concrete finished to stay cool. A practical choice where the summer sun is strong and kids run barefoot. The deck is about 1,330 sq ft here.

### Planting: Tropical

Palms, bird of paradise and big-leaf plants. Creates a resort feel and screens the neighbors in a warm, humid climate.

### Water features: Rock waterfall

Rock waterfall: A natural rock waterfall. Gives a lagoon look and a strong sound, and uses more space than a wall feature.

### Add to the yard: Cabana

Cabana: A small, open-sided cabana beside the pool. A shady place to change, nap or stash towels. It needs a footing and often a permit.

### Furniture: Loungers, Umbrella

Loungers: A pair of chaise loungers. The first thing people want on a pool deck. Umbrella: A market umbrella. Cheap shade that you can move with the sun.

### Light: Golden hour

Shown in golden-hour light. Low sun is when the finish, the tile and the planting look their best.

## Why it suits this house

The yard: a sandy yard with coconut palms, plumeria, hibiscus, ti plants and the Koʻolau mountains behind. A coastal pool deals with wind, salt and a view, so materials and shelter shape the design. Wind chills the water and carries salt. A low wall, a glass fence and tough fittings let the pool take in the view without punishment from the weather.

The house is a Hawaiian plantation-style beach house with a green metal roof, white lap siding and a wraparound lanai. A coastal house wants light colors, natural wood and a view that stays open. A clean rectangle, a glass fence, pale coping and a wood-look deck keep the yard bright and let the ocean air and light do the work.

## Will it fit your yard?

Plan on a clear area of about 48 by 33 ft for the pool, 4 ft of deck around the water and 5 ft to the fence line. The deck as drawn here is about 50 by 35 ft.

## Hawaii: what the climate asks of this pool

A Hawaii pool is open year round, so salt air, rain and trade winds matter more than a winter plan.

- Salt air and humidity are hard on metal, light fittings and some stone. Ask for marine rated parts.
- Heavy rain comes in bursts. Deck drainage and where the overflow goes need a plan.
- Trade winds cool the deck and blow debris into the water, so skimmer placement and planting choices count.
- Island logistics can add time to materials and equipment. Ask for lead times before you settle on a finish.

## Quick answers

**How much water does this pool hold?** About 9,000 gallons. It is 30 by 15 ft with about 360 sq ft of water, 3.5 ft deep at the steps and 5.5 ft at the deep end. The gallons come from adding up the depth over the real floor, steps and shelf included.

**How big a yard does it need?** Plan on a clear area of about 48 by 33 ft for the pool, 4 ft of deck around the water and 5 ft to the fence line. The deck as drawn here is about 50 by 35 ft.

**What does this design cost?** A planning range for HI is $50,000 to $145,000 all in: the pool, deck, coping, fence and features listed on this page. Permits and engineering are not in it. It is a range built from published prices, not a quote, and real jobs usually land inside it rather than on its edges.

**How long does it take to build?** Plan on about 3 to 6 months from a signed contract to the first swim. Permits take from a few days to several months, depending on the town, before work starts.

## Why it works here

Coconut palms, plumeria and sand call for a relaxed freeform shape, so tan pebble with sea glass waterline tile and flagstone coping stays soft against the white siding. A rock waterfall, a sun shelf with loungers and a thatch-roofed cabana give the 30 x 15 pool places to sit.

What to watch: Near the beach, salt air and sun wear on metal fittings and furniture, and a pool with no fence leaves the water open. A thatch-roofed cabana also drops leaves and needs upkeep.

## What this will cost: a planning range

$50,000 to $145,000 for HI, a range from published prices and not a quote.

- The pool: $34,000 to $94,000. 359 sq ft of water at $90 to $250 a square foot (shell, excavation, plumbing, equipment, plaster). Steps and the sun shelf are part of the shell.
- Pebble interior: $4,000 to $4,000. 606 sq ft of shell at $6 a square foot above plaster. Pebble is $10 a square foot against $4 for plaster in both sources.
- Coping: $3,000 to $4,000. 73 linear ft at $40 to $55 a foot.
- Rock waterfall: $4,000 to $10,000. A medium rock waterfall. A grotto costs more.
- Cabana: $8,000 to $31,000. Priced at $150 to $600 a square foot for a custom pool house, over this cabana's footprint.

Sources: [US Bureau of Economic Analysis, Regional Price Parities by state](https://www.bea.gov/data/prices-inflation/regional-price-parities-state-and-metro-area); [HomeAdvisor, in-ground pool cost](https://www.homeadvisor.com/cost/swimming-pools-hot-tubs-and-saunas/inground-pool); [Fixr, gunite and concrete pool](https://www.fixr.com/costs/inground-gunite-concrete-swimming-pool); [Pool Research, plunge pool cost](https://poolresearch.com/plunge-pool-cost/); [ThePricer Media, pool resurfacing (quoting Angi, April 2026 data)](https://www.thepricer.org/how-much-does-pool-resurfacing-cost/); [Willsha Pools, pool finishes](https://willshapools.com/?p=5877); [Pool Research, pool coping cost](https://poolresearch.com/coping-cost/); [Simplified Pools, water features guide](https://simplifiedpools.com/blog/pool-water-features-fountains-guide/); [Block Renovation, building a pool house](https://www.blockrenovation.com/guides/building-a-pool-house-costs-design-tips)

## How long it takes

3 to 6 months from contract to first swim. Permits take from a few days to several months, depending on the town, before work starts.

- The yard additions are usually built after the pool is finished, so they add weeks that are not in this range.

## What it is made of

- Interior: Pebble, tan (about 610 sq ft of shell). Small stones set in cement. It is textured, hides wear and holds color well, and it is rougher on bare feet than the other finishes.
- Waterline tile: Sea glass (about 73 linear ft, 10 in. band). Sea-green glass adds color without matching the water, and it needs the same regular wipe as any glass tile.
- Coping: Flagstone (about 73 linear ft). Natural, irregular stone. It looks like it was always there and needs its joints watched for movement.
- Deck: Light concrete (about 1,330 sq ft). A light, textured concrete topping made to stay cooler underfoot. It wears over the years and can be recoated.
- Planting: Tropical. Palms, big leaves and lush planting. It needs water, wind and cold protection, and it drops leaves in the pool.
- Water feature: Rock waterfall. A natural stone waterfall. It needs space, a strong base and a pump sized for the flow, and it is the feature that most changes how the yard looks.
- Yard addition: Cabana. A small open-sided shelter beside the pool: shade, a changing spot and somewhere to keep towels.

## Keeping it up

- Pebble in this climate: Warm, humid weather feeds algae, and pebble's texture gives it something to hold on to, so brush it and keep the sanitizer steady.
- When it is resurfaced: Pebble is usually redone every 15 to 20 or more years, depending on the water and the builder (Shasta Pools, plaster versus pebble and Pebble Technology, support). On this pool that is about 610 sq ft of interior.
- Light concrete deck: A cool-deck topping wears with use. Wash it, patch chips early and plan to recoat it.
- Rock waterfall: A rock waterfall collects algae and leaves in the crevices. Plan on a spring clean and a check of the pump.
- Algae and storms: Warm, damp weather grows algae fast, so keep the sanitizer steady and circulation running. Secure loose furniture before a storm.
- Yearly running cost: Owners commonly budget $3,000 to $5,000 a year for chemicals, power, service and repairs (HomeAdvisor, in-ground pool cost, 2026).

## Questions to ask a builder

- Which fittings, fences and lights are marine rated, and how long do your materials take to arrive?
- Which fittings and equipment are rated for salt air this close to the sand, and where does the pump sit away from the cabana?
- How deep is the sun shelf, and can a chair sit on it without tipping?
- How much space does the rock waterfall take, and how is the rock secured and plumbed?
- Is the pebble finish rough on bare feet here, and how long does it last in my water?

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