Can I Use Leftover Roof Tiles as a Decorative Driveway Edging?

Repurposing leftover roof tiles as driveway edging is a creative idea that many Kiwi homeowners have tried — and it can look great when done right. The short answer is yes, it's generally possible, but the outcome depends heavily on the type of tiles you have, how you install them, and the conditions in your specific part of New Zealand.

What Types of Roof Tiles Work Best?

Not all roof tiles are equally suited to ground-level edging duty. Here's a quick breakdown:

Concrete roof tiles are the most practical choice. They're heavy enough to stay in place, resist moisture, and are widely used in NZ homes. Terracotta tiles look beautiful but can be brittle — if you're in a frost-prone area like Central Otago or the Central Plateau, repeated freeze-thaw cycles may cause them to crack over time.

Key Considerations Before You Start

Condition of the Tiles

Inspect every tile carefully before repurposing it. Look for:

• Hairline cracks that will worsen once the tile is set in the ground
• Moss, lichen, or algae — clean these off thoroughly before installation
• Old mortar residue — chip this away for a cleaner finish

Discard any tiles that are cracked through or structurally compromised. Ground-level use exposes tiles to moisture from below, which accelerates any existing damage.

Drainage and the NZ Building Code

Driveway edging affects how water drains away from your property. Under NZ Building Code clause E1 (Surface Water), surface water must be managed so it doesn't cause damage to your property or neighbouring properties. Poorly placed edging that traps water against a foundation or directs runoff onto a neighbour's land could create real problems. Keep edging at least 150 mm away from any building foundation, and ensure your driveway still drains freely toward the road or a suitable outlet.

For most decorative edging projects, a building consent is not required under Schedule 1 of the Building Act — but always confirm this with your local council before starting, as rules can vary.

Ground Preparation

Good preparation is the difference between edging that lasts years and edging that tips over after the first winter. Follow these steps:

1. Mark your edging line with string or a garden hose to get a smooth, consistent curve or straight run.
2. Excavate a trench approximately 100–150 mm deep and slightly wider than your tile thickness.
3. Compact the base — a layer of compacted AP20 (all-passing 20 mm) aggregate or crusher dust gives a stable, free-draining bed.
4. Set tiles in mortar or dry-pack — a stiff mortar mix (roughly 4:1 sand to cement) or a proprietary bedding mortar works well. Sika and Ardex both offer suitable bedding and jointing products available through NZ trade suppliers.
5. Backfill and compact soil on the garden side once the mortar has cured (allow at least 24–48 hours).

Orientation Options

Roof tiles used as edging are typically set:

• Vertically on edge — gives a taller, more formal border (best for flat or low-profile tiles)
• At an angle (sawtooth style) — a classic cottage-garden look, with tiles set at roughly 45 degrees
• Flat and overlapping — mimics a low retaining edge; works well with larger concrete tiles

The sawtooth style is popular in NZ gardens and makes good use of the natural profile of a curved roof tile.

Safety Considerations

• Broken tile edges are extremely sharp — always wear heavy-duty gloves and safety glasses when cutting or handling tiles.
• If you need to cut tiles to fit, use an angle grinder with a diamond blade or a tile saw. Wear a P2 dust mask, as tile dust (especially from older tiles) can be harmful. Check WorkSafe NZ guidance on working safely with silica-containing materials.
• Older tiles (pre-1990s) may contain asbestos-containing materials, particularly in the coating or underlays. If you're unsure of the age or origin of your tiles, have them tested before cutting or disturbing them. Do not cut or grind any material you suspect may contain asbestos.

Finishing and Maintenance

Once installed, concrete or terracotta edging benefits from a penetrating sealer to reduce moisture absorption and moss growth. Resene and Dulux both stock masonry sealers suitable for exterior use. Reapply every few years, or as the manufacturer recommends.

Check your edging each spring for any tiles that have shifted, heaved, or cracked over winter, and re-bed or replace as needed.

When to Call a Professional

For simple decorative edging on a flat residential driveway, this is a manageable DIY project for a competent homeowner. However, consider calling a qualified driveway layer or landscaper if:

• Your driveway has a significant slope and drainage is complex
• You're edging a long run (20 m+) and want a professional finish
• The ground is unstable, clay-heavy, or prone to subsidence
• You need to integrate edging with existing concrete kerbing or channel drains

A skilled tradesperson will also be able to advise on whether your chosen tiles are genuinely fit for purpose. You can find experienced local driveway layers and landscapers on tradedirectory.co.nz.

Sources & Further Reading

• MBIE Building Performance – Building Code clause E1 Surface Water
• WorkSafe NZ – Working safely with hazardous substances and dust
• BRANZ – Guidance on NZ construction and materials
• Sika NZ – Bedding and jointing products
• Resene – Exterior masonry sealers
• Ardex NZ – Tile and stone installation products