SNBVI contributes to the Envelope Quality Working Group

In accordance with the announcements of the Ministers for the Ecological Transition and Housing, the reinforcement of the building envelope must prevail because "the best energy is that which one does not spend". To achieve this, RE2020 intends to reduce the carbon impact of the construction of buildings and give priority to energy sobriety.

In order to promote the buildings that will anticipate the stages of RE2020 as well as the taking into account of new criteria in the foreshadowing of the buildings of tomorrow, the State wished to implement a Label jointly with the RE2020. It is not easy to position oneself on the architecture and content of a label accompanying the RE2002 when the legal texts of the regulations have not yet been published. However, the GTQE wishes to recall the points of vigilance to be taken into account in the development of the Label so that it can be a sign of support for innovation, for the exemplarity of actors and above all synonymous with a quality envelope. . The Envelope Quality Working Group, led by the Fibers-Energivie Pole, is committed to three main points to be taken into account in the development of an ambitious label:

1) A reinforced BBio

As part of the development of RE2020, the last government arbitrations adopted - without unanimity - by the CSCEE in April 2021 on the Bbio indicator reduced the energy performance requirements of small collectives and individual houses without providing compensation for large buildings. It is therefore imperative to raise the ambitions within the framework of the Label.

As such, the Envelope Quality Working Group supports a general strengthening of the Bbio indicator to RT2012-40%.

An ambitious Bbio indicator benefits the reinforcement of the envelope if and only if the singular points of the envelope whose thermal bridges are systematically treated by maintaining the guardrails. Article 31 of the RE2020 Requirements decree, relating to the treatment of thermal bridges, reveals a lack of ambition, even though the technical solutions have greatly evolved during the period of application of RT2012 and are now compatible. with all the construction methods at an optimized price.

The Envelope Quality Working Group supports the establishment of a Psi L9 value strictly lower than 0,4 W / ml- ° K within the framework of the Label.

In addition, in its current wording, article 31 presents imprecisions concerning the concept of “winter conditions” which could adversely affect the integrity of the building envelope and the health of the occupants. Indeed, depending on the assumption of outside and inside temperatures considered in certain climatic zones, this article could result in the non-treatment of thermal bridges in buildings and lead to less efficient construction solutions than RT2012. As such, the Envelope Quality Working Group recommends within the framework of the label an outside reference air temperature of -7 ° C, and an inside air temperature of + 20 ° C, the only way to ensure consistency of requirements.

2) A method for monitoring the quality of the studies upon completion

CEREMA (Center for Studies and Expertise on Risks, the Environment, Mobility and Planning) published in April 2021 the results of a study entitled "Demonstrator buildings with low energy consumption - Operational lessons 2012-2019 evaluations". This study presents national experience feedback relating to 166 low-consumption buildings. The main lesson put forward is that the expected design performance is not achieved in operation.

The study notes the following teaching on opaque walls: “Opaque walls: Control singular points, in particular thermal bridges to limit losses. Optimizing the implementation of insulation and airtightness ”

CEREMA highlights that the only solution is to think about performance at all stages and to integrate the concept of "overall cost".

The GTQE agrees with this position and has been promoting the implementation of a quality monitoring method such as commissioning for several years.

Extract from the GTQE White Paper - 2018: “Commissioning simply sets a framework in order to identify the causes of possible errors and make actions consistent […]. To be effective, commissioning must be integrated right from the award of contracts ”.

Extract from the GTQE Press Release - November 2020: "The commissioning of a building can be understood as a global quality approach which aims to guarantee the conformity of the performance of the building with the contractual documents".

THE GTQE recommends the implementation of energy performance monitoring through a mandatory commissioning procedure within the framework of the label. If this proposal appeared too ambitious, commissioning would be made mandatory at a minimum for the following types of buildings: early childhood, nursing homes, health, education. It also recommends updating the thermal bridging database libraries from current configurations and construction methods.

3) Control of the application of RE2020

The GTQE also supports independent monitoring of the application of RE2020 so that the regulations are truly effective and that no means can escape them. This method must be precisely defined, linked to quality monitoring (commissioning) and adopted for all projects subject to RE2020.

The GTQE recommends setting up a method for monitoring the application of RE2020, whether it be in declarative calculations or in actual performance by the town planning departments of local authorities.

While the French state was recently condemned for its climate inaction, the RE2020 Label must be ambitious and technically flawless. It should be remembered that buildings constructed from 2020 will represent 30% of the French real estate stock in 2050. Consequently, without strict and reinforced requirements, they will not be able to meet the ambitions of the National Low Carbon Strategy and it will be impossible to get out of the spiral of expensive home renovations.