- A little settling in a house's first years is normal. Cracks that keep widening, doors that start sticking and floors that slope mean part of the foundation is moving more than the rest.
- The usual causes are uneven or poorly compacted soil, clay that shrinks and swells with moisture, roof water dumped beside the foundation, and tree roots drying out the soil.
- Settling foundation repair means stabilizing the footing, usually with underpinning, sometimes with steel piers if an engineer specifies them, then fixing the water problem that started it.
- Fix the cause before the cracks. Sealing a settlement crack without dealing with the movement behind it is a patch that will open again.
What a settling foundation actually is
Every house settles a little. The soil under the footings compresses under the weight of the new building, usually in the first few years and usually evenly. That kind of settling is normal and rarely causes more than a few hairline cracks.
The problem is differential settlement: one part of the house sinking more than another. Research from Canada's National Research Council puts it down to soil that compresses unevenly, clay layers of varying thickness, and footings that carry different loads or sit at different depths. When one corner drops and the rest doesn't, the walls, door frames and floors above it have to absorb the difference, and that's when you start to see the signs.
Signs your foundation is settling
Home inspectors look for a pattern, not a single symptom. The classic signs of a settling foundation are:
- Diagonal cracks that are wider at one end, especially wider at the bottom, in a poured concrete wall.
- Stair-step cracks running through the mortar joints of a block foundation or brick exterior.
- Doors and windows that stick, won't latch, or have uneven gaps around them, often on one side of the house.
- Sloping floors, or a marble that always rolls the same way.
- Cracks running from the corners of door and window openings, inside or out.
- A porch, garage or addition pulling away from the main house.
One sign on its own isn't a diagnosis. Doors swell in a humid summer and drywall cracks for plenty of reasons. What matters is several signs together, and whether they're getting worse.
What causes a foundation to settle
- Soil that varies under the house. Firm ground under one wall and softer ground under another means one side compresses more.
- Poorly compacted fill. Fill placed under or beside footings without proper compaction keeps settling for years, and added fill can overload soft soil beneath it.
- Clay that shrinks and swells. Clay soils swell when wet and shrink when dry, so seasons of rain and drought move the footings with them.
- Water dumped against the foundation. Short downspouts and ponding beside the house soften the soil in one spot and leave the rest dry, which is exactly what drives uneven movement.
- Trees close to the house. The NRC's research notes that tree roots are extremely efficient at pulling moisture out of soil, which can shrink clay under a footing.
- Footings at different depths. An addition, porch or garage built on shallower or lighter footings than the house often settles differently from it.
Plenty of ground around Hamilton is clay-rich, from the silt to clayey-silt till under north Oakville to the Haldimand Clay Plain around Caledonia. Soil like that holds water and moves with the seasons, which is why we look at grading and drainage on every settling job.
Settling, bowing or shrinkage? Reading the cracks
Not every crack means the foundation is settling. Here's how the common patterns usually read.
| What you see | Usually means | Next step |
|---|---|---|
| Hairline vertical or diagonal crack, even width, in a poured wall | Shrinkage as the concrete cured. Not structural. | Seal it if it leaks |
| Diagonal crack wider at one end, or stair-step cracks in block or brick | Settlement | Structural assessment |
| Horizontal crack partway up a block wall, wall leaning in | Soil pressure from outside, not settling | Wall reinforcement |
| Sticking doors and sloping floors along with cracks | Uneven movement of the footing | Assessment, possibly an engineer |
A guide, not a diagnosis. Width, direction and whether the crack is still moving all matter.
A horizontal crack with the wall pushed in is a different problem with a different fix. See bowing basement wall repair for that one.
How settling foundation repair works
- 01
Measure and find the cause
We record crack widths and directions, check floors for level, and look at drainage, grading, trees and any additions. If the movement might still be active, it's worth monitoring before deciding anything.
- 02
Bring in engineering where it's needed
Stabilizing a footing is structural work. In Ontario that means a building permit, and underpinning is usually designed from engineered drawings. We coordinate both.
- 03
Stabilize the footing
The settling section gets new support below the old footing, usually by underpinning: digging under it in short, engineered sections and pouring new concrete footings deeper, on firmer ground.
- 04
Fix the water
Whatever started the movement gets dealt with too: drainage we install, plus downspout and grading changes so the soil under the house stops changing from one season to the next.
- 05
Repair the cracks last
Once the footing is stable, the cracks are sealed or reinforced so they stay closed.
Underpinning or piers?
There are two main ways to stabilize a settling footing. Which one fits your house is an engineering call, based on the soil, the load and how far it has moved. Underpinning is our own crew's work. Piers are a specialist install, so if an engineer specifies them for your house, we'll tell you plainly.
| Method | How it works | Where it fits |
|---|---|---|
| Concrete underpinning | Short sections are dug under the existing footing in an engineered sequence and filled with concrete, creating a new, deeper footing | Settling walls and corners, and basements being lowered at the same time |
| Push piers | Steel pipe is driven down hydraulically, using the weight of the house as resistance, until it reaches firm ground | Options an engineer may specify where firm soil is deep |
| Helical piers | Steel shafts with screw plates are turned into the ground, with the installation torque used to confirm capacity | Options an engineer may specify for lighter structures |
Underpinning has a bonus: it can stabilize the foundation and add basement height in the same job. If you've been thinking about a taller basement, read our guide to lowering a basement floor before you decide.
What settling foundation repair costs
Settling repairs vary more than most foundation work, because the fix depends on how much of the foundation is moving. A typical job includes an engineer's visit, usually $500 to $1,500, stamped drawings where underpinning is needed, typically $1,500 to $5,000, and the stabilizing work itself.
Underpinning is priced by the length of wall. Whole-basement underpinning typically runs $350 to $600 per linear foot in the Hamilton area, and a repair to one corner or one wall is a fraction of a full-house job. Structural crack repair afterwards is usually $1,000 to $3,000 per crack. For a side-by-side look at every kind of job, see our foundation repair cost guide.
Typical Hamilton-area ranges before tax. Your price comes from a written, fixed quote after an assessment.
What you can do yourself
You can't stabilize a footing yourself, but you can stop making it worse and keep an eye on it.
- Move roof water away. The Intact Centre at the University of Waterloo recommends extending downspouts at least 2 m from the foundation, and CMHC suggests at least 1.8 m.
- Slope the ground away from the house so rain runs off instead of soaking in beside the wall.
- Keep gutters clear, because an overflowing gutter dumps water in exactly one spot.
- Think about trees. Large trees close to the foundation can dry and shrink clay soil under a footing.
- Monitor the cracks. Mark each end with a pencil line and the date, measure the width, and take a photo with a coin for scale. Check again every month or two.
If your house is less than seven years old
In Ontario, Tarion's new-home warranty includes seven years of coverage for major structural defects, starting at possession, and that coverage includes significant damage from soil movement and major cracks in basement walls. Water getting in through the basement or foundation walls is covered for the first two years.
If your home is still inside those windows, report the problem to your builder in writing first, with photos and dates. If the warranty has run out, or you want an independent opinion before you file, we'll assess it for free and tell you honestly what we see.
Settling foundation questions
Is some foundation settling normal?
How do I know if my foundation has stopped settling?
Do I need an engineer for a settling foundation?
Can you lower the basement while fixing the settlement?
Will sealing the cracks fix a settling foundation?
How AVH fixes settling foundations
Related guides
AVH Foundations works across Hamilton, Burlington, Oakville, Milton, Ancaster, Dundas, Stoney Creek, Waterdown, Cambridge, Brantford, Caledonia and Grimsby.