Documented examples of existing situations regarding quality of works. QUALICHeCK Report: "Towards improved quality of the works"

Rapport, 2016

This report, written in the context of the IEE project QUALICHeCK, summarises critical situations on the construction site that are liable to put the careful execution and thus the high quality of works at risk. It gives an introduction into the importance of high quality constructions and their realisation on the building site in connection with the trend towards high performance buildings such as the nearly zero-energy buildings required by the Energy Performance of Buildings Directive (Recast) for 2019 respectively 2021.

First, a matrix of possible critical situations encountered on the construction site was developed, ranging from general issues like missing specifications, insufficient knowledge and training of the workers, etc. to more specific problems with certain building envelope components and material and to building service systems and their components. The critical situations are opposed to four technology focus areas in the QUALICHeCK project (transmission characteristics, ventilation and air tightness, sustainable summer comfort technologies, and renewables in multi-energy systems). Reasons for problems with the quality of works have been structured and comprise poor specifications of projects, standards or regulations, lack of competences, critical economic conditions and lack of control.

All in all, 28 studies and other documented experiences that show the probability, the reasons and the impact of incorrect realisation processes at the building sites have been collected in the participating countries of the project and are inserted into the matrix. They are also included in a tabular overview and presented in greater detail, including references. For several countries the results of the BUILD UP Skills projects, that analysed the need for competent workforce, could be included. Several documented studies deal with specific technologies such as heat pumps, solar thermal systems, PV systems, ventilation systems or insulation material and technologies such as loose fill material or external thermal insulation composite systems (ETICS). Other studies are based on building inspections to guarantee a high quality of works and give an overall impression of mistakes occurring on construction sites. Based on the gathered documented experiences there seems to be considerable knowledge of the situation in some of the focus areas like building envelope airtightness and ductwork airtightness (especially in Northern and Middle European countries), but less knowledge of issues like sustainable summer comfort and renewables in multi-energy systems.

Additionally, a first collection of best practice solutions to avoid low quality realisations is presented in the report. They will build the basis for further work in the project. So far, the collection includes several guidelines for improving the quality of works, some training and certification schemes for installers and other workers that are partly driven by the industry involved and some control schemes realised by experts from third parties. The control schemes are mostly voluntary. If they are associated with financial schemes they often present a mandatory check for receiving the financial support.

This document is the final public version of a draft report published in March 2013 that was intended for discussion with stakeholders, both bilaterally and during workshops. This earlier collection of studies and experiences has been extended based on further work within the project and feedback from stakeholders.