Block paving quality control and documentation

Why does quality control matter?

The durability of a block pavement is not decided at the moment of laying – it is decided by whether every single layer was built with the right material, the right compaction and the right levels and falls. Quality control is therefore a continuous process that runs from the arrival of the materials to the handover of the finished pavement.

On public and urbanisation works, quality control is mandatory and documented – but it is advisable for private clients too: one compaction test and one material certificate can save the cost of a major repair a few years down the line.

1. Checking incoming materials

Concrete paving blocks (UNE-EN 1338)

Concrete pavers must meet the requirements of UNE-EN 1338. What to check:

• CE marking and declaration of performance (DoP): mandatory with every delivery under Regulation (EU) 305/2011; they certify the declared characteristics.
• Dimensions and thickness: deviation from the nominal size must not exceed the permitted tolerance; thickness must match the load category (6, 8, 10 or 12 cm).
• Colour and surface: uniformity within the batch, checking for damage and spalling.
• Abrasion resistance and weathering durability: stated in the declaration of performance; order the class matching the expected exposure (in the inland comarcas, with occasional light frosts, a higher durability class is advisable).
• Laying pattern: the format must match the design; for special units, check the proportions.

Crushed stone and sub-base materials

• Aggregate to UNE-EN 13242 – checking the fraction (0/32, 0/45, etc.).
• Grading: on the delivery note or with a laboratory report.
• Cleanliness: mud, clay and organic matter are not permitted; check visually as well.
• Moisture content: the optimum moisture range is needed at placing for proper compaction.

Kerb units (UNE-EN 1340)

• Dimensions, thickness, breaking strength.
• CE marking, declaration of performance.
• Checking for surface damage and cracks.

Bedding material

• 2/5 or 4/8 grit, clean, without a fine sandy fraction.
• Laboratory verification of the grading is recommended.

2. Checking the formation and the sub-base

Checking the formation level

After shaping the formation – before spreading the sub-base – check:

• Levels and falls: with a laser level or rotating laser, minimum 2% crossfall away from the building.
• Bearing capacity: with a plate load test (Ev2 modulus) or another recognised test method; the design value must be reached.
• Uniformity: no settlement, soft spots or areas contaminated with fines are permitted.
• Drainage: is any standing water left?

Sub-base – intermediate inspection before covering

An inspection record of covered-up work must be produced for every layer that will be hidden. On completion of the sub-base, check:

• Layer thickness: by core sample or probing; any deviation from the design thickness is documented.
• Compaction: degree of compaction referenced to the Proctor test, or a plate load test (Ev2 modulus).
• Grading: if there was a laboratory test, the report is attached.
• Levels and falls: the basis for the level check after the bedding layer.
• Kerb stability: hardening of the concrete bed, presence of the haunching, levels.

3. Checking the finished pavement

Surface regularity

• 4 m straightedge: on public works the permitted deviation is typically ≤ 10 mm; on private jobs, per the tolerance agreed with the client.
• Stepping between units: the height difference between adjacent blocks must not exceed the accepted threshold (stricter on accessible routes).
• Rocking blocks: every rocking unit must be relaid and its joint refilled.

Falls and drainage

• Measure the falls on the finished surface as well – do they match the design?
• Check for ponding in rain or with a hose test.
• Check the connection of channels and gullies.

Joints and jointing

• Is the joint width as designed (generally 3–5 mm)?
• Is the jointing material filled to full depth?
• Top up any empty or washed-out joint sections.
• With polymeric jointing material, re-inspect after the curing time has passed.

Kerbs

• Level retention, junction with the blocks.
• Stability – any rocking or displacement?
• Has the concrete haunching hardened?

Cuts and junctions

• Cut blocks should not be smaller than 1/3 of a unit (especially in trafficked zones).
• Does the area around utility covers sit evenly?
• Accuracy of junctions with building plinths and gates.

4. Documentation – what to keep, and how?

Documentation is not only mandatory (on public works) – it protects the interests of both the client and the contractor. If a dispute arises, documentation is the only objective evidence.

What to photograph

Phases that should always be recorded:

1. Formation level – after compaction, before covering.
2. Geotextile / geogrid – if present, condition as laid.
3. Sub-base – layers during spreading and after compaction.
4. Kerbs with their concrete bed – before covering.
5. Bedding layer – even spreading.
6. Block laying – during the work, with the pattern visible.
7. Jointing and compaction.
8. Finished pavement, channels, gullies, kerb junctions.
9. Junctions at utility covers.
10. Junctions with building plinths and gates.

5. Handover and warranty

The handover procedure

1. Site walk-through with the client: inspecting every area.
2. Recording snags and defects in the handover record – with a deadline and a responsible party.
3. Handing over the documentation: material certificates, test records, photographs.
4. Written warranty statement.
5. Signatures: by both parties.

Follow-up inspection

The joint material can still settle in the first weeks after laying. Recommended:

• Check the jointing after 2–4 weeks and top up if needed.
• After the first heavy autumn rains, a level check – look for wash-out or settlement.
• On busy areas, return within six months to a year and check the joint condition.