DIY Retaining Wall for Above Ground Pool: Step-by-Step Guide: 1 Minute to Understand How to Build a Safe, Attractive Wall

I’ve built and overseen dozens of small retaining walls around above-ground pools, and the most successful ones always start with disciplined planning, reliable drainage, and a clean, ergonomic workflow. Pools impose continuous lateral pressure on soil and structures nearby; the wall isn’t holding the pool, it’s holding back the earth that surrounds your pool apron. Done right, you reduce erosion, prevent frost heave damage, and keep your deck and equipment stable.

Two data points guide my approach. First, noise and vibration travel easily through hollow grounds and decks; Steelcase notes that unwanted noise impairs task performance and perceived comfort by up to 36%, which matters when a pump sits close to a hardscape (steelcase.com/research). A compacted base and dampened wall core can reduce resonance around mechanicals. Second, moisture control directly affects occupant health and material longevity; WELL v2 emphasizes site drainage and moisture management as prerequisites for healthier environments (v2.wellcertified.com). Those principles translate to a pool yard: get water away from the wall and you’ll extend its life—and keep the pool surround safer underfoot.

Assess Site Conditions and Code

Walk the perimeter after a rain to map how water moves. Mark the pool’s high side (upslope) and low side (downslope). Note utilities, property lines, and setbacks. Many jurisdictions limit DIY retaining walls to about 3–4 ft (0.9–1.2 m) without engineering. If your grade requires more than that, plan for terracing or hire a structural engineer. Measure the vertical cut you need to level the pool area and add 6–12 in (150–300 mm) for freeboard and drainage behind the wall.

Choose the Right Wall Type

For most above-ground pool settings, I prefer dry-stacked concrete segmental retaining wall (SRW) blocks with interlocking lips or pins. They’re modular, forgiving for DIY, and allow controlled movement. Timber can work but requires careful waterproofing and is less durable near irrigation or chlorinated splash. Poured concrete is strong but less forgiving and needs formwork, reinforcement, and drainage details to avoid cracking. Match the wall’s curve to your pool’s geometry; gentle arcs distribute soil pressure more efficiently than sharp angles.

Plan the Layout and Set the Line

Snap a string line to define the face of the wall. For curves, use a garden hose or flexible PVC as a guide, then transfer to marking paint. Keep generous clearances from the pool wall to protect the liner and allow service access for pumps, hoses, and winter covers—typically 24–36 in (600–900 mm) around the perimeter. If you’re testing different footprints, a quick interior layout planner helps visualize deck edges, equipment pads, and pathways relative to the wall. Try a room layout tool to simulate spacing before you dig: room layout tool.

Materials and Tools

- SRW blocks rated for retaining use (check manufacturer’s spec for maximum gravity wall height)

- Crushed stone base (3/4 in, angular), and clean drainage gravel (#57)

- Landscape fabric (non-woven) for soil separation

- Perforated drain pipe (4 in) with sock

- Block adhesive (for cap course)

- Plate compactor, hand tamper, shovel, pick

- Level, string line, stakes, mallet

- Diamond blade for block cuts, safety gear

Excavation and Base Preparation

Cut back into the slope to create a trench for the wall footing. Typical trench: wall block depth + 6 in (150 mm) front and back, and 8–12 in (200–300 mm) deep. The first course sits partially buried—usually 10% of wall height, at least half a block—so plan depth accordingly. Lay 4–6 in (100–150 mm) of compacted crushed stone in lifts of 2 in (50 mm). Compact to refusal with a plate compactor. A level, dense base prevents differential settlement and reduces low-frequency vibration near pump pads.

Set the First Course

Everything depends on this course. Establish your highest point and set the first block flush to the string line and dead level front-to-back and side-to-side. Step down along slopes in full block increments to maintain level. Remove any rocking by screeding the base stone and tapping with a mallet. Maintain consistent batter (wall lean) as specified by the block system—typically 4–8 degrees.

Drainage Behind the Wall

Place landscape fabric against the excavated soil. Lay the perforated drain pipe at the base, daylighting to a swale or lower grade away from the pool. Backfill directly behind blocks with 12–16 in (300–400 mm) of clean gravel up as you go, compacting every 6–8 in (150–200 mm). Keep native soil separated from the gravel with fabric to prevent fines from clogging. Proper drainage minimizes hydrostatic pressure and frost heave—two common causes of wall failure.

Stacking Subsequent Courses

Brush each course clean of chips. Stagger vertical joints at least half a block. Engage lips or pins per manufacturer instructions and check batter regularly. For curves, split blocks as needed to maintain the arc—avoid forced tight joints which telegraph as cracks later. Stop periodically, stand back, and sight the wall for consistent rhythm and shadow lines under natural light.

Backfill and Compaction Strategy

As the wall rises, continue placing gravel directly behind it and compact in lifts. Beyond the gravel zone, place native soil or a well-graded fill compacted to firm support (hand tamper near the wall, plate compactor further back). Pitch the finished grade 2–3% away from the pool and wall so stormwater sheds quickly. If you plan a deck, reserve a stable sub-base now to simplify later framing or paver installation.

Capping, Edging, and Safety Clearances

Glue cap units after the wall has settled a day and the surface is dry. On pool sides with foot traffic, select caps with a rounded arris to reduce trip impacts. Maintain non-slip textures near wet areas. Keep a clear 18–24 in (450–600 mm) buffer from caps to the pool wall for safe circulation and emergency egress. Verify that skimmer, return lines, and pump access aren’t obstructed by the wall or backfill.

Integrating Ergonomics, Color, and Acoustics

- Ergonomics: Keep equipment pads at a comfortable service height (24–30 in above grade if elevated) and allow a 36 in maintenance aisle.

- Color psychology: Neutral, cool grays around water read calmer and larger; a desaturated stone with a slightly warmer cap balances the blue of the pool without glare.

- Acoustic comfort: If pump noise reflects off the wall, line a small section behind equipment with a mineral-fiber panel concealed in a cedar screen; the mass plus absorption cuts hum without creating a safety hazard.

Moisture, Frost, and Regional Adjustments

In freeze-thaw climates, deepen the base to sit below local frost depth where feasible or increase the gravel envelope and drainage performance. In high-rainfall regions, upgrade pipe diameter and add cleanouts at turns. On sandy coastal soils, consider geogrid reinforcement per the block system’s tables when wall heights approach limits or when surcharges (decks, sheds) sit near the crest.

Common Mistakes I Avoid

- Skipping a drain pipe or using pea gravel that clogs

- Setting caps before the wall has settled and dried

- Building too close to the pool, restricting cover installation

- Overcompacting right against the wall, which can push the face out

- Forgetting a continuous fabric separation between soil and gravel

Maintenance and Seasonal Checks

Each spring, walk the wall line. Look for bulges, open joints, or standing water at weep points. Clear leaf litter from outlets. After heavy storms, confirm that the daylighted pipe flows. If a block chips, replace the unit—dry-stack systems make repairs straightforward.

Estimated Timeline and Effort

For a 30–40 ft curved wall at 24–30 in high, a two-person team typically spends one weekend on excavation and base, one day on stacking and backfill, and a half day on caps and cleanup. Rent the plate compactor; it’s the best money you’ll spend on durability.

FAQ

How close can a retaining wall be to an above-ground pool?

I leave 24–36 in of clearance for circulation, liner care, and service access. Local code or pool manufacturer guidance may require more near skimmers and returns.

Do I need geogrid for a 2–3 ft wall?

Often no for a true gravity SRW, but it depends on soil, slope, and surcharge. Check your block manufacturer’s charts. Add geogrid if you’re near the height limit or supporting a deck.

What base material is best under the wall?

Angular crushed stone (3/4 in) compacted in thin lifts. Avoid sand-only bases; they shift under load and water.

How do I manage water behind the wall?

Install a perforated drain at the heel of the first course, wrap in fabric, daylight to grade, and use clean gravel backfill with a fabric separator. This aligns with moisture management emphasized in WELL v2 for healthy, durable environments.

Can I use timber for a pool-side retaining wall?

Yes with proper waterproofing, deadmen, and drainage, but lifespan is shorter in wet, chlorinated environments. Concrete SRWs offer longer service with easier repairs.

Will the wall reduce pump noise?

A dense, well-compacted base and gravel core reduce resonance. Adding a small absorptive screen near equipment helps; Steelcase research links reduced noise to better comfort and performance, so it’s worth the effort (steelcase.com/research).

How do I prevent frost heave from pushing the wall?

Use a deep, well-drained gravel base, keep water moving with a reliable outlet, and separate fines with fabric. In colder zones, lower the base and improve drainage capacity.

What finish cap is safest near wet feet?

Choose textured caps with eased edges and a matte finish to cut glare and improve traction. Avoid highly polished or dark caps that overheat in sun.

Should the wall be perfectly straight or curved?

Curves distribute pressure more smoothly and blend better with round pools. If you go straight, break long runs with gentle returns for visual rhythm.

Can I place a deck right behind the wall?

You can, but confirm surcharge limits and consider geogrid or a footing independent of the wall. Keep deck posts set back from the gravel zone to avoid undermining.

How high can I build without a permit?

Varies by jurisdiction; many cap unengineered walls at 3–4 ft. Always verify with your local building department before starting.

What’s the fastest way to visualize the layout?

Mock curves with a hose, then refine digitally with an interior layout planner to check clearances around equipment and pathways. A quick pass with a layout simulation tool prevents costly miscuts.