Patio settlement

That specific version of it, yes — more than the settlement itself. A patio that has dropped in the middle of the yard is an appearance and furniture-wobble matter. A patio that has tilted back towards the house has become a system for delivering rainwater to your foundation.

So the first thing worth establishing is not how much it has settled, but which way it now falls.

What it is

Patios are commonly poured directly against the house, often over backfill that was placed when the house was built. That backfill continues to consolidate, and because it is deepest against the wall, the settlement is frequently greatest there — which is exactly the direction that reverses the fall.

A patio was almost certainly built with a slight fall away from the house. Losing that fall does not take much movement: a quarter-inch over a few feet can be enough to flatten it, and a little more reverses it.

Patios also tend to be large and lightly reinforced compared to a driveway, so settlement often shows as a broad dish rather than a step, and the concrete frequently remains in one piece.

What seeing this cannot establish

• The amount of settlement does not indicate whether water is now going the wrong way. A small movement on a patio built with minimal fall matters more than a large movement on one built with generous fall.
• Water arriving at the wall does not establish that water is entering the basement, and a dry basement does not establish that the fall is acceptable.
• Whether a void exists beneath cannot be confirmed from the surface, which matters because lifting a large patio with a large void is a different job from lifting one that has simply tilted.

What this can be associated with

Candidate explanations, not findings. Nobody can establish which applies to your concrete without seeing it.

• Foundation backfill consolidating beneath the patio, deepest against the house and therefore settling most there
• Roof water discharging onto or beside the patio, which can move base material
• Soil moisture cycling in clay-rich ground beneath a large, lightly loaded slab
• Base material that was thin or placed over topsoil or organic material at construction
• A patio poured tight against the house with no isolation, so movement transfers rather than relieving at a joint

What you can safely check yourself

• Put a level on the patio in several places, working outward from the house, and photograph each. This is the observation that matters most on this page.
• Failing a level, pour a bucket of water near the house edge and watch where it goes. Photograph it. Water that runs towards the wall is the finding.
• Look for a gap where the patio meets the house, and note whether it is open enough to take water down beside the foundation.
• Tap across the patio and compare the sound in the settled area to elsewhere.
• Check whether the slab is in one piece or has cracked across the dished area.
• Note where downspouts discharge relative to the patio, and photograph in rain if you can.

When this is frequently cosmetic

• A patio that has settled slightly but still falls away from the house and drains freely
• Localised dishing away from the building that ponds briefly and dries

When professional evaluation matters more

• The patio now falls towards the house, or water ponds against the wall
• There is an open gap between the patio and the house taking water down
• The basement or crawl space has become damp, or shows efflorescence, on the wall behind the patio
• The settlement has increased between dated observations
• The slab has cracked across the settled area rather than dishing in one piece

When replacement enters the conversation

• The slab has broken up rather than moved as a unit
• The surface is deteriorating as well as settled
• The required change in fall is more than lifting can reasonably achieve across the area
• The patio was poured over unsuitable material and the base itself needs rebuilding

Evidence worth having before you ask for estimates

Every item here is something you can produce without tools or risk, and every one of them makes an estimate more accurate.

• Level readings at several points, photographed, working out from the house
• A water test photograph showing which way it runs
• A photograph of the patio-to-house joint
• Photographs of the interior wall behind the patio, including any efflorescence or damp
• Downspout locations and discharge points

Questions to ask whoever comes out

• What fall are you aiming to restore, and how will you check you have achieved it?
• Can lifting achieve that fall across this area, or is it beyond what lifting does well?
• What will you do about the joint where the patio meets the house?
• Does the roof drainage need changing for this to hold?
• If the patio is lifted, what happens to any steps, thresholds or door clearances it meets?

Where estimates for this commonly differ in scope

These are the places two prices for apparently the same work stop being comparable.

• "Levelling" a patio can mean making it flat or restoring a deliberate fall. Those are different targets and only one of them keeps water off the house.
• The joint at the house is frequently excluded from both lifting and replacement estimates, despite being the water path that matters.
• Door thresholds and step risers change if the patio height changes. Estimates vary on whether adjusting them is included.
• Drainage correction outside the slab is a separate trade in some proposals and included in others.

Who tends to do this work

• A concrete leveling specialist
• A drainage contractor or landscaper who does grading
• A residential flatwork concrete contractor

ConcreteOwner does not inspect, certify or approve contractors. This describes which trade usually holds this work, not a recommendation of anybody in particular.