Construction Products Regulation: CE Marking for Structural Sealants

What the Construction Products Regulation Is and Why It Exists

The CPR replaced the earlier Construction Products Directive 89/106/EEC to close a gap that had frustrated the EU single market for decades: national testing and approval regimes for construction products meant a sealant certified in one member state often had to be re-tested and re-approved to be sold in another. The Regulation applies directly across every member state without national transposition, and it fixes a single mechanism — the Declaration of Performance backed by CE marking — through which a manufacturer states, once, how a product performs against the essential characteristics that matter for its intended construction use.

The CPR does not set minimum performance thresholds itself. Instead, it obliges the manufacturer to test the product against the essential characteristics defined in the relevant harmonised technical specification and to declare the result honestly, whatever that result is. It is then left to national building regulations, procurement specifications, and the specifying architect or engineer to decide what level of each characteristic a given project requires. For a structural sealant, this means the regulation exists to guarantee that the movement class, adhesion performance, and durability printed on the Declaration of Performance are the actual, independently verified figures — not marketing claims — so a specifier anywhere in the EU can compare products on a common, trustworthy basis.

Scope: Who the CPR Applies To and Which Sealants Are Covered

The CPR applies to any construction product placed on the EU market where a harmonised technical specification exists and covers that product's intended use. For sealants, the key harmonised standard is EN 15651, published in parts that separately address facade sealants, glazing sealants, sanitary sealants, and sealants for pedestrian walkways. A sealant manufacturer, importer, or authorised representative bringing a covered product into the EU carries the CE marking obligation regardless of where the product is physically manufactured, and the obligation attaches to the specific intended use claimed, not to the chemistry of the sealant in the abstract.

A sealant sold exclusively for a use outside these four categories, or one for which no harmonised standard yet exists, does not carry a mandatory CE marking obligation under the CPR, though many manufacturers still commission the same testing voluntarily because architects and public procurement specifications increasingly expect a Declaration of Performance as a baseline qualification document. Structural glazing sealants deserve particular attention: where a sealant is used as the primary structural attachment between glass and frame rather than purely as a weather seal, the essential characteristics that must be declared, and in some cases the applicable AVCP system, differ from a purely weatherproofing joint. Our guide to silicone sealant types and grades sets out the chemistry distinctions between weatherproofing and structural glazing formulations that feed into this scope question.

Key Requirements: Declaration of Performance and CE Marking

Once a sealant falls inside the scope of EN 15651, three obligations follow in sequence: the essential characteristics relevant to the intended use must be tested and classified, a Declaration of Performance must be drawn up stating those results, and the CE mark must be affixed with reference to that Declaration. Skipping any one of the three — testing without declaring, declaring without marking, or marking without current testing — breaks compliance even if the underlying product performs well.

Essential Characteristics and EN ISO 11600 Classification

EN 15651 references EN ISO 11600 for the movement-capability and modulus classification that forms the technical core of the Declaration of Performance. Under EN ISO 11600, a sealant is classified by a movement class figure — such as 12.5, 20, or 25 — expressing the maximum percentage of joint width the sealant can accommodate through repeated extension and compression without adhesive or cohesive failure, combined with a category letter set (F or G for the general class, and LM or HM for low or high modulus) describing the force the cured sealant exerts on the substrate at that movement. A structural glazing joint exposed to significant thermal cycling needs a materially different classification than a static sanitary joint, so the declared class must match the actual joint design movement calculated for the building detail in question.

Assessment and Verification of Constancy of Performance (AVCP)

The CPR assigns each essential characteristic an AVCP system that fixes how conformity is assessed and by whom. Most characteristics for sealants under EN 15651 fall under AVCP System 3, meaning an accredited, notified testing laboratory carries out initial type testing to determine the product's performance, while the manufacturer itself operates factory production control and self-declares performance without ongoing notified body surveillance of production. Some structural and fire-related characteristics can carry a stricter system requiring notified body certification of the factory production control system itself, so the applicable AVCP system must be confirmed characteristic by characteristic rather than assumed for the product as a whole.

Testing and Documentation Requirements

The evidence base behind a compliant CE mark has to satisfy two different audiences at once: a market surveillance authority checking the Declaration of Performance is genuine, and a specifying engineer relying on the declared movement class to design a real joint. Because of this dual purpose, sealant manufacturers must hold both the formal conformity documents and the underlying test data, not just a signed declaration.

• Initial type testing report — the accredited laboratory's test report determining movement capability class, elastic recovery, tensile properties, and adhesion/cohesion performance under EN ISO 11600 and the relevant EN 15651 part.
• Declaration of Performance (DoP) — the formal document identifying the product, its AVCP system, the harmonised standard reference, and the declared level for every essential characteristic, issued before the CE mark is affixed.
• Factory production control (FPC) records — documented evidence that ongoing production is monitored against the same parameters verified during initial type testing, including raw material checks and batch testing logs.
• CE marking label content — the CE symbol itself accompanied by the notified body number where applicable, the last two digits of the year the marking was first affixed, manufacturer identification, and a reference to the DoP.
• Safety Data Sheet — reflecting the CLP classification of the cured and uncured sealant, maintained consistently with any hazard-related essential characteristics declared.
• Retest triggers documentation — a record of any formulation, raw material, or manufacturing process change that could affect a declared characteristic, and confirmation of whether it required new initial type testing.

A Declaration of Performance is only as reliable as the initial type test it rests on, so it expires in practice the moment a formulation changes materially. Treat every reformulation as a trigger to review, not an administrative afterthought.

Step-by-Step Compliance Pathway to CE Marking

Reaching a compliant CE mark for a structural sealant follows a defined sequence, and the order matters: testing must exist before the Declaration of Performance is written, and the Declaration must exist before the CE mark is affixed. The steps below map that sequence for a sealant manufacturer supplying the EU market.

1. Identify the applicable EN 15651 part and confirm scope. Match the sealant's intended use — facade, glazing, sanitary, or pedestrian walkway — to the correct part of the harmonised standard, and confirm the product genuinely falls within its scope.
2. Commission initial type testing with an accredited laboratory. Submit representative production samples for EN ISO 11600 movement classification and the other essential characteristics required by the relevant EN 15651 part.
3. Determine the applicable AVCP system for each characteristic. Confirm whether notified body involvement is required beyond initial type testing, based on the essential characteristics being declared and the standard's assigned system.
4. Draft the Declaration of Performance. Compile the tested results into the DoP format required by CPR Annex III, stating declared levels honestly, including any characteristics for which "No Performance Determined" is the accurate answer.
5. Establish factory production control. Implement and document the raw material checks, in-process controls, and batch release testing needed to demonstrate that ongoing production matches the tested product type.
6. Affix the CE mark and publish the DoP. Apply the CE mark to the product, packaging, or accompanying documents per CPR Article 9, referencing the DoP, and make the DoP available in the language required by each member state of sale.
7. Monitor for retest triggers. Track formulation, raw material, and process changes on a controlled basis, and repeat initial type testing whenever a change could plausibly affect a declared essential characteristic.

Realistic Timeline and Cost Expectations

CE marking a new structural sealant is a multi-month technical programme, not a form-filling exercise, because the classification testing itself takes time to run correctly and cannot be meaningfully compressed. Understanding the real cost drivers helps a manufacturer budget the programme accurately rather than being surprised by the testing timeline midway through a product launch.

Initial type testing for EN ISO 11600 movement classification typically requires curing and conditioning cycles measured in weeks before cyclic movement testing can even begin, followed by the test sequence itself and laboratory reporting time — a realistic total of two to four months for a first-time submission, longer if any result requires reformulation and retesting. The main cost categories are accredited laboratory fees for initial type testing, internal technical time to prepare samples and interpret results, DoP drafting and multilingual translation for each market of sale, and — where a stricter AVCP system applies — notified body fees for factory production control certification and its ongoing surveillance visits.

Reformulation after a failed or marginal classification result is the timeline risk that catches manufacturers off guard: a sealant that narrowly misses its target movement class or elastic recovery threshold must be reformulated and the full initial type testing cycle repeated, effectively resetting the clock. Building in a testing buffer before a firm launch date, and validating a formulation against the target classification internally before committing to accredited laboratory testing, meaningfully de-risks the programme.

Common Mistakes Manufacturers Make — and How to Avoid Them

Most CPR non-compliance in the sealant sector is not deliberate — it stems from treating CE marking as a one-time certificate rather than a live obligation tied to the exact tested formulation and use. The patterns below recur across market surveillance findings and specification disputes, and each is preventable with a disciplined process.

• Reformulating without retesting. Changing a raw material, catalyst level, or filler loading can shift movement capability or adhesion performance enough to invalidate the existing Declaration of Performance, even though the CE mark stays unchanged on the packaging.
• Confusing weatherproofing classification with structural glazing requirements. A sealant classified and declared for a facade weather-seal joint is not automatically qualified for a structural glazing attachment role, which can carry different essential characteristics and AVCP treatment.
• Issuing a DoP before testing is complete. Drafting the Declaration of Performance ahead of receiving final, accredited test results and then not correcting it if results differ is a direct breach of Article 4's requirement that declared performance reflect actual, verified test outcomes.
• Applying the CE mark without a corresponding DoP reference. The CE mark is only meaningful attached to a specific Declaration of Performance; using it without one, or with a DoP that has lapsed due to formulation change, is treated as non-compliant marking.
• Overlooking member state language requirements for the DoP. Distributing a product into a new member state without providing the Declaration of Performance in that state's required language can block procurement acceptance even when the underlying technical compliance is sound.
• Assuming a foreign national approval substitutes for CE marking. A sealant approved under a non-EU national scheme, or under an old pre-CPR national mark, still needs full CPR conformity to be lawfully placed on the EU market.

For background on the chemistry decisions that shape which classification a sealant can realistically achieve, the Global Formulation guide to MS polymer hybrid sealants covers movement and modulus trade-offs across chemistries, while the adhesives and sealants formulation guide sets out the broader additive and cure-system landscape. Official CPR guidance is maintained by the European Commission and EUR-Lex at Regulation (EU) No 305/2011, and the harmonised classification standard is published by ISO at iso.org/standard/69818.