A new patio is only as good as the strip of grass beside it, yet most patio projects end when the last paver is set and the joint sand is swept in. The ground beside the patio gets whatever is left: spilled base gravel, a few inches of compacted fill, and a hurried row of sod. That strip is where a new patio first starts to look unfinished. Getting it right comes down to two slopes, one height, and an edge you can live with.
How do you transition from a patio to a lawn?
To transition cleanly from a patio to a lawn, three things have to be right:
- the patio falls at least 1/4 inch per foot (2%) away from the house;
- the soil beside it falls at least 6 inches over the first 10 feet (5%);
- the sod finishes level with the paver edge or just below it.
That seam is where hardscape hands its runoff to softscape.
How much slope does a patio need?
A patio within 10 feet of the house should fall at least 1/4 inch per foot, about a 2% slope, away from the foundation. On a paver patio 10 feet deep, that is a drop of about 2.5 inches from the house side to the outer edge.
The International Residential Code’s drainage section, R401.3, is mainly a rule for the soil (more on that below), but it also says hard surfaces within 10 feet of the foundation must slope at least 2% away from the building. Three other sources point to the same 2% minimum:
- ENERGY STAR’s requirements for certified new homes, at 1/4 inch per foot;
- the U.S. Department of Energy’s Building America guidance;
- the paver industry’s construction-tolerance guide, from the Concrete Masonry & Hardscapes Association (formerly ICPI).
Many online guides still give 1/8 inch per foot (about 1%, or 1.25 inches over a 10-foot patio) as an acceptable minimum. Next to a house, that is half the pitch these sources call for. Some state and local codes allow less (Virginia’s allows 1%), so check yours, but 1/4 inch per foot is the safer default. Permeable pavers follow a separate industry guide, which keeps them 10 feet from a foundation unless the foundation is waterproofed and drained.
| Patio depth (house to outer edge) | Minimum drop at 1/4 in per ft (about 2%) |
| 8 ft | 2 in |
| 10 ft | 2.5 in |
| 12 ft | 3 in |
| 16 ft | 4 in |
How much slope does the lawn need for drainage?
The soil beside the house needs more fall than the paving: at least 6 inches over the first 10 feet, about 5%. That is the main rule of R401.3, the IRC’s grading requirement for the ground around a foundation. It is also why the lawn beside a patio should keep falling away from the house rather than leveling off at the patio’s edge.
Don’t mix up the two figures. Some advice applies the 2% paving figure to soil, which leaves the lawn too flat beside the foundation. Beyond the first 10 feet, a gentler, continuous fall is enough, as long as it carries water to a safe outlet and not into a neighbor’s yard.
To check the fall:
- Set one stake near the house and another 10 feet out, in the direction the water should travel.
- Tie a string to the uphill stake at ground level, and level it with a line level.
- Measure from the string down to the ground at the downhill stake.
That measurement is the fall. Next to the house, you want 6 inches or more. For a fuller walkthrough, Right On Sod, the sod and grading company Evan Woods owns in Kitchener, Ontario, publishes a longer guide that walks through the stake-and-string slope check. It covers why to test several paths across the yard, and why runoff from a patio or driveway has to be planned into the lawn’s grade.
How high should the soil sit against the pavers?
Finish the prepared soil about 1/2 to 1 inch below the paver edge, roughly the thickness of the sod, so the new sod ends level with the paving or just below it.
- Purdue Extension’s sod guide puts walks and driveways about 1/2 inch above the prepared soil.
- An older Michigan State University sod guide says about 1 inch.
- The right figure for your yard is the thickness of your sod. Growers cut it with anywhere from about 1/4 inch to 1 inch of soil, so ask your supplier.
“We stop the soil about half an inch to an inch under the paver edge, so the sod finishes flush with the stone. Set it high and the mower scalps that edge and water runs back onto the patio. Set it low and you get a sunken strip that dries out and collects runoff.” — Evan Woods, owner of Right On Sod
That edge strip has a harder start than the rest of the lawn. Purdue’s turf program notes that the soil within a foot of pavement is often only 2 to 3 inches deep and takes extra heat from the paving. Beside a paver patio, the first 6 inches or so of “lawn” may sit on gravel, because paver guidelines run the patio’s compacted base about 6 inches past its edge restraint.
What should go around the edge of a patio?
For the least upkeep, use a mow strip set level with the lawn. For the cleanest look, lay the sod tight to the stone. Here is how five patio edges and borders compare:
| Edge | Look | Mowing | Upkeep |
| Sod laid tight to the paver edge | The cleanest line, with no visible border | The mower runs along the stone | Cut the grass back from the paving with an edger when it starts to creep over the stone |
| Mow strip: a band of pavers, brick, or concrete set level with the lawn | A crisp frame. About 8 in is common for a poured strip; make it 12 to 14 in if it doubles as a path | One wheel rides on the strip, so there is little trimming | Masonry can heave in freeze-thaw winters; reset any units that lift |
| Steel or aluminum edging | A thin, crisp line | Set the top about 1/2 in above the finished soil grade, low enough for the mower to pass over it | Illinois Extension rates metal the most durable edging. Steel costs more and can frost-heave, so stake it well and check that the exposed edge isn’t sharp |
| Gravel strip | A loose, informal border | Needs an edge at least 3 in above grade to hold the stone, so the mower can’t cut right up to it | Without that edge, gravel drifts into the lawn; trim along it after mowing |
| Planted border | The softest look; suits curves | Mow along it | Grass creeps into mulched beds; re-cut the edge once or twice a year |
Whichever you choose, keep the lawn side of the edge low enough for the mower to ride along it or pass over it. Our post on mailbox landscaping ideas gives the same advice for a stone border: set the first course slightly below grade, or the mower clips it. A raised border, one of the styles in our patio paver edging ideas, frames a patio handsomely, but its lawn side needs trimming after every mow.
Step by step: finishing the lawn after the patio crew leaves
“Behind most new patios, we find two or three inches of soil sitting on base gravel, packed hard by wheelbarrows and equipment. Lay sod on that and the edge row is the first thing to brown. That strip gets rebuilt before any sod goes down.” — Evan Woods
- Finish the patio first. Its edge restraint must be in place before the lawn goes in. The paver industry is clear that soil backfill never holds pavers in place, and ordinary lawn edging doesn’t either.
- Watch where the water goes. Run a hose on the patio, or watch it in the next rain. Water should leave by the outer edge, never the house side.
- Clear the strip. Rake out loose gravel, sand, and construction debris, but leave the patio’s compacted base where it is, because it holds the edge restraint.
- Check the lawn’s fall with the stakes and string.
- Rebuild the soil. Loosen compacted ground and add topsoil, with compost worked into the top few inches, including over the base gravel at the edge.
- Set the height and firm it. Fine-grade so the soil sits 1/2 to 1 inch below the paver edge. Firm it until a footprint sinks no more than 1/2 inch, then moisten it before laying.
- Lay the first row along the patio. Use a straight patio edge as your starting line, with full pieces against the stone. Put trimmed pieces on the inside, and don’t use any narrower than 9 inches or shorter than 18 inches. Stagger the seams like brickwork, push the edges tight without stretching, and cut the sod snug to the paving.
- Roll, water, and protect. Roll lightly to press the sod onto the soil, and water within 30 minutes to an hour.
- Then water at least once a day, more often in hot weather, until the sod roots, usually 10 to 14 days.
- Give the edge rows extra water, because they dry out first.
- Keep foot traffic off for three to four weeks, and mow slightly higher than normal at first.
Patio drainage options when slope isn’t enough
If the yard tilts toward the house and can’t be regraded, or the patio has nowhere to shed water, grading alone won’t fix it. Where lot lines or walls rule out 6 inches of fall, the IRC calls for a swale or a drain to carry the water away. A swale is a shallow, grassed channel at the surface; a French drain moves water underground. Our guide to how proper site grading prevents water damage explains why a drain can’t always make up for a yard graded the wrong way. Plan either one before the sod goes down, not after.
