Concrete driveway subgrade cracking — subgrade

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

1. Check 1

   From the driveway edge, visually map the crack pattern without walking on an unstable section; note whether the crack is isolated, follows a joint, branches, intersects another crack, reaches an edge, or is accompanied by chipped or missing concrete.

   Expected result: The crack is a narrow isolated line with no visible displacement, or it branches, intersects, reaches an edge, and has visible spalling or separated pieces.

   Next step: Photograph the full slab and close views from a safe location, then ask a concrete professional to assess the crack pattern and the condition below it before selecting filler or sealer.

   Stop if: Stop and isolate the area if pieces are loose, the crack edge is sharp, the surface shifts, or the condition creates a trip hazard.

   Why this matters

   Why: Pattern and severity help a professional distinguish a surface symptom from distress that may involve support below the slab. A pattern alone cannot identify a subgrade failure or determine the correct repair.

2. Check 2

   View the slab from its side and from the driveway entrance to compare the visible surface with adjacent pavement, garage threshold, walkway, or curb; note settlement, lifting, rocking-looking sections, or a raised edge without stepping onto the questionable area.

   Expected result: The slab appears level with its surroundings, or one section appears lower, higher, tilted, or separated from the adjoining surface.

   Next step: Keep vehicles and foot traffic off the affected section when safe passage is uncertain, document the boundary, and arrange an in-person pavement assessment.

   Stop if: Do not cross or load a section that rocks, has a sharp step, or appears close to collapse; use an alternate route and obtain professional help.

   Why this matters

   Why: A visible elevation change can indicate movement or loss of support, but it does not show whether soil, base material, drainage, or the slab itself is responsible. The difference may also create an immediate access risk.

3. Check 3

   From dry ground, inspect visible driveway edges and nearby drainage paths for soil washout, sediment, ponding, downspout discharge, or water flowing toward the slab; do not move soil, open the pavement, or conduct a water test.

   Expected result: Water collects near the crack or edge, soil appears washed away, a drain or downspout directs water toward the driveway, or no drainage relationship is visible.

   Next step: Photograph the drainage context during or after a normal weather event only from a safe location, and tell the professional where water collects, exits, or changes direction.

   Stop if: Stay away during flooding, severe weather, or unstable edges; do not enter moving water or attempt to redirect drainage yourself.

   Why this matters

   Why: Water can weaken or erode supporting layers and can accelerate pavement distress, but the same visual sign can have multiple causes. A professional needs to trace the drainage path and evaluate the slab and support together.

4. Check 4

   Observe the crack and surrounding slab over time from the same safe viewpoint, noting new branches, widening appearance, additional settlement, surface breakup, or changes after ordinary wet or freezing weather.

   Expected result: The appearance remains unchanged, or the crack and displacement are visibly progressing or recurring after weather changes.

   Next step: Keep dated photographs and a short observation log for the professional; do not use the log as a substitute for an assessment when the driveway is unsafe or the condition is progressing.

   Stop if: Stop using the section and arrange prompt service if new displacement, rapid expansion, a broken edge, or a sudden change appears.

   Why this matters

   Why: A changing pattern is more concerning than a stable cosmetic mark and may indicate ongoing movement, moisture, or support changes. A stable appearance still does not rule out concealed voids or an older support problem.

5. Check 5

   From the property edge, note whether the cracked area lies in a regular wheel path, near a garage entrance, beside a walkway, or across the only vehicle route, and identify any visible restriction needed to keep people and vehicles away.

   Expected result: The crack is outside normal traffic with no visible trip issue, or it crosses a wheel path, entry, walkway, or route needed for safe access.

   Next step: Use a safer alternate route or keep vehicles off the affected section, communicate the restriction to household members, and provide the access context to the concrete professional.

   Stop if: Do not walk or drive across a section that is displaced, rocking-looking, sharply broken, or otherwise unsafe.

   Why this matters

   Why: Traffic and foot loading can worsen an unsupported or displaced slab, while a sharp or uneven transition can cause a fall or vehicle-control hazard. The access context affects how urgently the area should be isolated.