Construction Quality Control

Quality Control System

Construction quality is a critical factor for the success of a development project. Poor construction leads to reputational losses, legal claims, warranty expenses, and a reduction in the value of the asset. The quality control system includes several levels.

Levels of Control

1. Employer's Representative / Clerk of Works

Employer's Agent — control carried out on behalf of the developer (client) regarding the quality of construction works.

Functions:

• Verification of compliance of works with design documentation and specifications
• Control over materials quality (certificates, laboratory tests, CE marking)
• Inspection of hidden works (foundations, reinforcement, waterproofing)
• Verification of volumes of completed works (verification of Interim Payment Applications)
• Maintenance of Site Diary and Progress Reports
• Participation in acceptance of structures (hold-point inspections)

2. Design Review / Design Supervision

Design supervision — control by the designer over the precise compliance of construction with design documentation.

• Conducted by Lead Designer / Architect
• Records deviations from the design (Non-Conformance Reports — NCR)
• Approves changes made during construction (Architect's Instructions)
• In UK: mandatory Design Review under CDM Regulations (Construction Design and Management)

3. Third Party Inspection / Building Control

Building Control (United Kingdom):

• Approved Inspectors or Local Authority Building Control
• Verifies compliance with Building Regulations
• Issues Completion Certificate

Dubai Municipality Inspection (UAE):

• Inspections at key stages (foundation, structure, MEP, finishing)
• Third Party Inspection Bodies (accredited by Dubai Municipality)
• Verifies compliance with Dubai Building Code
• Issues Completion Certificate

4. Laboratory Control and Testing

Laboratory testing of materials and structures:

• Concrete strength (cube tests, non-destructive testing)
• Quality of reinforcement (certificates, visual inspection, tensile tests)
• Survey control (survey checks, verticality)
• Soil testing (pile load tests)
• Fire resistance testing
• MEP commissioning and testing of engineering systems

Quality Standards

Eurocodes (EN 1990 — EN 1999):

• EN 1992 — design of concrete structures
• EN 1993 — design of steel structures
• EN 1994 — design of composite steel and concrete structures
• EN 1998 — seismic design

UAE:

• Dubai Building Code — based on International Building Code (IBC)
• Abu Dhabi International Building Code (ADIBC)
• ACI 318 — standard for concrete structures (widely used in UAE)

Sustainability Certification:

• LEED (Leadership in Energy and Environmental Design)
• BREEAM (Building Research Establishment Environmental Assessment Method)
• Estidama Pearl Rating System (Abu Dhabi)
• WELL Building Standard (health and wellbeing of users)

Typical Construction Defects

Structural defects:

• Cracks in load-bearing structures
• Deviations from design dimensions
• Poor-quality waterproofing (especially critical in UAE — high groundwater)
• Violation of reinforcement

Engineering defects (MEP):

• Pipe leaks
• Poor air-conditioning (critical in UAE — main climate system)
• Electrical issues
• Fire system defects

Finishing defects:

• Uneven walls and floors
• Defects in windows and façade glazing
• Poor-quality tiling (cracks, unevenness)
• Problems with doors and fittings

Snagging and Acceptance

During handover, the buyer conducts a snagging inspection — an apartment walkthrough to record defects. The developer must rectify justified defects (snag items).

What to pay attention to during acceptance:

• Apartment area (should correspond to SPA, permissible deviation usually 2–5%)
• Windows and glazing (operation, tightness, double glazing)
• Walls (evenness, absence of cracks)
• Floors (evenness, absence of voids under tiles/screed)
• Ceilings (evenness, absence of leaks)
• HVAC (air-conditioning — check operation, temperature)
• Electrical (operation of sockets, switches, smart home systems)
• Plumbing (operation of taps, absence of leaks, sewage)

Warranty Obligations

United Kingdom (NHBC Buildmark):

• 2 years — Builder Warranty Period (developer rectifies defects)
• 8 years — NHBC structural insurance (structural defects, total: 10 years)

UAE (DLD regulations):

• 1 year — Defects Liability Period (DLP) — developer rectifies all defects
• 10 years — structural warranty (structural elements)

Germany:

• 5 years — BGB warranty (or 4 years under VOB)
• Covers all defects, including structural and engineering

Digital Technologies for Quality Control

Modern technologies significantly enhance the efficiency of construction quality control, moving processes from “paper-based” to real time.

BIM integration: The BIM model is used as the “reference” for comparison with the constructed object. 3D scanners generate a point cloud of the actual building, which is automatically compared to the BIM model — deviations exceeding the tolerance are immediately recorded and sent to an NCR (Non-Conformance Report). This eliminates the human factor in detecting deviations.

Mobile QA/QC platforms:

• Autodesk Construction Cloud (ACC): digital checklists, inspections, NCR tracking, BIM integration — used on 99% of major projects in UK and increasingly in UAE
• Fieldwire: mobile application for field teams — tasks, snag lists, photo documentation with geolocation on the floor plan
• Dalux: BIM viewer for construction site workers — each worker sees their scope in the model

Drone inspections as QA tool: Drones with thermal cameras detect:

• Voids in façade insulation (cold bridges are visible on IR images)
• Roof leaks before final covering
• Waterproofing quality of underground structures

AI defect analysis: Startups (Doxel, Buildots) use computer vision for automatic defect detection on construction site videos. The system “learns” from thousands of images and flags violations independently — from incorrect reinforcement installation to poor welding quality. Accuracy — up to 85% of defects detected by an experienced Clerk of Works, with 10 times less labor input.

Practical Assignment

<details> <summary>Assignment: Apartment Handover Checklist</summary>

Compile a detailed checklist for snagging inspection of an apartment in a new development.

Sample answer:

Entrance door:

• Opens/closes without effort
• Locks function (smart lock / mechanical)
• Seal is intact
• Peephole / intercom in place

Windows and balcony doors:

• All sashes open/close
• Double glazing free of cracks and condensation
• Handles work
• Sills undamaged
• Reveals are even

Walls and ceilings:

• Evenness (check with 2 m straightedge)
• No cracks
• Paint/wallpaper free of defects
• Corners are even (90°)

Floors:

• Evenness (level)
• No voids under screed (tapping)
• Laminate/tiles free of defects
• Skirting installed correctly

Electrical:

• All sockets work (tester)
• Switches operate
• Meter installed
• Circuit breakers in panel

Plumbing:

• Water from all taps
• Sewage works (pour water)
• No leaks
• Heated towel rail works

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