Regional branch of SMABTP in Rennes, France
By awarding the project with the French HQE sustainability certificate, the most important insurance partner of the French construction industry sets an example for energy efficiency.
Simple and efficient construction
The concrete pillar and beam structure is clad with a curtain-type, rear-ventilated façade with a wooden substructure. The walls are supplied as airtight and watertight prefabricated components with built-in windows and doors to keep construction time to a minimum.
Pre-manufacturing parts off-site is also a valuable way of optimising the quality of the workmanship. This, of course, is because if you are carrying out work at great heights and in dry conditions, it is easier to do so inside a factory.
Since the plan is to use cellulose insulation, this insulation will be injected on site, to prevent any settling when the components are transported in particular.
Because the structure will be certified as a passive building, it is essential that it be airtight. The N50 value must not exceed the threshold value of 0.6 1/h, which means an air exchange rate about 5 times lower than the reference value according to French regulations RT2012 and now RE2020.
The way in which the building architecture is planned and manufactured to include a façade with a wooden substructure make it significantly easier to achieve this goal. Nevertheless, a few individual points had to be addressed in detail.
In his role as the project manager handling the project at timber construction company BRIERO, Gael Jaslet contacted SIGA and asked them to organise a comprehensive training course for all project stakeholders, whether based in the factory or on the construction site. This gave the company’s experienced employees the opportunity to bring their knowledge up-to-date, and new employees received comprehensive training.
A prototype was available for the training session, making it possible for participants to focus on the complex elements.
The main issue for discussion ended up being the connections around the windows and doors, as well as the numerous connections on the concrete.
To avoid taking any risks, Majvest 700 façade membrane was used on the exterior of the building, because of its excellent UV resistance. This will protect the façade from wind and weather for a few months, as the special metal cladding cannot be installed in the factory.