Grading and Slope Around a Foundation
The first ten feet of dirt around your house is a drainage system with no moving parts and no power bill. When it stops working, everything downstream of it has to work harder, and eventually something below grade gives.
- Grade measured at every corner, free within 48 hours
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- 20+ of Chicago lots, 1,500+ homes served
Regrading: 5-year warranty
The short answer
The long-standing residential convention is roughly six inches of fall in the first ten feet away from a foundation, about a five percent slope. Ground that has settled flat, or tipped back toward the wall, delivers every storm straight to the footing. Rebuilding that fall runs $600 to $2,500 on most Chicago lots.
Slope decides whether rain becomes runoff or becomes seepage. Ground falling away from the wall carries water out toward the lawn while it is still on the surface. Ground that has gone flat lets the same rain stand and soak in at the one place the soil is loosest, directly above your footing. No pump, membrane or pipe in the whole trade returns as much dry basement per dollar as the first ten feet of correctly shaped dirt.
Two local habits work against that. Builders in this region backfill with the heavy clay they just dug out, and clay keeps consolidating for years, so a lot that graded correctly at closing is often flat by the time a second owner arrives. Then planting beds get built up against the siding and topped with mulch, which looks tidy and holds rain against the wall like a sponge. We see both on nearly every street. The yard drainage hub covers the rest of the system.
How much slope should the ground around a foundation have?
Roughly six inches of drop across the first ten feet is the convention the residential trade has used for decades. It is a rule of thumb worth keeping, not a code citation, and past ten feet the ground only has to keep heading the same direction.
Here is how we measure it on a real lot, using tools you can borrow from a neighbor.
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Set a level reference
Drive one stake at the wall and another ten feet out, run a string between them and hang a line level on it. Level the string at the wall end. The distance from string to ground at the far stake is the fall you actually have.
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Read it at every corner
Grade fails in patches rather than evenly. Take a reading at each corner and at the middle of every long wall, then write them on a sketch of the house. The damp spot inside almost always lines up with the worst number outside.
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Look hardest at the first three feet
Soil right against the wall does most of the work. If those first steps run flat or tip back, rain pools over the loosest fill on the property and the seven feet of decent slope beyond them never get anything to carry.
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Rebuild with fill that sheds
Fall is built with compacted clay-heavy fill, not with topsoil and never with mulch. Loose organic material parks water where you least want it. The shedding layer goes down first, and anything decorative sits on top of a grade that already works.
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Leave the foundation showing
Keep several inches of foundation exposed above the finished grade. Burying siding, brick weep holes or a sill plate to win a little slope trades a wet basement for rot and an easy path in for insects.
Best for
- Any house where the beds have crept up the siding
- Post-war lots flattened by sixty years of settlement
- The repair to try before buying any drainage system
- Doing at the same time as downspout work, since it is the same water
- Carries our 5-year warranty when our crew does it
What it will not do
- It cannot lower a water table or dry out saturated clay
- Fresh fill consolidates, so plan on topping it up in year two
- Walks and patios pitched at the house are a separate problem
What happens when the ground slopes toward the house?
Reversed grade does more than make a puddle. It loads the wall, and that load is what turns a damp corner into a structural estimate.
The failure runs as a sequence, and most houses show clearly which stage they have reached.
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The fill stays wet
Water standing on flat ground sinks into the backfill and cannot spread sideways through clay. The ring of fill around the foundation behaves like a tub that every storm refills and only evaporation empties.
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Clay swells against the wall
Saturated Chicago clay expands, and the only direction that expansion can go is sideways into the foundation. The wall then carries a lateral load nobody designed it to hold for weeks on end.
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Mortar joints give first
Joints are the weak line in a block wall. Pressure shows up as a horizontal crack partway up the wall, a stair-step running toward a corner, or a top course that has started to lean into the room.
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Water finds the cove
The same pressure pushes water through the seam where the wall meets the floor. Seepage at that seam is usually what a homeowner notices first, and it shows up long before anything looks structural.
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Freeze and thaw finish it
Wet clay expands again when it freezes. Across one Illinois winter that cycle lifts stoops, tips walks back toward the house and widens whatever the summer pressure opened.
Signs you are on this path
- A dark damp band along the base of the wall after every rain
- Seepage at the same cove joint storm after storm
- Mulch or soil sitting above the bottom edge of the siding
- A walk or patio that has tipped back toward the house
- Efflorescence blooming on the same block each spring
When it stops being a drainage job
- A horizontal crack running across a block wall
- A wall bowed at mid-height or leaning in at the top
- Stair-step cracks that open further every season
Is regrading enough, or do you need buried drainage?
Surface work and buried work solve different halves of the same problem. Put them side by side and most houses land clearly on one side of the line.
| Regrading and surface work | Buried drainage systems | |
|---|---|---|
| What it changes | Where rain goes during the first ten feet | Where water goes once it is already in the ground |
| Published cost | $600 to $2,500 with downspout work included | French drain $45 to $90 per foot, drain tile $95 to $160 |
| Disruption | Soil, sod and planting beds along the wall | A trench outside, or the slab edge opened inside |
| Season | Spring through late fall | Exterior stops at frost, interior runs all year |
| What it cannot do | Lower a high water table | Stop rain that lands and stands against the wall |
| Evidence it is the right call | Flat or reversed grade, wet only after storms | Correct fall outside and the wall still wets |
| Effect on the wall | Removes the load before it can build | Relieves water that already reached the footing |
| Order of work | Always first | After the surface has been dealt with |
| Our warranty | A 5-year warranty on the work | A lifetime, fully transferable warranty on interior systems |
A grade fix is not a consolation prize. On a real share of the houses we inspect it is the whole repair, and we would rather sell that than a system nobody needed. Where the wall has already taken damage, read bowing basement walls before spending anything on dirt.
Want to know what your grade actually measures? We shoot the fall at every corner and hand you the numbers in writing, free within 48 hours.
How grade fails on each era of Chicago house
Every era gets the same physics and a different starting condition. These four cover most of the lots our crews walk in a week.
Pre-war bungalows and two-flats
Stone and early concrete foundations on narrow lots, where the gangway is a concrete strip that a century of frost has tipped back toward the house. There is rarely enough open soil left to build any fall into.
Fix the walk, not the dirt
Post-war block ranches
The classic case. Grading was right the year the house was built, the backfill has consolidated ever since, and decades of mulch raised the beds. Block walls also punish standing water faster than poured walls do.
Best payoff of any era
1980s and 90s poured wall homes
Deeper backfill, sharper original grade, and often a walkout door or a window well cut into the slope. Water concentrates at those cuts instead of spreading evenly along the wall.
Grade toward the cuts
Newer subdivision homes
Engineered lot grading with shallow swales carried between properties. Fences, sheds, raised beds and pools interrupt those swales, and the water reroutes to whichever foundation sits lowest.
Find the broken swaleWhat does regrading cost around a Chicago house?
Regrading and downspout work is published at $600 to $2,500. That is the published range we quote from whether the job is one settled corner or the whole perimeter.
| Work | Range | What moves the number |
|---|---|---|
| Downspout extensions and regradingtypical job | $600–$2,500 | Feet of grade to rebuild, soil hauling |
| Exterior French drainper linear foot | $45–$90 | Trench depth, where the water can legally go |
| Interior drain tileper linear foot | $95–$160 | Length of the run, slab thickness, what has to be moved off the walls |
Hardscape is the one variable we cannot put in a table. A walk or patio pitched back at the house belongs to the trade that owns it, and we write that in the report rather than pricing around it. Every range above is published on the cost page.
When adding soil is the wrong move
Grade is the first thing we measure and frequently the only thing that needs changing. These are the cases where more dirt solves nothing.
The fall already measures correct
When every corner reads right and the wall still wets during a slow three-day soaker, water is arriving from below rather than from the surface. Rain-only leaks against constant seepage separates the two patterns in one wet week.
Look below, not aboveThe water arrives from next door
Illinois law broadly protects the natural flow of surface water between properties, but the details vary by municipality and by what has been built since. Ask your village how they handle it, and if a neighbor has actively redirected water at you, that conversation belongs with an attorney.
Village, then attorneyIt is the walk, not the yard
A slab tipped back at the house is a hardscape problem, and packing soil against its edge only dams the water in place. Driveway, patio and window well drainage lays out the options, several of which cost less than a weekend of your own time.
Different tradeOne low corner and a few bags of fill
A single settled spot under one downspout is a homeowner job. Buy clay-heavy fill, build the fall by hand, tamp it, seed it and watch that corner through a spring. If the basement stays dry, you are finished and we were never needed.
Do it yourselfQuestions homeowners ask about grading and slope
How much fall does the ground need around a house?
The convention most of the residential trade works to is about six inches of drop across the first ten feet, which is roughly a five percent slope. Treat it as a target rather than a legal threshold. What matters more is that the ground keeps heading the same direction past that ten feet, because fall that ends in a flat bed or a low corner just moves the standing water a short distance from the wall.
Can I just add topsoil against the foundation?
Topsoil is the wrong material for the job. It is loose and organic, so it absorbs rain and holds it exactly where you were trying to shed it. Build the fall with compacted clay-heavy fill and put topsoil or mulch on as a thin finish layer only. Compaction matters as much as the material: loose fill of any kind settles back to flat within a season or two.
How close to the siding can the soil sit?
Leave several inches of foundation showing above the finished grade. Soil or mulch piled against siding keeps wood permanently damp, blocks the weep holes in brick veneer and gives insects a covered route into the framing. If you cannot build fall without burying the siding, the answer is to remove material farther out rather than to add more at the wall.
Will regrading alone fix a wet basement?
Often, and we say so when the evidence points that way. If the basement wets only during heavy rain, the damp patch sits below a settled corner, and the grade measures flat or backward there, surface work is a genuine candidate for the whole repair. If the wall weeps through a slow soaker with no downpour, the water is coming from the water table and no amount of soil will change that.
How long before new grading settles again?
Expect the most movement in the first year, which is why we compact in lifts rather than dumping and raking. Plan to walk the perimeter the following spring, top up anything that has dropped and reseed. Grade is maintenance, not a permanent installation. Checking it every couple of springs costs nothing and catches the slow reversal before your basement does.
Do I need a permit to regrade my yard?
Simply reshaping soil near the house usually does not, but the answer is local. Some Illinois municipalities regulate any change to an approved lot grading plan, especially in newer subdivisions where swales carry water between properties, and some have stormwater rules that apply once you move volume around. Call your village before the work starts. A five-minute phone call beats a correction notice.
Water still sitting out in the yard?
Grade at the wall and grade across the lot are different questions. A house can shed rain perfectly for ten feet and still sit beside a lawn that holds water for two days, which keeps the soil saturated and gives the next storm nowhere to drain. If that describes your yard, start with the standing water instead.
Read the standing water guide
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