Kerbstone installation method statement: what ADQCC 7.5 requires in Abu Dhabi
Kerb method statements come back with comments for the same handful of reasons: vague acceptance criteria, a missing pre-haunching inspection, and values copied from an old project. Here is what a consultant expects to see, step by step.
Kerbs look like the simplest activity on a road or hardscape package, which is exactly why their method statements are written in a hurry. The consultant, however, reviews them against ADQCC Part 1 Roads, Section 7.5, line by line. A kerb method statement that states the values and the inspection gates of that section is usually approved first time; one that says “as per specification” usually is not.
The specification basis
For roads and hardscape under Abu Dhabi Municipality jurisdiction, the governing document is the ADQCC Standard Construction Specifications, Part 1 Roads (second edition), Section 7.5 for kerbs, with Chapter 4 for the concrete in the blinding and haunching. Cite the section in the references and in the methodology rather than test-method codes: the specification already incorporates them. If the project has a particular specification or approved shop drawings that set a different value (a 20 mm mortar bed instead of the default 25 mm, for example), state the project value and say where it comes from.
The installation sequence
Write the activity as one continuous sequence of steps. Consultants scrutinise sub-headings such as “Setting out”, “Polythene” and “Blinding” clause by clause, and they add length without adding control. The sequence that satisfies Section 7.5 runs as follows:
- Receiving inspection. Every delivery is checked and units are rejected for length variation over ±6 mm, alignment variation over ±3 mm, air holes of 3 mm or more, cracks over 75 mm, surface checking within five days of manufacture, or missing plant markings.
- Start condition. Kerb works start only after the base build-up layer is completed and approved.
- Set-out. The surveyor marks line, level and set-out from the approved shop drawings.
- Polythene and blinding. 1000-gauge polythene, then Class C20 blinding to the thickness on the approved detail.
- Bedding. Kerbs bedded on Class M6 mortar (ADQCC default 25 mm, or the drawing thickness) with the anchor grooves fully filled and the bed washed clean first.
- Joints. Not more than 4 mm, filled with Class M1 mortar containing one-fifth hydrated lime and finished with a grooving tool to a groove not deeper than 3 mm.
- Cuts and ends. Cut pieces not shorter than 200 mm, curved or sawn units below 3 m radius, and run ends sloped to ground level and turned 30° away from the road.
- Expansion joints. 10 mm filler at 9 m (or as the drawings show) through kerb, bed, backing and gutter.
- Inspection before haunching. Line and level inspected and approved through a work inspection request before any concrete is placed against the kerb; adjoining tops true within 1.5 mm.
- Haunching and backing. Continuous C20 backing; no pavement layer placed against the kerb until the backing is complete, backfilled and approved.
- Curing. Base, haunching and mortared joints cured and protected for seven days; improperly cured concrete is rejected and removed.
ADQCC requires two coats of water repellent on exposed kerb faces unless the kerbs are painted, but on most projects it sits in the main contractor’s scope. Check your subcontract before you write it into your method statement: once it is there, you own it. Where kerbs are painted, say alkyd or acrylic kerb paint and make the surface preparation an inspection step.
Acceptance criteria in one table
| Check | Criterion | Action on failure |
|---|---|---|
| Units on delivery | Length ±6 mm, alignment ±3 mm, air holes <3 mm, cracks ≤75 mm | Reject units |
| Kerb setting | Adjoining tops within 1.5 mm; joints ≤4 mm; M6 bed with grooves filled | Re-set before haunching |
| Backing and joints | Continuous C20 backing approved before pavement; 10 mm expansion joints at 9 m; M1 + 1/5 lime joints grooved ≤3 mm | No pavement until released |
| Curing | 7 days protected curing of base, backing and joints | Remove improperly cured concrete |
Inspection points the ITP must carry
The method statement describes the inspection steps; the inspection and test plan carries the hold and witness designations. For kerbs, the consultant expects at least: receiving inspection, blinding, the pre-haunching inspection (a hold point), backing complete before pavement (a hold point), surface preparation before painting where kerbs are painted, and final alignment. Never write “hold point” in the method statement itself: say “inspected and approved through a WIR” and leave the classification to the ITP.
Risk assessment controls that are specific to kerbs
Generic controls such as “manual handling precautions” draw comments. Write what the crew actually does: kerb units of 40 to 80 kg placed by vacuum lifter or kerb clamp or by two persons; wet cutting or extraction for silica dust; rubber gloves, long sleeves and goggles for wet concrete with eyewash at the front; the work area barricaded from plant and traffic. Cite ADOSH SF 4.0 Codes of Practice by their current numbers: CoP 14.0 Manual Handling and Ergonomics, CoP 35.0 Portable Power Tools, CoP 1.0 Hazardous Materials and CoP 44.0 Traffic Management and Logistics. Our ADOSH Code of Practice list shows which numbers are commonly mis-cited.
Comments to pre-empt
- “Coordination meeting required before start.” Write a preparatory meeting with the Engineer, notified at least two working days ahead, into the pre-work.
- “MEP clearance before excavation.” State that MEP clearance is obtained and approved by all disciplines before each work front.
- “Material approval and MIR.” Kerbs are installed only from approved material, accepted through a material inspection request on delivery.
- “Blinding thickness not stated.” Give the figure from the approved detail, not “as per drawing”.
Questions
ADQCC sets 25 mm as the default for the Class M6 bed. Many approved shop drawings show 20 mm. Use the approved drawing value and say so in the method statement, so the consultant can see where the figure comes from.
They can share one hardscape method statement where the consultant accepts combined submissions, but each must be its own activity with its own heading, ITP section and checklist. Never merge two activities under one heading.
Yes. Line and level must be accepted before concrete is placed against the kerb, because nothing can be corrected afterwards. Put it in the ITP as a hold point and in the method statement as an inspection step.
Jumbat Studio drafts the kerb method statement together with its ITP, risk assessment, inspection checklist and QA/QC register, in the format your client mandates, with every value taken from the current specification.
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