How Permanent Pothole Repairs should be carried out!

UK Pothole Repair On-Site Checklist

 1. Initial Assessment

Identify size and depth of pothole.

Check for:

Standing water

Cracking around the area

Base/sub-base failure (soft spots)

 If base failure is present → plan full-depth repair, not just patching

 2. Cut Out the Defect:

Saw cut to regular shape (square/rectangle).

Ensure vertical edges.

Remove all loose/damaged material.

 UK guidance: Avoid “feathered edges” — they fail quickly.

 3. Excavate to Sound Layers:

Remove material until structurally sound layer reached.

Typical depths:

Small pothole: 40–100 mm

Structural failure: 150 mm+

 4. Reinstate the Base (if needed):

Replace with Type 1 sub-base (MOT Type 1 aggregate).

Compact in layers.

 This aligns with UK Specification for Highway Works (SHW).

 5. Dry and Clean

Remove:

Water

Dust

Loose debris

Slurry from saw cutter

 Use compressed air / heat lance if needed

 6. Apply Tack Coat

Bitumen emulsion on:

Base

Vertical edges

 Mandatory for permanent repairs under UK best practice.

 7. Lay Asphalt (Correct Material)

Choose based on road type:

Hot Rolled Asphalt (HRA) → traditional UK roads.

Dense Bitumen Macadam (DBM) → structural layers.

Stone Mastic Asphalt (SMA) → high-traffic surfaces.

 Follow local authority spec (varies slightly).

 8. Layer Thickness:

Lay in compacted layers (max ~75 mm each).

Build up to match existing road level.

 9. Compaction.

Use:

Plate compactor (small repairs)

Roller (larger areas)

 Must achieve full compaction — no movement under load.

 10. Finish Level.

Slightly proud before final compaction.

level = flush with surrounding surface.

 11. Seal Edges:

Apply bitumen sealant around joints.

 Prevents water ingress (critical in UK climate).

 12. Reopen to Traffic.

Only when material is:

Stable.

Properly compacted

 UK Standards & Expectations.

 Key Documents

Specification for Highway Works (SHW).

Well-Managed Highway Infrastructure Code of Practice.

HAUC reinstatement guidelines.

 Typical Performance Expectations

Permanent repair should last years, not months.

No:

Rocking under traffic.

Fretting (loose aggregate).

Edge cracking.

 When You MUST Do Full-Depth Repair.

Do NOT just patch if:

Pothole keeps reappearing.

Area feels soft or “pumping”.

Cracks extend beyond repair area.

Drainage is poor.

 In these cases, surface patching = guaranteed failure.

 UK-Specific Reality (Important).

Because of frequent rain and freeze–thaw cycles:

Water control is more important than material quality.

Edge sealing and drainage often determine success.

 Quick “Site Rule of Thumb”

If you remember nothing else:

Clean → Cut → Dry → Bond → Compact → Seal