Thermal Insulation Technical Proposal: EWI, IWI and Thermal Bridge Treatment in Public Contracts
Thermal insulation contracts are at the heart of public building energy transition. With the tertiary decree, Climate and Resilience Act, and thermal sieve reduction targets, tender volumes are exploding. To stand out, the proposal must go beyond simply describing insulation material: calculated thermal performance, systematic thermal bridge treatment, energy certificate compliance, and coordination with affected trades.
Specific challenges of thermal insulation contracts
The buyer evaluates your offer on precise technical criteria: the proposed thermal resistance R (which must meet RE2020 or existing RT regulatory thresholds), thermal bridge treatment (which can represent up to 40% of heat losses if ignored), compatibility with other trades (windows, ventilation, heating), and compliance with CEE (Energy Savings Certificates) requirements if the contract involves an aid scheme.
Key point: RGE qualification is often a sine qua non. Without it, the contracting authority cannot benefit from CEE or MaPrimeRénov', making your offer economically unviable against RGE competitors.
Technical elements expected in the proposal
A convincing thermal insulation proposal relies on quantified, verifiable data.
Thermal performance and insulation choice
Detail for each treated zone: proposed insulation (type, thickness, thermal resistance R, ACERMI certification), the resulting thermal transmittance coefficient U of the wall+insulation assembly, and compliance with applicable regulatory requirements. For EWI, specify the complete system: ETICS (render on insulation) or ventilated cladding, with CSTB technical assessment.
Thermal bridges and airtightness
Thermal bridge treatment differentiates technical bids. Detail each critical junction with drawings: window reveals and lintels, window sills, wall corners, floor/facade junction, parapets. Propose a Blower Door infiltrometry test to validate airtightness performance after works.
EWI systems: which system for which building
The buyer appreciates a proposal that justifies system choice. ETICS is suitable for flat facades without particular constraints, offering good cost/performance ratio. Ventilated cladding suits exposed facades and tall buildings, allowing thicker bio-sourced insulation. A comparative table of systems with cost, performance, and implementation constraints demonstrates genuine expertise.
Disqualifying errors in insulation contracts
Not being RGE qualified — This is a deal-breaker for any contract involving CEE or public aids.
Ignoring thermal bridges — Insulation without critical junction treatment loses up to 40% of its effectiveness.
Insulation without ACERMI — Proposing insulation without ACERMI certification prevents guaranteed thermal performance claims.
Forgetting ventilation — Insulating without addressing mechanical ventilation creates condensation and mould risks.
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