La Maison du tourisme de Troyes: a historic heritage protected from fire by Promat

Originally the home of a wealthy merchant, this sixteenth-century half-timbered building (rebuilt identically following the fire that devastated the city in 1524 on a dense plot of medieval base), has today hui vocation of reception and information for the public and the tourists.

In order to be able to fulfill this mission, an extension in communicating joint ownership, in a more contemporary architectural continuity, scrupulously respecting the regulations of the protected historical perimeter of the protected sector of the city of Troyes, has been added. This extension and rehabilitation of the 90th century building make it possible, on the one hand, to accommodate all of the city's tourism-related services and, on the other hand, to deal with the problems of access to PRMs encountered between the original construction and its high ground floor, placed 712 cm above the public space, and the low ground floor of the new building. The whole, henceforth accessible to all, represents XNUMX m² spread over five levels, cellars and attics included. The three main levels are served by an elevator, one of the cage walls of which, flush with the center of the extension's facade, is hidden behind an aesthetic cladding in gray Aube poplar, pierced by three bays.

This is very important work for a site on which original and efficient solutions have been adopted in order to give this rehabilitation-extension the essential qualities to make it an ERP with an environmental and sustainable profile. Indeed, thanks to drastic energy management, acoustic and hygrometric comfort, accessibility for all, indoor air quality, high functionality of use and the implementation of regulatory security against fire, the Maison du tourisme de Troyes has all the qualities to welcome tourists.

Claire Perron, heritage architect for the city of Troyes and responsible for the project, declares: “Our work had to be carried out with historical respect for the transmission of timber frame construction methods, that they reveal the historical evolution. by highlighting preserved characteristic elements, making them a model that can be transposed to future restoration operations in the city of Troyes. But also that they are proof that a renovation of a XNUMXth century wooden building can display an energy level equivalent to the performance of the BBC. Finally, they required the BBC-Effinergie Rénovation qualification and the characteristics relating to the status of an ERP ”.

For this rehabilitation, for which the City of Troyes was both client and contractor, the greatest precautions were taken in order to respect as faithfully as possible the soul of the XNUMXth century construction model. A new filling of the timber frames, on the cob principle, was necessary while adding insulation and breathing properties; reuse, restore, replace joists, beams and lumber; reconstitute a roof in terracotta tiles; respect the components of the molding and enhance them; replace the disappeared corbels ... It was also necessary to find a sum of structural complements, as for the stone and brick fireplaces, to calibrate and position the openings to harmoniously punctuate the facades, to bring a contemporary design to the composition of the new facades wood of the extension, in particular the double windows, find and apply plasters based on local sands and natural “breathable” earth-based paints, favor finally, and as in the past, materials of local and regional origin ...

Two emblematic characteristics illustrate this exceptional achievement:

• Use hemp concrete with a lime binder (similar to the cob principle), validated by a scientific committee, to treat the building envelope, the filling of the timber frames and insulate the under-roof. This material provides thermal insulation and allows optimal “breathing” of the building.
   
• Provide this exceptional historic building with all the necessary passive safety against the risks of fire and face the very specific requirements of this site for which, beyond protection against fire, the choice of materials also makes it possible to guarantee the sound insulation, resistance to impacts and punctures, lightness.

Promat has deployed various suitable solutions: incombustible and rot-proof silico-limestone sheets for certain 60-minute fire-resistant compartments and a sprayed fibrous mixture classified A1, based on slag wool and hydraulic and inorganic binders.

One of the major constraints was not to weigh down the construction, the original foundations being preserved. The lightness of Promat products met this requirement. The other was to be particularly dependent on the existing structures preserved, in particular by giving an essential flexibility to the fixings of the Promat plates so that they absorb, without risk, the movements of the wood.

It is on the underside of the old joists and floors of the first and second floors that 100 mm PROMATECT®-15 ceilings were fixed to a metal framework, creating a 35 cm plenum, and on the ground floor. paved on new wooden joists of suitable section. Part of the circulation of the main entrance as well as the elevator shaft were treated with MASTERIMPACT® -RH sheets (12 mm thick) for their impact resistance qualities. Finally, the basement rooms, restored or new, and the technical rooms have received the projection of PROMASPRAY® F250 on the underside.

This ambitious and very successful rehabilitation project was able to combine the new performance of an environmental profile with the upgrading of an exceptional built heritage, offering accessibility, comfort and safety to all its users.

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