Quality Assurance in Construction

Quality Assurance in Construction - Quality assurance in construction encompasses all systematic measures designed to ensure that construction work, materials, and processes comply with agreed-upon standards, codes, and contractual requirements. It ranges from planning through on-site inspections during construction to final acceptance and protects the client from defects, consequential damages, and cost overruns.

Quality Assurance Tools

The most important tools are: On-site quality control (BQÜ) by an independent expert who inspects the workmanship during critical construction phases (foundation, waterproofing, roof truss, window installation). Material testing through test certificates and CE marking of the installed materials. Photographic documentation of all concealed work (reinforcement, pipe installation, waterproofing) before it is covered up. Pressure testing of heating and water pipes in accordance with DIN 1988. Blower door test to measure airtightness after completion of the building envelope. And the formal building inspection as the final quality control before handover.

Construction-Accompanying Quality Monitoring (BQÜ)

BQÜ conducted by an independent expert is the most effective measure for preventing construction defects. The expert typically conducts 5-8 site inspections during the construction phase and documents deviations from plans and standards. Studies by the Institute for Construction Research show that, on average, 28 defects are identified during acceptance for new buildings without BQÜ-compared to only 8 defects for buildings with BQÜ. The cost of a BQÜ is approximately 3,000-6,000 euros for a single-family home and is almost always recouped through avoided defect remediation costs.

Quality Assurance and Warranty Management

Another important aspect of quality assurance is active warranty management after acceptance. Within the five-year warranty period (§ 634a BGB), building owners should systematically check for hidden defects and report them in a timely manner. Especially shortly before the warranty period expires-that is, after about four years-a professional inspection by an expert is advisable to document any remaining defects and assert claims within the deadline. It is often at this point that defects come to light that did not manifest themselves in the first few years: moisture in the basement after a particularly wet winter, cracks forming after settlement, or material fatigue in waterproofing.

Practical Tip for Property Owners in Nuremberg

We recommend that property owners in the Nuremberg metropolitan area commission quality monitoring throughout the construction process for every new construction and major renovation project-regardless of whether you are building with a general contractor or through individual subcontracting. In Nuremberg, TÜV Süd, DEKRA, and numerous independent building experts offer BQÜ packages. Monitoring is particularly critical for basement construction in areas at risk of groundwater contamination (e.g., in Katzwang or along the Pegnitz River), for attic conversions in older buildings, and for energy-efficient renovations, where faulty insulation or airtightness layers can lead to mold damage.

For building owners who wish to utilize KfW subsidies under the Federal Program for Efficient Buildings (BEG), the involvement of an energy efficiency expert is mandatory anyway-this expert can also simultaneously take on tasks related to quality monitoring during construction, thereby saving costs compared to a completely separate contract.

Quality Assurance During Final Inspection

The final inspection is the most legally significant moment in the construction process: Upon acceptance, the burden of proof shifts from the contractor to the client. Before acceptance, the contractor must prove that their work is free of defects; after acceptance, the client must prove that a defect was already present at the time of acceptance. It is therefore crucial not to declare acceptance lightly and to document all identifiable defects in writing in the acceptance report.

During the formal acceptance, the client and the contractor inspect the building together. All defects are documented and given a deadline for rectification. Only once all defects have been rectified is the withheld final payment (usually 5% of the contract sum) paid out. Those who consult an expert during the acceptance inspection have a significantly better chance of discovering hidden defects that laypeople cannot see-such as missing fire-resistant seals, leaky gutter connections, or inadequate reinforcement cover in the foundation.

Digital Documentation as a Quality Tool

Modern construction supervision increasingly uses digital tools to improve quality assurance. Building experts create their inspection reports using photo documentation apps that automatically geotag and timestamp images. Defect management software allows defects to be linked to responsibility, deadlines, and status, and transmitted to the contractor as a list. This creates transparency for building owners: they can see at any time which defects are outstanding, have been rectified, or are in dispute. Those who forego paper records and document digitally have a complete chain of evidence in the event of a dispute.

Frequently Asked Questions

When should a building inspector be consulted?

Ideally, before signing a contract with the contractor: The expert can review the construction contract and specifications for gaps and risks. During the construction phase, they should be on-site at least for the following milestones: excavation/foundation, basement waterproofing, completion of the shell, roof covering, window installation, and before the screed is laid. Their presence is particularly valuable during the final inspection, as they can identify hidden defects that laypeople might overlook.

Who pays for quality assurance?

The costs of the quality assurance are borne by the builder-they are not included in the construction contract and are agreed upon separately with the expert. For a single-family home in Nuremberg, the costs are approximately 3,000-6,000 euros (depending on the number of inspections and the scope of work). For KfW-subsidized energy-efficient homes, the involvement of an energy efficiency expert is mandatory anyway-this expert can sometimes also take on the BQÜ tasks. The costs are tax-deductible as production costs.

What to do if defects are found?

Defects discovered during the construction phase must be reported to the contractor in writing and with a deadline for rectification. Important: Document every defect with photos, the date, and a description. At the final inspection, all outstanding defects should be recorded in the inspection report, and a retention for defects (typically 5% of the contract amount) should be agreed upon, which is only paid out after all defects have been rectified. In the case of serious defects, acceptance may be refused.

Does quality assurance also apply to renovations?

Yes, and in renovations it is often even more important than in new construction. Renovations of older buildings frequently bring surprises: hazardous substances (asbestos, PAHs), unexpected structural defects, or structural peculiarities that were not visible during the initial survey. An expert who monitors the renovation work can identify when contractors encounter unforeseen situations and can initiate adjustments to the scope of work early on-before they result in cost increases or damage.

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