Analysis and expertise at the service of the envelope of the building
A Global Approach for a Sustainable Envelope
FX SA is a recognized specialist of the building envelope. Our activity is primarily based on the analysis of defects, the preparation of technical reports, and the execution of expert assessments on facades, roofs, terraces, and balconies. We bring together a team of experts covering all technical aspects of these structures in order to identify pathologies, analyze their causes, and propose suitable solutions.
Expert assessment missions aim in particular to diagnose defects, non-conformities, or deterioration that may affect a building and to determine their origin.
As a specialized AMO (Owner’s Representative) in the building envelope, we support building owners and project teams upstream of operations, particularly in the context of architectural competitions or preliminary studies, in order to integrate the technical requirements of the envelope from the design phase and ensure lasting performance of the structures.
The building envelope cannot be thought of as a simple sum of components: it must be approached as a coherent system, where technical rigor, understanding of materials, and mastery of interfaces are essential to guarantee performance, durability, and reliability.
An inadequate or poorly designed envelope can lead to tangible consequences: waterproofing or thermal performance defects cause energy losses that can represent up to 65% of the overall heat loss of a building, particularly in non-renovated constructions, which directly impacts consumption and operating costs.
In this context, the architect is responsible for the design, the shape of the building, the legibility of the project, and the aesthetic integration into its environment: they create what “looks beautiful,” while reconciling the functional, regulatory, and contextual constraints of the site. Their role is essential to ensure a quality spatial and aesthetic proposal while meeting the building owner’s intentions.
Alongside them, the engineer is responsible for the technical functioning of the envelope and its compliance with standards: they translate architectural intentions into buildable and high-performing solutions, verify the thermal, mechanical, and hygrometric performance of materials and assemblies, and ensure that the whole meets regulatory, energy, and durability requirements.
Without this technical approach, invisible defects can quickly become major problems: it is estimated that approximately 50% of studied envelope failures are linked to moisture problems due to design or integration errors, often causing structural deterioration or degraded performance.
Industry statistics also show that a large majority of commercial buildings have air leaks or infiltrations, reducing energy efficiency by up to 25–35% and generating heating and air conditioning surcharges.
Our role is to provide clear, independent, analysis-based expertise, at the service of demanding and complex projects. We analyze and diagnose the performance of components and systems, identify critical interactions between elements, and formulate robust recommendations to ensure that the architectural vision is realized in compliance with technical performance, current standards, and durability requirements, while minimizing the risks of cost overruns, pathologies, and premature failures.
Our Areas of Expertise
A Structured Expertise at the Service of the Building Envelope
FX SA covers all technical aspects related to the building envelope. Our expertise is structured around clearly identified areas, covering materials, construction systems, structure, building physics, overall performance, and technical expertise.
Knowledge of Materials and Their Behavior
FX SA analyzes building envelope materials by evaluating their mechanical, thermal, and hygrometric properties, as well as their behavior over time. This expertise is based on testing, field inspections, and a detailed understanding of aging phenomena.
Construction Systems and Facade Typologies
We work on all facade systems, including load-bearing facades, plastered facades, wood or wood-metal facades, and curtain walls. Particular attention is paid to connections and construction details, which are essential to performance and durability.
Structural Calculation and Material Strength
FX SA ensures the dimensioning and structural verification of envelope elements. Our analyses incorporate mechanical constraints, deformation phenomena, and material compatibility.
Building Physics and Thermal Transfers
Mastery of thermal transfers is at the heart of our approach. FX SA analyzes insulation, thermal inertia, air and water tightness, as well as hygrometry management and condensation risks. We also place great importance on solar protection.
Overall Performance and Durability
Our interventions aim for lasting overall building performance. FX SA evaluates energy and hygrothermal comfort, integrates climatic constraints, and supports projects in compliance with environmental standards and certifications.
Expertises, Technical Assistance, Inspection and Monitoring
FX SA carries out technical expert assessments and assistance missions at all project phases. These interventions include diagnostics, implementation inspections, on-site verifications, and independent technical opinions.
Expertises and Technical Assistance
An Operational Expertise, at the Heart of Projects
FX SA works on complex projects, providing independent technical expertise and support at all project phases. Our missions aim to analyze defects, understand their causes, and propose suitable solutions, while securing technical choices in both design and execution.
Our Projects
From Design to Technical Expertise
FX SA covers all technical aspects related to the building envelope. Our expertise is structured around clearly identified areas, covering materials, construction systems, structure, building physics, overall performance, and technical expertise.
From Research
to Implementation
Research, Development, and Protection of Innovative Technical Solutions
Innovation is an integral part of FX SA’s approach. Our engineers closely follow the evolution of technologies, materials, and methods applied to the building envelope in order to anticipate regulatory and technical developments in the sector.
This dynamic is supported by continuous scientific monitoring, participation in specialized conferences, and the development of innovative solutions in collaboration with Universities of Applied Sciences.
In this context, FX SA has developed and filed several patents, notably in the fields of all-glass facades FELIWALL and design profiles. Beyond the patents, numerous systems have been tested, certified, and implemented in concrete projects, following a logic of custom solutions, technically mastered and adapted to the specific requirements of each project.
Research, Development, and Protection of Innovative Technical Solutions
Innovation is an integral part of FX SA’s approach. Our engineers closely follow the evolution of technologies, materials, and methods applied to the building envelope in order to anticipate regulatory and technical developments in the sector.
This dynamic is supported by continuous scientific monitoring, participation in specialized conferences, and the development of innovative solutions in collaboration with Universities of Applied Sciences.
In this context, FX SA has developed and filed several patents, notably in the fields of all-glass facades FELIWALL and design profiles. Beyond the patents, numerous systems have been tested, certified, and implemented in concrete projects, following a logic of custom solutions, technically mastered and adapted to the specific requirements of each project.
Laurent Felix
After Félix Constructions SA and BIFF SA, Laurent Félix now develops FXSA, an EXPERT engineering firm founded on technical expertise and experience gained in the field of the building envelope: all types of facades, windows, and roofing.
“The architect is responsible for beauty”: designing the form, volumes, and aesthetic expression of the building. Their role is to propose a vision that “looks beautiful,” while respecting the major constraints of the program and urban planning rules. Alongside them, “the engineer is responsible for performance” and compliance with standards: they ensure that the design is viable from a thermal, mechanical, and hygrothermal perspective, that the targeted performances are achieved, and that the proposed solutions meet regulatory and sustainability requirements.
Laurent Felix
After Félix Constructions SA and BIFF SA, Laurent Félix now develops FXSA, an EXPERT engineering firm founded on technical expertise and experience gained in the field of the building envelope: all types of facades, windows, and roofing.
“The architect is responsible for beauty”: designing the form, volumes, and aesthetic expression of the building. Their role is to propose a vision that “looks beautiful,” while respecting the major constraints of the program and urban planning rules. Alongside them, “the engineer is responsible for performance” and compliance with standards: they ensure that the design is viable from a thermal, mechanical, and hygrothermal perspective, that the targeted performances are achieved, and that the proposed solutions meet regulatory and sustainability requirements.
