Most settling advice is a list of ten tips with no hint of which ones matter. So people buy a rain barrel and leave the downspout dumping onto the stoop.
This plan is ranked, from the jobs that do the most for the least money and effort down to the ones that only matter in certain yards. It's written for Green Bay ground: slow-draining red clay, loose backfill along the house, and about 152 days a year with a low at or below freezing. For the reasons behind each item, read why concrete settles.
The Honest Starting Point
You can't change the soil: much of Brown County is clay-rich glacial till and old lake clay that holds water and is prone to frost heave. You can't change the weather, which Green Bay's 1991–2020 normals put at about 31.6 inches of precipitation a year, including roughly 55 inches of snow. And the backfill, trenches, and base under each slab are already in the ground.
What you can control:
- Where water lands.
- How fast it leaves.
- Whether it gets under the slab.
- How much weight sits on slab edges while the ground is soft.
Every item below works on one of those four.
The Priority Matrix
| Task | Impact on settling | Effort | Relative cost | DIY? | Best time |
|---|---|---|---|---|---|
| Extend downspouts past every slab | High | Low | Low | Yes | Whenever the ground isn't frozen |
| Redirect the sump discharge | High | Low to moderate | Low | Usually | Before the spring thaw |
| Fill washed-out slab edges | Medium to high | Low | Very low | Yes | Spring or fall |
| Seal joints and the gap at the house | High | Moderate | Moderate | Yes, or hire it | Late summer to early fall |
| Regrade soil away from the house | High | Moderate to high | Low to moderate | Yes, or a landscaper | Spring or fall |
| Keep gutters flowing | Medium | Low | Low | Yes, or hire it | Late fall and spring |
| Keep heavy loads off edges | Medium | Low | Free | Yes | Especially March to May |
| Manage trees and roots | Varies | Varies | Varies | With an arborist | When planting or before cutting |
| Build drainage and compaction into a new pour | Highest for new concrete | Done once | Part of the job | No | Before the pour |
Sorted into four boxes:
| Low effort | Higher effort | |
|---|---|---|
| High impact | Do this weekend: downspouts, sump line, edge washouts | Plan for it this year: joint sealing, regrading |
| Lower or situational impact | Make it a habit: gutters, loads, snow piles | Only if it applies: trees, new pours |
Do This Weekend: Water at the Source
Downspouts
Every downspout should end at least 6 feet from the foundation (10 is better), past the far edge of any slab, on ground that slopes away. Water dumped onto a slab just finds the other side of it.
Make a quick downspout map: walk the house and, for each downspout, note which slab sits within 6 feet of where it empties. Those slabs are the most likely to sink next. Our guide on how to extend downspouts covers which extensions survive a Wisconsin winter, and why downspout extensions matter makes the case for them.
Sump discharge
A sump pump runs hardest in spring, exactly when the soil under your slabs is softest. An outlet beside the driveway or patio soaks that soil over and over. Move it onto lawn that slopes away, keep it off public walks, neighbors' yards, and the sanitary sewer, and check your municipality's rules before rerouting.
Washed-out edges
Walk every slab edge looking for a gap or small trench where soil has dropped or washed away.
- Shallow gap: pack in soil with some clay in it, tamp it, and seed it. Finish just below the slab surface, sloped away, so water runs off the concrete onto the lawn.
- Skip sand, gravel, and mulch against the slab. They let water soak straight down to the base.
- A tape measure slides more than an inch or two under the slab: that's a void, and packing soil from the side won't fill it. See voids under concrete.
Plan for It This Year: Seal and Grade
Seal joints and the gap at the house
An open joint is a funnel into the base, and the gap where a slab meets the foundation sends runoff straight into the loosest soil on your property.
- Use a flexible sealant made for concrete joints, with closed-cell backer rod in deep joints. Rigid patch cracks out by spring. See best concrete crack caulk.
- Seal on a dry day at 40°F or warmer, on frost-free concrete. Around Green Bay that usually means late summer into early October. October's normal low is about 39.5°F.
- Never seal an offset joint. One side is lower because its support is gone, and sealing locks in the drop. Lift first, then seal.
- Check it every year. Sealant wears out, fastest in full sun.
More in why caulk concrete joints and caulking where concrete meets the house.
Grade the soil away from the house
Foundation backfill settles, so a yard that sloped away the year you moved in can go flat or even tip back. The national model residential code calls for at least 6 inches of fall in the first 10 feet from the foundation, and for paved surfaces within 10 feet to slope away at least 2%.
Check it in five minutes: drive a stake 10 feet out from the wall. Tie a string at the base of the wall, run it to the stake, level it with a line level, and measure from the string down to the ground at the stake. You want at least 6 inches.
Worked example: a 40-foot wall where the soil runs dead flat. A wedge 6 inches deep at the wall, tapering to nothing 10 feet out, averages 3 inches over 400 square feet. That's 100 cubic feet, just under 4 cubic yards: one small delivery and a long Saturday with a wheelbarrow. Use soil with some clay in it, not sand or mulch, and keep it below the siding.
Where a slab touches the house, the slab is part of the grade. If it tips toward the wall, soil won't fix it; it needs lifting. More in soil grading around concrete.
Make It a Habit: Gutters, Weight, and Snow
Keep gutters flowing
A clogged gutter spills over along its whole length and drops water right at the base of the wall, where your downspout extensions can't help. Clean gutters after the leaves fall and again in spring. See gutter cleaning to protect concrete.
Keep heavy loads off edges during the thaw
Residential flatwork is usually about 4 inches thick, and its edges and corners are its weakest spots. When the soil under it is soft, a heavy load near an edge can push it down.
Borrow WisDOT's playbook. The state posts spring weight limits on many roads while frost comes out, on average from about March 9 to May 9. Give your driveway the same break:
- Schedule heavy deliveries outside the thaw: roll-off dumpsters, landscape stone, moving trucks.
- Keep wheels toward the middle. Park campers and trailers on the center of slabs, not at edges or apron corners.
- Spread the load. If a dumpster has to sit on the driveway, ask for boards or plywood under its rails.
Pile snow on the lawn
Snow pushed against slab edges and the foundation melts exactly where you don't want it. Pile it on the lawn, downhill from the house. More in winter concrete care.
Only If It Applies: Trees and New Pours
Trees
Tree roots commonly reach two to three times as far out as the branches. A tree can push slabs up while it's alive and let them drop after it's gone.
- Planting: Iowa State Extension recommends at least 10 feet of rooting room for large shade trees, and lists maples (Norway, red, sugar), ash, poplars and cottonwoods, willows, and American elm among trees with abundant surface roots.
- Existing trees: don't cut roots more than about 2 inches thick without an arborist's OK. Root barriers need to go at least 18 inches deep, and Wisconsin law requires a Diggers Hotline (811) call at least three working days before you trench.
- After a removal: rotting roots leave voids, so watch nearby slabs for the next few years. See tree roots lifting concrete.
New pours
Prevention is cheapest before the concrete goes down. We don't pour concrete, but these are the questions we'd ask the contractor who does:
- Will you strip topsoil, sod, and roots before building the base?
- How will you compact the subgrade and gravel, and in what layer thickness? The model code's floor-slab rule (fill free of vegetation and debris, compacted for uniform support) is a fair benchmark.
- Where does water in the base go? On clay, a gravel base with no outlet can hold water like a tub.
- Is there a fresh trench or new backfill under it? Pouring over either without compacting it invites a dip.
- Will you pour on frozen ground? You shouldn't, and fresh concrete needs protection from freezing for its first couple of days.
More in pouring new concrete in Wisconsin and questions before replacing concrete.
The Yearly 10-Minute Check (Do It in the Rain)
A dry-day inspection hides the one thing that sinks concrete. Do this one during a steady rain in September or early October, while there's still time to caulk and lift before freeze-up. No rain coming? Feed a garden hose into the bottom of each downspout, then run it along the slabs. Bring your phone, a tape measure, and an umbrella.
| Minutes | Check | Pass | Fail, and what to do |
|---|---|---|---|
| 0–3 | Stand at each downspout and the sump outlet for 30 seconds | Water flows 6+ feet out, across lawn, away from slabs | Water hits a slab edge, pools, or runs back. Extend or redirect it this week |
| 3–5 | Look up at the gutters (in real rain) | Water goes down the downspouts | Sheets of water over the edge. Clean the gutter |
| 5–7 | Watch slab edges and the gap at the house | Water runs off the concrete onto the lawn | Water vanishes under a slab or into the house gap. Seal it, or check for a void |
| 7–9 | Measure your three benchmark joints | Same reading as last year | Any new drop. Go to the response plan below |
| 9–10 | Photograph each benchmark from the same spot | Photos saved with the date |
Setting up benchmarks: the first year, pick the three joints most likely to move: the stoop, the apron at the garage door, and the slab nearest your worst downspout. Put a paint-marker dot at each, lay a straight board across the joint, measure the gap, and write it down. Measure the same dots every fall; frost shifts slabs in winter, so don't compare a February reading to a fall one. Our frost heave vs. settling guide has a seasonal log.
The Moment You See the First 1/4": A Response Plan
A quarter inch is where accessibility rules for walking surfaces stop allowing a plain vertical edge, and it's a good trigger at home too. The void underneath is still small.
| When | What to do |
|---|---|
| Day 1 | Measure it, mark the spot, and photograph it with the tape standing in the frame. Note the date. |
| Week 1 | Find the water: a downspout, sump outlet, gutter overflow, open joint, or low spot within about 10 feet. Fix it. Run a hose at the slab edge for a minute; water that disappears under the slab means a void. |
| If it's winter | Write it down and wait. Frost can make a slab look higher or lower than it really is. Re-measure in late May. |
| This season | Fill edge washouts. Seal joints that are still level. Leave the offset joint alone. |
| By next fall's check | Still 1/4", water fixed, no hollow sound: keep watching. Grown to 3/8" or more, sounds hollow, tips toward the house, or reached 1/2" on a walk: book a lift. |
What to skip at this stage:
- Don't caulk across the drop. It seals in the low side.
- Don't grind the lip on a slab that's still moving. You'll be grinding again next year.
- Don't pour sand or pea gravel into the gap. It washes out and gives water a path in.
If you do end up lifting, early is the easy version: a smaller void, a slab still in one piece, and less chance of cracking on the way up. We can seal the joints the same visit. See why fix sunken concrete now.