Hardscape Materials Guide: Patios, Paths and Walls
Compare patio and path materials, from concrete and pavers to flagstone, gravel, DG and decking, with typical base depths, drainage slope and wall limits.
· 7 min read · OpenLandscape3D editorial
Hardscape is the built framework of a landscape: patios, paths, steps, decks, edging and walls. It is usually the most expensive and longest-lasting part of a project, and the hardest to change later. The visible surface gets most of the attention. Most failures, though, such as heaving, settling, puddling and cracking, come from what is underneath: the base, the drainage and the edges.
This hardscape materials guide compares common surfaces, explains typical base preparation and slope, and covers the climate factors and wall limits that should shape your choices. Base depths below are typical ranges for residential work. Always follow the manufacturer's installation instructions and your local building code, which take precedence.
Compare surface materials
| Material | Character | Strengths | Watch-outs | Relative cost |
|---|---|---|---|---|
| Gravel | Loose, informal | Permeable, quick to install, easy to change | Migrates without edging; hard for wheels, chairs and snow shovels | Lowest |
| Decomposed granite (DG) | Fine, compacted, natural | Permeable (unstabilized), natural look in dry climates | Tracks indoors; erodes on slopes; stabilized forms drain less | Low |
| Poured concrete | Smooth or textured slab | Durable, versatile, smooth for wheels | Cracks if base or joints are poor; deicing salts can damage the surface | Moderate |
| Concrete pavers | Modular units on sand | Repairable unit by unit; many styles | Needs a good base and edge restraint; joints need maintaining | Moderate to high |
| Permeable pavers | Pavers with open joints over an open-graded base | Infiltrates rainfall; can reduce runoff | Deeper, specialized base; joints need periodic cleaning | High |
| Natural stone (flagstone) | Irregular or cut stone | Natural, durable, distinctive | Uneven surface if dry-laid; varies in hardness and porosity | High |
| Wood decking | Framed structure | Works on slopes and over uneven ground | Ongoing maintenance; rot and insects where detailing is poor | Moderate to high |
| Composite decking | Framed structure with manufactured boards | Low surface maintenance | Can get hot in sun; framing still needs care | High |
Relative costs vary a lot by region, site access, design complexity and the specific product. Treat this as a rough ranking only and get local quotes.
Base preparation
Why the base matters
The base carries the load, spreads it into the subgrade, and lets water drain away. Most residential surfaces sit on compacted crushed aggregate (often called road base, crusher run or a local equivalent) over undisturbed or properly compacted subgrade. Topsoil and organic material should be removed first, because they compress and decay.
Typical base depths
| Surface | Typical base (compacted) | Notes |
|---|---|---|
| Gravel path | 5–10 cm (2–4 in) aggregate, plus 5–8 cm (2–3 in) surface gravel | Fabric between subgrade and base is common |
| Decomposed granite path | 5–10 cm (2–4 in) base, plus 5–8 cm (2–3 in) DG | Compact DG in thin lifts; stabilized DG per supplier |
| Paver patio or walkway | About 10–15 cm (4–6 in) base, plus about 25 mm (1 in) bedding sand | Deeper on clay, poorly drained or freeze-prone sites |
| Paver driveway | About 20–30 cm (8–12 in) or more base | Vehicle loads; follow manufacturer and local guidance |
| Permeable pavers | Often 15–30 cm (6–12 in) or more of open-graded stone | Depth depends on storage, soils and traffic; follow manufacturer design |
| Concrete patio slab | Often 10 cm (4 in) slab over 10 cm (4 in) compacted base | Reinforcement and control joints per local practice |
| Flagstone | Dry-laid on compacted base and sand or screenings, or mortared on a concrete slab | Mortared flagstone needs a sound slab beneath |
Compact the base in layers (lifts), usually no more than about 5–10 cm (2–4 in) at a time, with a plate compactor. One thick, loosely compacted layer settles unevenly.
Decks are different. They sit on posts and footings rather than a base. Footing depth, size and spacing, ledger attachment, railing heights and lumber ratings are governed by local building codes. In cold climates, footings must typically extend below the local frost depth.
Slope for drainage
Every solid surface should shed water away from buildings. A common target is a 1–2% slope, about 3–6 mm per 30 cm (1/8–1/4 in per foot), falling away from the house.
- A 4 m (13 ft) deep patio at 1.5% falls about 6 cm (2.4 in) from the house edge to the outer edge.
- Steeper than about 2% starts to feel noticeable underfoot and makes furniture rock.
- Too flat leaves puddles, which freeze in cold climates and grow algae in humid ones.
Build the slope into the subgrade and base, not just the bedding sand. Direct water to a lawn, bed, rain garden or drain, not to a neighbour's lot or a basement window well. Where the yard slopes toward the house, deal with grading and drainage before building hardscape.
Edging and edge restraint
Edges keep materials in place and define the design.
- Pavers need edge restraint, such as plastic or aluminium paver edging spiked into the base, a concrete haunch, or a soldier course set in concrete. Without it, pavers creep outward and joints open.
- Gravel and DG need a firm edge, such as steel, aluminium, stone or a concrete curb, to stop material migrating into lawn and beds.
- Steel edging gives a clean, thin line between beds and lawn or paths. Choose a thickness suited to your soils and frost conditions.
- Mow strips of brick or concrete at lawn edges make mowing easier.
Climate factors
Freeze-thaw
In cold regions, water in the base and the material itself expands as it freezes:
- A well-drained, adequately deep base is the main defence against frost heave.
- Choose pavers and stone rated for freeze-thaw exposure. Some soft or porous stones spall.
- Deicing salts can damage concrete, especially new concrete in its first winter, and harm adjacent plants. Use sand for traction where practical, and check product guidance before using salt.
- Flexible systems such as pavers and dry-laid stone tolerate minor movement better than rigid slabs, and they are easier to repair.
Heat
In hot, sunny regions:
- Dark pavers, stone and composite boards can get uncomfortably hot underfoot. Lighter colours stay cooler but can cause glare.
- Large expanses of paving and gravel near walls add reflected heat to the house.
- Shade from trees, pergolas and shade structures does more for comfort than material choice alone.
Retaining walls
Retaining walls hold back soil where grade changes. The forces involved grow quickly with height.
- Short garden walls (often under about 0.6–0.9 m, or 2–3 ft) built from segmental concrete block or dry-stacked stone are common DIY projects when built on a compacted base with drainage.
- Taller walls, often those over about 1.2 m (4 ft) measured from the bottom of the footing, commonly require a building permit and an engineered design. That limit can be lower where a wall supports a slope, driveway, building or other load (a surcharge). Requirements vary by jurisdiction, so check your local code before you design.
- Drainage is essential. Most walls need free-draining gravel behind them and often a perforated drain pipe at the base to relieve water pressure. Many wall failures start with trapped water.
- Segmental block walls above modest heights typically use geogrid reinforcement layered into the backfill, per manufacturer specification.
- Terracing with two shorter walls set well apart can avoid a single tall wall. Spacing must be enough that the upper wall doesn't load the lower one, so get guidance where heights are significant.
Before digging footings or trenches, contact 811 to have utility lines marked.
Choosing materials
A practical sequence:
- Use and traffic: dining, wheelchairs and strollers, vehicles, or occasional foot traffic.
- Climate: freeze-thaw and deicing, heat, or heavy rain.
- Drainage: is permeability needed or required locally?
- Style: match the house and the regional character.
- Maintenance: sealing, joint sand, weeding, raking or staining.
- Budget and access: can materials and equipment reach the site?
Our backyard landscape planning guide covers how hardscape fits into the overall layout.
How OpenLandscape3D helps
The hardscape tools let you draw patios, paths, decks, driveways, gravel and mulch areas, and add fences, stone or block retaining walls, edging and gates. You can set spot elevations to record grade changes (terrain), though cut-and-fill and slope calculations are not yet available. The OL-ONHARD check flags plants placed on hard surfaces. The materials estimate gives planning price ranges, not quotes, and it does not replace a contractor's takeoff or an engineer's design.
Frequently asked questions
Which is better, pavers or poured concrete?
Neither is better in every case. Poured concrete gives a smooth, continuous surface and is often less expensive. Pavers can be lifted and relaid to fix settling or reach utilities, and they hide minor movement better. Base preparation matters more than material for both.
How deep should a paver base be?
For pedestrian patios and walkways, typical guidance is about 10–15 cm (4–6 in) of compacted aggregate plus about 25 mm (1 in) of bedding sand. Use more on clay, poorly drained or freeze-prone sites, and much more for driveways. Follow the paver manufacturer's guidance.
Do I need a permit for a patio or retaining wall?
Many ground-level patios don't need a permit, but rules vary. Retaining walls taller than about 1.2 m (4 ft), or walls that support loads, commonly do. Decks frequently require permits. Check with your local building department.
Is decomposed granite good for patios?
It works well in dry climates for informal, lightly used patios and paths. It can track indoors, soften when wet and erode on slopes. Stabilized DG is firmer but less permeable. Use firm edging and a compacted base.