How to Build a Paver Walkway on a Slope, Plus Paver Steps

You can build a paver walkway on a slope, and on a gentle grade it works well. The secret is not the pavers. It is a deep, compacted gravel base that follows the slope, a solid stop at the bottom so the pavers cannot creep downhill, and a plan for the water that will run down the walk every time it rains.

Once a slope gets steep, a sloped walk stops being safe in a Massachusetts winter. At that point the right answer is paver steps, or a mix of short sloped runs and steps with landings. This guide covers both, plus the related question of whether a patio can go on sloping ground.

It is written by Gerrior Masonry & Landscape Construction Corp., a family-owned masonry and hardscape company in Woburn, MA. We build walkways and steps across the area, and the advice below is what we look at on a sloped site before we quote one.

How steep is too steep for pavers on a slope?

Measure it first. Run a string from the top of the path to the bottom, level it with a line level, and measure the drop at the low end. Divide the drop by the length and you have the slope.

A useful reference is the federal accessibility standard. Under the 2010 ADA Standards for Accessible Design, a walking surface steeper than 1 in 20 is treated as a ramp, and a ramp may not be steeper than 1 in 12. A home walkway does not have to meet those rules, but they are a fair test of what people can walk comfortably. Past roughly the ramp limit, a paver walk becomes slippery when wet leaves, frost or packed snow sit on it, and that is when we recommend steps.

Why sloped paver walkways fail in New England

• Creep. Every footstep and every freeze-thaw cycle nudges the pavers a little downhill. Without a fixed restraint at the bottom, joints open at the top and pavers bunch at the bottom.
• Water in the base. Rain runs down the walk and into the joints. If it cannot escape sideways, it travels through the base, carries fines with it and leaves soft spots.
• Frost heave. A thin base on wet clay lets frost lift sections of the walk unevenly each winter.
• Joint sand washout. On a slope, sheeting water scours the joints. Our post on paver joint sand that keeps washing out covers that problem in detail.

How to install pavers on a slope, step by step

1. Mark the path and call Dig Safe. Massachusetts requires at least 72 hours notice to Dig Safe before you dig, not counting weekends and holidays, and you pre-mark the area first (Dig Safe homeowner guide). Call 811.
2. Dig to firm subgrade, following the slope. Strip all topsoil and roots. The excavation should run parallel to the finished surface, not in level steps. Do not "just dig down a couple of inches" on a steep grade; the base needs full depth everywhere.
3. Add the gravel base in thin lifts. Use 3/4-inch crushed gravel and compact it with a plate compactor in layers 2 to 3 inches thick. Unilock's installation guide calls for a 6 to 8 inch base under walkways and notes that clay soil needs deeper excavation (Unilock Basic Tech Guide). On a slope we lean to the deep end, because the base also has to resist sliding.
4. Build the bottom restraint first. The low end needs something that will not move: a concrete curb, a buried course of wall block, or the riser of a bottom step set on its own compacted base. Then spike edge restraint into the compacted base along both sides.
5. Give the walk a cross-slope. Pitch the surface about 1/4 inch per foot to one side so water leaves the walk sideways instead of racing down the full length. Where a lot of water comes from above, a swale or drain at the top saves the walk.
6. Screed the bedding layer and lay from the bottom up. A 1-inch bed of coarse sand or chip stone goes on the compacted base, screeded parallel to the slope. Lay pavers starting against the bottom restraint and work uphill, so each course pushes against one that is already locked.
7. Pick a pattern that locks. Herringbone resists creep better than running bond, because the joints never line up in the direction of travel.
8. Compact, then fill the joints. Run the plate compactor over the pavers with a protector pad, sweep in joint sand and compact again. Polymeric sand helps on a slope, but it is not a fix for a base that moves.

How to build steps with pavers on a slope

Paver steps are the answer when the grade is too steep for a comfortable walk. They are built as a series of small, stacked platforms, each on compacted base, not as pavers laid on dirt.

Rise and run

Measure the total drop and the total horizontal distance, then divide it into equal steps. Every riser should be the same height and every tread the same depth. Uneven steps trip people, especially in the dark. Outdoor steps feel best with lower risers and deeper treads than indoor stairs.

Risers and treads

Risers are usually wall block or solid step units, set level on a compacted base and glued to each other with concrete adhesive. Treads are pavers or a single stone slab, such as granite, that overhang the riser slightly. The tread of each step sits on compacted base behind the riser below it.

Landings and the bottom step

On a long run, break the steps with a landing every few steps. The bottom step does the same job as the bottom restraint on a sloped walk, so it gets the strongest base of all. Steps that lead to a door are governed by the building code, so check with your town's building department before you build those.

If you already have steps that are heaving or crumbling, our post on whether front steps should be repaired or rebuilt is the better starting point.

Can a patio be built on sloping ground?

Yes, but a patio must end up close to flat, so the slope has to be dealt with first. There are two ways. On a mild slope, you can cut into the high side and use that soil elsewhere, so the patio sits on undisturbed ground. On a steeper slope, you build a low retaining wall on the downhill side and fill behind it with compacted gravel, never loose topsoil.

The wall is the part that decides whether the patio lasts, so it needs its own base, drainage and backfill. See our guide on building a retaining wall on a slope, our retaining wall services, and how a paver patio is built.

When to call a mason

A short garden path on a gentle grade is a reasonable DIY job. Call a professional when the slope is steep enough to need steps, when water already runs down the yard, when the steps lead to a door, or when a wall is needed to hold the grade.

Gerrior Masonry is an authorized Unilock contractor, and Brussels Block, Beacon Hill Flagstone and granite are common choices for our walkways and steps. You can see finished work on our walkway projects and stairs and steps projects pages, and read more about our walkways and stairs. One customer described a job like this:

"I hired Gerrior Masonry & Landscape of Woburn this past Spring (2015) to rebuild my crumbling front steps and walkway. … They showed up every day and did amazing work. I made a few design changes along the way and they were very accommodating." Kristine B., Yelp review

Common questions

Will pavers slide on a slope?

They will creep if nothing stops them. A fixed restraint at the bottom, edge restraint on both sides, a locking pattern such as herringbone and a well-compacted base keep them in place.

What base should I use for pavers on a slope?

Compacted 3/4-inch crushed gravel, placed in thin lifts and following the slope. Do not use topsoil, stone dust alone or a thin layer of sand.

Should I use polymeric sand on a sloped walkway?

It helps resist washout, but install it exactly to the maker's directions and make sure water can leave the walk sideways. If sand keeps washing out, the drainage or base is usually the real problem.

Do I need a permit for steps or a walkway?

Rules differ by town. Steps to a door and any retaining wall that holds back much soil are the usual triggers, so ask your building department. Dig Safe notice applies to almost any digging.

If you have a sloped yard and want a walkway or steps that stay put, Gerrior Masonry offers free estimates. We are family-owned, fully insured and our work is guaranteed. Call (781) 933-4157 or request an estimate online.