Concrete driveway subgrade settling — subgrade

Use only checks that match the exact appliance or system and its official guide.

1. Check 1

   From the driveway edge or another stable ground position, photograph and outline the settled area relative to the garage, street, property edge, joints, and nearby structures. Do not step onto a broken or visibly moving slab just to mark its center.

   Expected result: The depression is isolated, follows a joint or edge, spans a wheel path, extends across multiple panels, or cannot be approached safely.

   Next step: Keep the photos and a simple sketch, restrict traffic over the affected section, and provide the location to a concrete or geotechnical professional.

   Stop if: Stop entering the area if the slab shifts, an edge is undermined, a void is visible, the surface is slick, or documenting it would require crossing an unsafe section.

   Why this matters

   Why: The pattern helps a professional understand the extent and whether movement is localized or distributed. It cannot reveal the depth or condition of the subgrade without appropriate assessment.

2. Check 2

   Look across the surface for crack and joint patterns without probing or widening them: note diagonal cracks from corners, intersecting cracks, open joints, vertical offsets between panels, spalled edges, or a low area with no visible cracking.

   Expected result: Cracks are tight and stable-looking, widening or offset, concentrated at a corner or joint, accompanied by broken concrete, or absent despite visible settlement.

   Next step: Photograph the pattern with a nearby fixed reference and note whether it changes over time. Do not fill, seal, grind, cut, or patch the cracks before professional assessment if settlement is suspected.

   Stop if: Stop if an edge is sharp or loose, a void is open, concrete is crumbling under normal observation, or any measurement would require contact with an unstable slab.

   Why this matters

   Why: Crack pattern and vertical offset can indicate different forms of distress or loss of support, but they do not establish whether the cause is subgrade, drainage, frost, load, or concrete material condition.

3. Check 3

   After ordinary rainfall has ended and the area is safe, observe where water rests or flows around the depression, joints, driveway edge, downspouts, and nearby soil. Do not dig, probe the subgrade, remove concrete, or enter a saturated area.

   Expected result: Water drains normally, pools in the settled area, stains or erodes a joint or edge, appears near a downspout or utility route, or the ground remains soft after rain.

   Next step: Record rainfall timing, water locations, and any change in the depression. Keep runoff from being deliberately directed into the area and give the observations to the professional.

   Stop if: Stop if the surface becomes slippery, soil is undermined, water exposes a hole, a utility feature is damaged, or observation requires excavation or entering standing water.

   Why this matters

   Why: Water movement can weaken support or carry fine material away, but the visible route does not prove the underground cause. Persistent ponding or erosion raises the priority of drainage and subgrade assessment.

4. Check 4

   Inspect the driveway perimeter and visible transitions from ground level: look for a separated edge, a sunken utility patch, a gap at the garage threshold, displaced soil, tree-root uplift nearby, or a change where fill meets undisturbed ground.

   Expected result: The settlement is near a utility patch, driveway edge, garage, tree, recent trench, or other transition, or there is no visible transition clue.

   Next step: Photograph the transition and note construction, utility, landscaping, or drainage history. Have the professional coordinate any utility or structural investigation before disturbance.

   Stop if: Stop if soil is collapsing, a utility cover is unstable, a trench or void is exposed, or the inspection would require lifting, digging, cutting, or moving heavy material.

   Why this matters

   Why: Transitions and buried routes can be associated with uneven support or water movement, while an absent clue does not rule out concealed causes. Do not infer a repair method from the nearest visible feature.

5. Check 5

   Record progression and use history without load testing: when the low area first appeared, whether it changes after wet or freeze conditions, whether vehicles have crossed it, and whether any nearby wall, garage, walkway, or drainage feature has changed.

   Expected result: The condition is stable, slowly progressing, rapidly changing, associated with water or seasonal weather, or accompanied by a new trip or vehicle hazard.

   Next step: Keep a dated photo record, restrict unsafe use, and arrange high-priority professional assessment. Do not attempt to level, support, demolish, cut, or conceal the affected slab.

   Stop if: Stop use and isolate the area immediately if movement accelerates, a void opens, a vehicle could lose stability, or the driveway threatens an adjacent structure or public path.

   Why this matters

   Why: Time and environment help the professional prioritize soil, water, freeze, fill, or load-related questions. Rapid movement or a new safety hazard should not wait for a cosmetic repair decision.