How to lay a garden path with slabs starts with a compacted sub-base, a small fall for rain, and full mortar bedding so slabs don’t rock.
A slab path earns its keep fast: cleaner shoes, fewer detours, and a clear route to the shed. The part that decides how long it lasts sits out of sight. If the base is flat and firm, the top stays neat. If the base is soft or patchy, slabs tilt, joints crack, and puddles show up.
Below you’ll get a practical build to copy. It walks you through planning, levels, digging depth, sub-base compaction, full bedding, and tidy joints. You’ll finish with a path that feels steady underfoot and drains.
Plan The Route And Set A Sensible Width
Start with the route. Mark it with a hose or a line of sand, then walk it a few times. Check turns, door swings, and where a wheelbarrow needs room. Keep the path clear of low roof drips and downpipes if you can.
- Daily foot traffic: 600–800 mm works for one person.
- Wheelbarrow runs: 900 mm feels easier.
- Two people side by side: 1,100–1,200 mm feels relaxed.
Pick slab size with the route in mind. Large slabs lay quicker on straight runs. Smaller slabs follow curves with fewer awkward cuts. Textured finishes grip better in wet weather.
Build Specs At A Glance
| Build Element | Practical Target | Why It Matters |
|---|---|---|
| Finished height vs. lawn | 10–15 mm above grass | Keeps soil and clippings off the slabs |
| Dig depth (typical) | 150–200 mm below finish | Makes room for base, bedding, slab |
| Sub-base (walkway) | 75–100 mm compacted | Reduces settlement on most soils |
| Sub-base (wheelbarrow) | 100–150 mm compacted | Takes heavier point loads |
| Sub-base lift thickness | 50 mm per lift | Thin layers compact more evenly |
| Bedding mortar thickness | 30–50 mm | Gives adjustment room with strength |
| Fall for rain | 10–20 mm per metre | Moves water off the path |
| Joint width | 8–15 mm | Makes gaps consistent and fillable |
Tools And Materials To Gather
Having all you need on site keeps the work smooth. Hire a plate compactor if the path is longer than a few metres; it saves effort and gives a tighter base.
Tools
- Spade, shovel, rake, wheelbarrow
- Pegs, string line, tape measure
- Long straightedge and spirit level
- Rubber mallet
- Trowel and pointing tool
- Angle grinder with diamond blade (only if cutting)
Materials
- Paving slabs
- Type 1 MOT / road base / crushed stone
- Sharp sand and cement (or ready bedding mix)
- Jointing mortar or brush-in compound
- Edging units, if your design needs restraint
If you’ll cut concrete or stone, treat dust as a hazard. Read official guidance on respirable crystalline silica and use wet cutting or extraction with a fitted mask.
Set Levels With String Lines
Set the finished height first, then work down to your dig depth. Run string lines along each edge of the path. Keep them tight, measure width at several points, and adjust until both edges stay parallel.
Set a gentle fall right now. A drop of 10–20 mm per metre is enough for rain. Aim the fall away from buildings and out toward a lawn or border.
Excavate To The Right Depth
Remove turf and topsoil along the marked route. Keep the bottom reasonably flat and the sides tidy. Check depth often: slab thickness + 30–50 mm bedding + compacted sub-base. Add a little extra depth where ground feels soft.
Handle Soft Patches
If you find a spongy area, dig it out until you hit firm ground. Fill that pocket with compacted sub-base. This one fix can save you from a single slab that sinks months after you finish.
Lay And Compact The Sub-Base
Spread sub-base in 50 mm lifts. Rake a lift level, compact it, then repeat until you reach the planned height. A plate compactor gives the best result. On small paths, a hand tamper can work if you compact longer than you think you need.
Check level and fall as you build. If you spot a dip, top up and compact again. If you spot a hump, rake material away and compact. Don’t push on to mortar until the base feels firm under your boots.
Add Edge Restraint Where Needed
Open edges can drift over time. If your design has exposed sides, add edging now. Set kerbs or bricks on a thin concrete bed and back them with a concrete haunch on the outside. That restraint keeps the whole run straight.
How To Lay A Garden Path With Slabs Step By Step
Work in a steady rhythm: mix a small batch, bed one slab, check it, then move on. That pace keeps joints consistent and stops mortar going off in the barrow.
Mix Bedding Mortar
A common mix is 4 parts sharp sand to 1 part cement. Mix dry first, then add water a bit at a time until it holds shape when squeezed. It should feel damp and workable, not sloppy.
Wet cement can irritate skin. If you’re mixing by hand, follow HSE guidance on working with cement and wear gloves that keep slurry off your hands.
Bed Slabs Fully, Not On Dabs
Spread mortar slightly wider than the slab. Level it to 30–50 mm, then scratch shallow ridges with a trowel. Lower the slab onto the bed, wiggle it to seat it, then tap with a rubber mallet.
Check level across the slab and along the path. If it’s high, lift it and take a little mortar out. If it’s low, lift it and add more. Use spacers or thin timber offcuts to keep joint gaps even.
Keep Lines True
For straight runs, keep a string line along the slab edge as you work. Line the slab up to the string, then check the top with your straightedge. Small corrections made early stop big wobbles later.
Cut Slabs Cleanly
Mark cuts with a straightedge. Score the line on both faces, then finish the cut. Wetting the line reduces dust and helps the blade. On curves, spread cuts across several slabs so you avoid one skinny wedge near the edge.
Do A Dry Layout Before Mixing
Before you mix mortar, place a few slabs on the compacted base and check the spacing. Shuffle slabs so colours don’t clump, then mark cuts with chalk. This quick rehearsal shows where joints land at steps, gates, and corners, and it helps you avoid a skinny slice right at the start of the path. Lift the slabs back off in order so you can lay them again without guessing. If your slabs vary in thickness, group similar ones together so you don’t chase levels all day.
Joint The Slabs And Seal The Look
Let bedding firm up before jointing. You want slabs stable under light foot pressure before you start filling gaps.
Pick A Jointing Method
- Mortar pointing: Suits wider joints and stays tidy when packed well.
- Brush-in compound: Quick to apply; follow the maker’s joint width limits.
For mortar joints, mix a slightly wetter mortar than the bedding. Pack it into joints with a pointing tool, then strike it off to a neat finish. Keep mortar off slab faces. If you get smears, wipe them straight away with a damp sponge and clean water.
Troubleshooting After The Path Is Down
| What You Notice | Likely Cause | Fix That Works |
|---|---|---|
| A slab rocks when stepped on | Voids under the slab | Lift, re-bed on full mortar, re-check level |
| One area sinks after rain | Soft ground or thin sub-base | Lift that section, dig deeper, add compacted sub-base |
| Water sits in a shallow puddle | Low slab or weak fall | Lift and reset the low slab, restore the fall |
| Joints crack or crumble | Dry mix or early use | Rake out loose fill, repoint, keep joints lightly damp while curing |
| Weeds show up in joints | Gaps or blown-in seeds | Top up jointing and brush out seedlings early |
| Slabs drift sideways over months | No edge restraint | Add edging or a buried concrete haunch |
| White marks on slab faces | Salt bloom from cement | Let it weather, then brush dry; skip harsh acid cleaners |
Care That Keeps The Path Neat
Sweep leaves off before they break down into a slippery film. In shade, scrub with a stiff brush and water to slow algae. If you use a pressure washer, keep it moving and avoid blasting joint material out.
Check joints twice a year. If you see gaps, refill them before slabs start to move. Fixing joints early is quicker than lifting and re-bedding later.
Final Walk-Through Before You Call It Done
Run a straightedge across several slabs and feel for lips. A lip can trip toes and catch a wheel. Reset any slab that sits proud while the bedding still has some give.
Stand at each end and sight along the joints. If a line wanders, adjust the next slab or two rather than forcing one slab to take the whole correction. When the mortar sets, those small choices show up as clean, calm lines.
Once jointing has cured, rinse the path and sweep it clean. Then you’re done today. And next time someone asks how to lay a garden path with slabs, you’ll know it’s mostly about the base you can’t see.