Foamglas cellular glass insulation chosen for the construction of the roof of the Aquatic and Crossing Center in Saint-Denis (93)

Unique in the world, the roof of the Aquatic Center in Saint-Denis has a light wooden structure, including catenes with a span of 90 meters, with a surface area exceeding 10.000 m2, with slopes of up to 38% at the high points.

This roof supports nearly 2.255 photovoltaic modules intended to produce 805 kWp. Additional difficulty: the interior atmosphere is that of a building with very high humidity.

Overview of roofing and roles of FOAMGLAS cellular glass insulation

The roof of the Aquatic Center in Saint-Denis is characterized by ambitious architecture focused on sustainable design with low environmental impact. It houses a large pool hall offering the public 2.500 net seats, expandable up to 5.000 seats with a simple adaptation system. Its primary structure, 100% made of wood, is made up of catenes with a section of 50 x 20 cm displaying a concave shape in order to reduce the volume of air to be heated in the pool hall.

Its secondary structure (composed of battens placed on a batten) is also made of wood. Acoustic insulation is positioned between the battens. The steel trays, the supporting elements of the roof, are fixed on the battens. Above the steel trays is placed an adhesive vapor barrier for practical reasons. The FOAMGLAS® cellular glass thermal insulation is hot-glued, then the seals, made up of a bituminous membrane and a synthetic membrane, are heat-welded, each in full adhesion. At the high points of the roof, the slope reaches 38%. It is on this lightweight roof that 2.255 photovoltaic modules are integrated.

The crucial difficulty, unprecedented until now, was to design the fixing of the non-watertight photovoltaic modules on a solar roof characterized by strong inclinations. This roof was developed following a rigorous process including a Technical Experimentation Notice ( ATEX) of the CSTB, registered by Bouygues Bâtiment Ile-de-France, and has also been the subject of numerous laboratory tests. The entire design required the contribution of experts from various disciplines such as structure, sealing, fluids, thermal, aeraulics, acoustics, etc.

All of the design work was rewarded with the Construction and Development Prize as part of the Engineering Grand Prize awarded by Syntec in 2021. The second great reward was the good elevation of this remarkable work in compliance with the planned schedule.

Role of FOAMGLAS cellular glass insulation and its fixing plates

The function of FOAMGLAS® is to ensure thermal insulation of the construction roof using an ecological material recognized for its durability and its contribution to a circular economy. But the couple FOAMGLAS® + PC® SP 150 x 150 pads is much more…

FOAMGLAS® is made up of small glass bubbles that are sealed against each other. Made from recycled glass (60%), they form a very rigid and waterproof insulating foam. The insulating plates are glued to their support and to each other, forming a waterproof insulating and vapor barrier layer throughout. The rigidity and resistance to compression without settling of FOAMGLAS® make it possible to integrate notched plates, which are themselves fixing supports. This is what made it possible to manage the creep constraints with regard to the significant slopes of the structure.

Main qualities of FOAMGLAS cellular glass contributing to the successful completion of this work

Essential point: a thermal guarantee. It is the only thermal insulation guaranteed for 10 years by its manufacturer on site. This thermal guarantee is essential. It avoids any risk of the appearance of humidity and deterioration of the structure due to condensation phenomena, which can appear after several years following the loss of part of the efficiency. thermal insulation (see diagram below).

FOAMGLAS® ages while retaining all its thermal properties (analysis carried out by the BET of Munich FIW on several European construction sites over 40 years old). It is vapor-tight throughout and its plates are glued together over their entire thickness. FOAMGLAS® guarantees an absence of condensation on the roof for the entire life of the building.

Thanks to its rigidity, FOAMGLAS® presents itself as the most resistant insulation against settling under compressive stress. This quality is essential for solar roofs, where technical access may be necessary, thus exposing the waterproofing to mechanical constraints linked to pedestrian movements.

Unrivaled security against the risk of infiltration. The waterproof FOAMGLAS® cellular glass plates are glued directly to the adhesive vapor barrier and the plates are glued to each other and to the emergences. The Paradiène SR4 waterproofing and the Evalon® V membrane are fully heat-welded, without any semi-independence. The whole thing is compact and watertight as well as vapor tight throughout.

Essential point: the PC® SP 150/150 toothed fixing plates in Z 350 steel. Used for more than 20 years in France and patented by Pittsburgh Corning France, these 15 x 15 cm plates are equipped with 2 notched wings of 3 cm . By being inserted during the construction phase in the FOAMGLAS® insulating layer, they form a fixing surface without passing through the insulating layer, thus eliminating as many points of weakness for the work.

This device is validated for fixing, for example, metal roofing or slate roofing, and all types of waterproof facings. But here, the photovoltaic modules are not waterproof, and the slopes are higher than their usual implementation. It was therefore necessary to design a specific waterproof fixing device to receive the solar modules, in order to respond to the risks of being torn away in the wind and of creep in the area of the steeply sloped parts of the roof.

The company Dome Solar, specialized in the integration of solar devices on roofs, won the final choice of the integration system. The entire device was the subject of the CSTB ATEX submitted by Bouygues Bâtiment Ile-de-France, after numerous laboratory tests were carried out to check wind resistance, creep, aeraulics and water flow of such a design.

Aquatic Center and Crossing in Saint-Denis

The Greater Paris Metropolis is the contracting authority for the Aquatic Center, located in the heart of the Plaine Saulnier ZAC in the immediate vicinity of the Stade de France, the construction of which is being carried out by the group led by Bouygues Bâtiment Ile-de-France .

Designed by the architectural agencies VenhoevenCS and Ateliers 2/3/4/, the construction of the Aquatic Center in Saint-Denis is being carried out by Bouygues Bâtiment Ile-de-France, representative of the group. The Récréa company, an expert serving communities in the management and operation of aquatic and leisure centers in France, is responsible for operating the site, as part of a public service delegation, while Dalkia, as a player in the energy and digital transformation, ensures the technical maintenance of the building.