A rendered external wall insulation system is not declared with a single environmental product declaration. It takes two, and the producer of the render system declaration says so itself: its declaration has to be added to an insulation declaration to represent a complete system. On declarations actually registered with INIES the gap is stark. The 120 mm EPS board at R = 3.85 m².K/W of declaration no. 20250544058, verified on 23 July 2025, weighs 5.88 kg CO₂ eq per m² over a reference service life of fifty years. The render system covering it, declaration no. 205273752982021, weighs 32.1 over the same period. Optimising board thickness therefore works on a fifth of the problem.
What a life cycle assessment measures, and what it rests on
The two declarations that make up the system
An environmental declaration describes a product, not a completed element. On a rendered insulation system, the insulation board and the render system are two separate declarations, held by two different declarants, and both are needed to speak about the facade. The table below gives the header characteristics of each, the ones a consulting engineer checks before even looking at a result.
| Declaration | Reference standard | Functional unit | Climate change, whole life cycle |
|---|---|---|---|
| Sto-Panneau Isolant Top31, EPS 120 mm, R = 3.85 m².K/W, INIES no. 20250544058, verified 23/07/2025 | NF EN 15804+A2 and NF EN 15804+A2/CN | 1 m² of insulation board on a wall from the outside, 50-year reference service life, fixing accessories excluded | 5.88 kg CO₂ eq |
| Render system for external insulation without insulation, Groupement du Mur Manteau, INIES no. 205273752982021, published September 2021 | NF EN 15804+A1 and NF EN 15804/CN | 1 m² of rendered external insulation facade over EPS, mineral wool, phenolic foam or wood fibre, 50-year reference service life | 32.1 kg CO₂ eq |
Two immediate lessons. The first is the ratio of one to five and a half between the insulation and the render that protects it, the opposite of the reflex that argues about EPS thickness. The second is the difference in standard between the two declarations, which forbids adding them without care: how a declaration and its scope are read is covered in environmental product declarations.
The withdrawal date, the line to check first
A declaration is valid for five years, stated in its header. The render system one, published in September 2021, carries an end of validity date in September 2026. On top of that comes a programme decision: any declaration verified after 1 November 2022 must comply with NF EN 15804+A2, and the steering committee of the INIES programme set out on 6 January 2026, at the request of the French housing directorate, the archiving timetable for the remaining +A1 declarations, from 1 January 2026 for those verified in 2020, 1 April 2026 for those granted an extension, and 1 July 2026 for those verified in 2021 and 2022. Before carrying a declaration into a note, open the database and check it is still there.
The functional unit, which decides what is comparable
The functional unit of the insulation board is one square metre of board fitted to a wall from the outside, over fifty years, fixing accessories excluded. The render system one is one square metre of facade covered, protected and decorated, over fifty years. Both hold the square metre and the period, so geometrically they add up. But the explicit exclusion of fixing accessories on the insulation side means that fixings, base rails and corner beads are only covered by the second declaration, which makes the addition compulsory rather than optional.
Where the carbon of a rendered EPS system actually sits
The module breakdown, read off the declaration
The headline result says nothing until the modules are opened. Here is the breakdown of the climate change indicator of the render system declaration, per square metre of facade and over fifty years.
| Module | Item | kg CO₂ eq/m² | Share of the life cycle |
|---|---|---|---|
| A1 | Raw materials | 11.9 | 37 % |
| A2 | Upstream transport | 3.70 | 12 % |
| A3 | Manufacturing | 1.33 | 4 % |
| A4 | Transport to site | 4.77 | 15 % |
| A5 | Installation | 0.678 | 2 % |
| B2 | Maintenance over the reference service life | 7.83 | 24 % |
| C1 to C4 | End of life | 1.89 | 6 % |
| Total | Life cycle | 32.1 | 100 % |
Transport to site weighs more than manufacturing itself, and close to four times the installation. That is a lever you can reach, unlike the composition of the mortars: shortening the supply chain can be quantified, and proved by the delivery notes.
Maintenance, the item nobody prices
The 7.83 kg CO₂ eq of module B2 do not come from a vague assumption. The declaration sets out its scenario: after fifteen years a semi-thick coating is added to the system, and after thirty years the refurbishment is done with a finishing render in half of the cases and with a semi-thick coating in the other half. In other words, a quarter of the render system's footprint comes from two maintenance visits that nobody mentions to the client at the point of sale. Saying it before the sale changes the conversation, because it turns an insulation quote into a commitment over time.
End of life, a landfill scenario
The end of life scenario the declaration retains is explicit and a long way from the recycling narrative: the system is taken down with the wall, only the aluminium base rails are recycled, the rest is collected then hauled thirty kilometres to a consolidation centre and sent to landfill after a further hundred kilometres. No recycling credit is taken for the EPS, because the board leaves the wall contaminated by adhesive and render. That is the reality to bring to a meeting, rather than a promise of a recovery route that is not in the declaration.
What you can write, and what you cannot
Adding across two standards is not clean
The render system declaration explicitly asks to be added to a compatible insulation declaration. The difficulty is that the system declaration is drawn up to NF EN 15804+A1 while the board declaration falls under NF EN 15804+A2: the two standards do not define the same indicators and the second changed the content of several of them. Two courses hold. Either you find two declarations on the same standard, which is the only clean route since the +A1 declarations were archived. Or you present the two results separately, each with its standard and its registration number, with no total. A mixed total is spotted at once and discredits the whole note.
What set-out actually changes
Careful set-out cuts board offcuts, and therefore the A1 to A3 share of the insulation declaration, which is 5.21 kg CO₂ eq per square metre. Five points of offcuts avoided on that item represent 0.26 kg CO₂ eq per square metre, whereas a shorter supply chain acting on module A4 of the render system plays on 4.77. The trade-off is arithmetic, not ideological. That is obviously no reason to skip set-out: its first purpose is to treat the junctions properly, a subject covered in junctions in external wall insulation.
The documents to attach to a simplified assessment
A defensible note holds in four documents. Without them the exercise is not open to challenge and it is worth nothing against a consulting engineer.
- The declarations as PDFs, with registration number, verification date and end of validity date visible.
- The take-off of net facade areas, openings deducted, from the same survey as the quote.
- The quantities of accessories actually fitted, fixings, base rails, beads, rather than theoretical quantities.
- The transport assumptions used, distance and mode, with the source of the distance.
Answering a request from the client side
What can be required in retrofit, and what cannot
The environmental performance requirement carried by the French RE2020 applies to new build. On the retrofit of an existing building, no general regulatory duty requires a life cycle assessment. A request from the client side therefore arises from the contract, from a public procurement or from a voluntary certification, and it is handled as such: you answer what is asked, with verifiable sources, and you commit to nothing beyond. Saying that a requirement does not exist is stronger than producing a figure you cannot defend.
Stating a gap between options without over-reading it
When two options are compared, the gap only means something if both sets of declarations share the standard, the reference service life and the scope of the modules. On a thin render against a rainscreen cladding comparison, the second solution changes the declarations from top to bottom and adds a framework, so the gap cannot be derived from a rule of three on thicknesses. The environmental data of timber cladding and its durability trade-offs are covered in external insulation with timber cladding.
The lines that come out of the quote
The take-off behind an assessment note is the same as the one behind the quote, and there is no reason to do it twice. Net facade areas, openings deducted, running metres of junctions, accessory quantities: those figures come out of the survey once and feed both documents, provided facade areas and openings are measured to the square metre. A discrepancy between the take-off on the quote and the one in the assessment note is the first thing a checker looks for, and the easiest to avoid.
