New Road Construction
QA inspection checklist

Formation & Earthworks

1. 1.

   Formation level correct per design

   Record: Level (m AOD)
   What to look forFormation surveyed by GPS rover or total station against the design surface model. Levels checked at sufficient density (typical 10-20 m grid). Tolerance recorded; out-of-tolerance areas re-graded.
   Acceptable whenPer SHW Series 600 / DMRB CD 225: formation level tolerance ±25 mm of design. Slope to drain transverse falls per design (typically 2.5%). No soft or hollow spots > 50 mm deep.
   StandardSHW Series 600 — Earthworks. SHW Clause 612. DMRB CD 225 / 226 — Pavement design and construction.
   Common defectsFormation high — sub-base must be re-gradedFormation low — extra fill required, cost over-runNo survey records — formation level unverifiedSurface uneven — pumping under construction trafficCrossfall reversed in places
2. 2.

   CBR / plate bearing test results acceptable

   Record: CBR (%)
   What to look forIn-situ CBR or plate bearing tests at frequencies in spec (typically 1 per 250 m² or 1 per 100 m carriageway). Results compared with design CBR. Areas below threshold proof-rolled and improved.
   Acceptable whenPer DMRB CD 225 / SHW Clause 612: design CBR for sub-formation typically ≥ 5% for capping; ≥ 15% for direct sub-base. Plate bearing K-value per design.
   StandardBS 1377-9:1990 — In-situ tests. SHW Clause 612 / 638. DMRB CD 225.
   Common defectsCBR < design — capping or sub-base does not performTest density too low — coverage gapsTests biased away from soft areasNo engineer review of resultsSample size not statistically representative
3. 3.

   Geotextile membrane installed where specified
   What to look forGeotextile separation / filter / reinforcement layer per design. Manufacturer code matches spec. Lapped per design (300-500 mm). Continuous, no tears. Edges anchored before fill placement. Reinforcement geogrids tied per supplier instructions.
   Acceptable whenPer BS EN 13249 (roads) / 13251 (earthworks): geotextile to declared performance class. Lap ≥ 300 mm; ≥ 500 mm on weak ground. Reinforcement geogrid laps connected per supplier (Tensar, Maccaferri).
   StandardBS EN 13249:2016. BS EN 13251:2016. DMRB CD 225 / SHW 600.
   Common defectsLap too short — separation function lostGeotextile torn during fill placementWrong grade (non-woven instead of woven for reinforcement)Edges flapped up by wind before fillGeogrid laps not connected — no reinforcement transfer
4. 4.

   Capping layer material and depth correct

   Record: Depth (mm)
   What to look forCapping layer (Class 6F2 / 6F3 / 6F4 / 6F5 well-graded granular fill or stabilised material) per design. Delivery tickets retained. Depth verified at trial pits / probing. Compaction by method spec or end-product.
   Acceptable whenPer SHW Clause 614 / DMRB CD 225: capping per design CBR uplift, typically 150-600 mm of Class 6F per design. Material per Table 6/1. Compaction per Table 6/4.
   StandardSHW Clause 614. SHW Table 6/1, 6/4. DMRB CD 225.
   Common defectsCapping depth less than design — sub-base fails to spread loadWrong class (6F2 instead of 6F4) — not as designedCompaction insufficient — capping ruts under loaded plantCapping not protected from rain — saturated, failsNo depth records
5. 5.

   Formation dry and stable — no soft spots
   What to look forWalked / proof-rolled formation. No springiness, pumping, or rutting > 25 mm under loaded tipper. No standing water. Soft spots remediated by excavation and replacement, geotextile / geogrid uplift, or lime stabilisation.
   Acceptable whenPer SHW Clause 612.4: formation accepted by visual / proof-roll. No movement under loaded plant. Engineer signs off.
   StandardSHW Clause 612. DMRB CD 225.
   Common defectsSoft spot covered by capping — settlement after constructionPumping ignored — water trappedTrafficked formation by site plant — surface destroyedNo engineer sign-offRemediation method (excavation depth / replacement) not recorded

Sub-Base

1. 6.

   Sub-base material to specification (Type 1 / Type 2)
   What to look forSub-base material per design — Type 1 or Type 2 granular per SHW Clause 803 / 804. Source declaration / certificates of conformity. Visual confirms grading. PSV and other quality measures per design.
   Acceptable whenPer SHW Clauses 803 / 804: Type 1 well-graded 0/63 mm, plasticity index zero; Type 2 0/40 mm, PI ≤ 6. CE/UKCA per BS EN 13242. Frost-susceptibility per BS 812-124.
   StandardSHW Clauses 803 / 804. BS EN 13242. BS 812-124 (frost susceptibility).
   Common defectsType 2 supplied where Type 1 specifiedExcess fines — pumpingFrost-susceptible material not detectedNo conformity certificatesRecycled aggregate not tested per SHW Clause 710
2. 7.

   Laid and compacted in correct layer thickness

   Record: Depth (mm)
   What to look forSub-base placed in lifts ≤ 225 mm compacted (per material and plant). Number of passes per Table 6/4. Surface trimmed to design profile. Depth verified at trial holes.
   Acceptable whenPer SHW Clause 803: lift thickness per Table 6/4; passes per Table 6/4. Total compacted depth per design ±10 mm.
   StandardSHW Clause 803. SHW Table 6/4.
   Common defectsLift > 225 mm — only top compactsNumber of passes not countedDepth measured before compactionNo edge compaction (edges loose)Plant too light for material
3. 8.

   Compaction test results acceptable
   What to look forIn-situ density / CBR tests at frequency in spec. Compared against design value. End-product or method spec recorded. Engineer reviews results.
   Acceptable whenPer SHW Clause 803.7: end-product 95% MDD typical, or method spec (passes per layer per plant). CBR ≥ 30% on compacted Type 1 sub-base. Frequency 1 per 500 m² typical.
   StandardBS 1377-9:1990. SHW Clauses 803, 612. DMRB CD 225.
   Common defectsDensity < 95% MDD — surface course will rut earlyTest frequency below specTests biased to easy locationsNuclear gauge uncalibrated for materialNo record of test results
4. 9.

   Levels and crossfall correct

   Record: Crossfall (1 in ?)
   What to look forSub-base levels surveyed and compared with design. Crossfall measured with digital level across road. Vertical curves smooth. Edges trimmed to alignment of kerbs / channels.
   Acceptable whenPer SHW Clause 702: surface tolerance ±15 mm of design (sub-base). Crossfall ±0.5%. Vertical alignment smooth — no kinks.
   StandardSHW Clause 702. DMRB CD 116 / 226.
   Common defectsCrossfall reversed — water ponds across roadSub-base high — surface course laid thinnerSub-base low — extra surfacing depth requiredVertical kink at construction jointEdges off alignment — kerbs do not fit

Base Course & Binder

1. 10.

   Base course material to specification
   What to look forBase course (binder course) material per design — typically AC 32 dense base, AC 20 dense binder course, or HRA. Mix design and CE/UKCA mark on delivery ticket. Binder grade matched. PSV / aggregate per design.
   Acceptable whenPer SHW Series 900 Clauses 911-913 / DMRB CD 226: mix designation, binder grade, and aggregate per design. CE/UKCA per BS EN 13108.
   StandardSHW Series 900. BS EN 13108-1:2016 (AC). DMRB CD 226.
   Common defectsWrong binder grade (40/60 vs 50/70) — temperature-sensitive performanceWrong aggregate PSV — non-compliant for road categoryMix not certified — non-compliantBinder course substituted with weaker mix
2. 11.

   Laid at correct temperature

   Record: Temp (°C)
   What to look forMix delivered above minimum temperature. Temperature checked at lorry, paver hopper, and behind paver. Cessation criteria observed in cool/wet weather. Insulating sheets used.
   Acceptable whenPer SHW Table 9/14: AC binder course minimum laydown ≥ 110-120°C (varies by binder). Cessation below; rolling complete before mat ≤ 80°C.
   StandardSHW Series 900 Table 9/14. SHW Clause 902.
   Common defectsTemperature below 110°C — compaction fails, voidsMat cooled before rolling — no further densityNo temperature recordMix carted too farInsulating sheets not used in cool weather
3. 12.

   Thickness correct

   Record: Thickness (mm)
   What to look forCompacted thickness measured at trial holes and cores. Layer brought up uniformly. No thin patches.
   Acceptable whenPer SHW Series 900 / DMRB CD 226: design thickness ±10 mm; cores at 1 per 1000 m². Total flexible pavement to design.
   StandardSHW Series 900. DMRB CD 226.
   Common defectsLayer thinner than spec — premature ruttingThickness measured loose, not compactedHidden thin spots — not picked upNo core recordTotal pavement under-built
4. 13.

   Joints offset from sub-base joints
   What to look forLongitudinal joints in surface and binder course offset from sub-base joints by minimum 300 mm. Transverse joints staggered through layers. No coincident joints throughout pavement depth.
   Acceptable whenPer SHW Clauses 902 / 919: longitudinal joint offset ≥ 300 mm between successive layers. Transverse joints offset to avoid weak section. Joints rolled and finished.
   StandardSHW Series 900 Clauses 902, 919.
   Common defectsCoincident joints — vertical line of weakness through pavementJoints all at lane line — wheel-track failureJoints not rolled — bumpy rideCold joints between paving sessions — bond fails
5. 14.

   Tack coat applied between layers
   What to look forTack coat (cationic emulsion C40B4 or PMB) applied on every prepared base before next layer. Even spread, no puddles or misses. Allowed to break before next lay.
   Acceptable whenPer SHW Clause 920: tack rate 0.2-0.4 L/m² residual binder. Coverage uniform. Allow break (typically 30 min) before paving.
   StandardSHW Clause 920.
   Common defectsNo tack between binder and surface — bond failsTack puddled — slip planeTack rate too lowPaver tracking through wet tack — emulsion entrainedNo tack on vertical joint face

Surface Course

1. 15.

   Surface course material matches specification
   What to look forSurface course type per design — SMA, AC10/AC14 dense surface, HRA with chippings, or thin surface system. Mix designation and aggregate PSV per design. CE/UKCA per BS EN 13108.
   Acceptable whenPer SHW Series 900 / DMRB CD 226: surface course matches design — material, binder grade, aggregate PSV. CE/UKCA per BS EN 13108-1/-4/-5.
   StandardSHW Series 900. BS EN 13108. DMRB CD 226.
   Common defectsAC10 substituted for SMA — surface texture different, durability lowerPSV too low for road categoryWrong binder gradeNo certification documentationRecycled content above spec limit
2. 16.

   Temperature at laying correct

   Record: Temp (°C)
   What to look forMix above minimum laydown temperature at all stages. Compaction within window. No cold material laid. Temperature records logged.
   Acceptable whenPer SHW Table 9/14: surface course laydown ≥ 130°C (50/70 binder). Cessation below. Rolling complete before mat falls below 80°C.
   StandardSHW Series 900 Table 9/14.
   Common defectsTemperature low — voids high, ravelsRolling left too lateNo temperature recordsMix carted from distant plant — cooled in transit
3. 17.

   Finished thickness correct

   Record: Thickness (mm)
   What to look forCompacted thickness measured by depth gauge / cores. Uniform across area. No feathered edges.
   Acceptable whenPer SHW Series 900: typical surface 30-40 mm; ±5 mm of design. Cores at 1 per 1000 m².
   StandardSHW Series 900. DMRB CD 226.
   Common defectsThinner than spec — durability halvedFeathered edges — ravels in 1 winterHidden thin spotsNo core record
4. 18.

   Surface regularity within tolerance

   Record: Deviation (mm)
   What to look for3 m straightedge / rolling straightedge across surface. No rocking. No birdbaths. Long-wave undulation absent. Joints flush.
   Acceptable whenPer SHW Clause 921 / DMRB CD 226: ±3 mm in 3 m for high-speed road carriageway. Rolling straightedge for long-wave on adopted highway.
   StandardSHW Clause 921. DMRB CD 226. BS 1230.
   Common defectsRocks > 5 mm — non-compliantLong-wave from auger irregular feedStep at lane jointBirdbath at gully
5. 19.

   Joints straight, clean, and sealed
   What to look forLongitudinal joints between paving passes hot-vertical and tightly bonded. Transverse joints (day joints) cut back vertical. Joint tape or hot bitumen applied after compaction.
   Acceptable whenPer SHW Clauses 902 / 919 / 920: joint vertical, tack-painted, sealed after rolling with hot-applied joint sealant per BS EN 14188-1.
   StandardSHW Clauses 902, 919, 920. BS EN 14188-1.
   Common defectsCold joint — failure within 1 winterStep at jointNo joint sealantFanned edges, not verticalNo tack to vertical face
6. 20.

   Texture depth acceptable

   Record: Texture (mm)
   What to look forSand patch test or texture depth meter at sample points. Texture per design — typically ≥ 1.5 mm initially for high-speed roads. PSV verified by aggregate certificate. Skid resistance test (SCRIM) where required.
   Acceptable whenPer SHW Clause 921 / DMRB CS 230: texture depth ≥ 1.0 mm 30/50 percentile (HRA), ≥ 1.3 mm SMA, per design. SRV / SCRIM per CS 228.
   StandardSHW Clause 921. DMRB CS 230 / CS 228. BS EN 13036-1 (sand patch).
   Common defectsTexture < spec — skid resistance failPolished aggregate (low PSV) — texture deteriorates fastBleeding (fat-up) — texture lostNo texture record
7. 21.

   Core samples taken and recorded
   What to look forCores cut at agreed locations. Measured for thickness, layer integrity, and density. Lab tested for binder content and grading. Holes reinstated immediately.
   Acceptable whenPer SHW Clauses 929 / 930 / DMRB CD 226: PRD ≥ 93% (surface), ≥ 92% (binder); air voids 4-7% (surface). Binder content ±0.3% of design. Cores at 1 per 1000 m².
   StandardSHW Series 900. BS EN 12697-6 / -8 / -39.
   Common defectsPRD < 93% — premature failureAir voids > 8% — water entry, oxidationCores from easy locations onlyHoles reinstated coldNo record

Drainage

1. 22.

   Gullies installed at correct levels and spacing
   What to look forGully positions per design — at low points, before junctions, at maximum spacing for catchment. Tops set 5-10 mm below carriageway. Frame bedded firmly.
   Acceptable whenPer SHW Clause 511 / DMRB CD 526: gully spacing per design discharge calc — typically 30-50 m on motorway, closer at junctions. Frame Class D400 (carriageway).
   StandardSHW Clause 511. DMRB CD 526. Sewers for Adoption 7th Ed.
   Common defectsGully top proud — water bypassesSpacing too far — ponding betweenClass B125 cover in carriageway — collapsesGully chamber off line — drain run kinksFrame not bedded — rocks under traffic
2. 23.

   Kerb drainage channels clear
   What to look forKerb drainage / channel block runs continuous along kerb line, with falls towards gullies. Outlets to gully clean. No blockage from construction debris. Concrete bedding intact.
   Acceptable whenPer SHW Clause 1102 / Section 5: continuous channel with consistent fall to each gully outlet. No reverse falls. No standing water > 24 hours.
   StandardSHW Clauses 511, 1102. BS EN 1340. DMRB CD 526.
   Common defectsChannel block stepped — water cannot reach gullyConstruction debris in channelReverse fall sectionOutlet to gully not alignedConcrete bedding cracked
3. 24.

   Connection to outfall confirmed
   What to look forOutfall to existing drainage system, attenuation pond, or watercourse. Connection inspected and tested. Discharge consent in place if to watercourse. Flow proven from gully to outfall.
   Acceptable whenPer Sewers for Adoption / Environment Agency: connection to public sewer requires Section 106 / 104 agreement; to watercourse requires discharge consent. Flow test from upstream gullies to confirm.
   StandardSewers for Adoption 7th Ed. Water Industry Act 1991 Sections 104, 106. Environmental Permitting Regulations 2016.
   Common defectsNo agreement / consent — illegal dischargeConnection blocked at adoption testFlow does not reach outfall — kink in pipeWrong outfall connected (foul into surface water sewer)No flow test
4. 25.

   CCTV survey of new drainage completed
   What to look forCCTV survey of all new drainage by WRc-certified operator. Continuous footage with chainage. Any defects graded per MSCC5. Survey accepted by sewerage undertaker for adoption.
   Acceptable whenPer WRc MSCC5 / Sewers for Adoption: structural Grade 1 expected throughout new installation; service Grade 1-2 acceptable. Adoption inspector reviews and accepts.
   StandardWRc Manual of Sewer Condition Classification 5. Sewers for Adoption 7th Ed.
   Common defectsJoint displacement (J grade > 1) — joints not fully homeDebris in pipe — not jetted before surveySurvey not accepted by undertaker — adoption blockedOperator not WRc-certifiedNo record of report

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