Second-Generation Eurocodes: What to Change in Your Specifications by March 2028

What is the timeline for the second-generation Eurocodes in the UK?

First- and second-generation Eurocodes coexist from 2023 until 30 March 2028, when BSI withdraws the first-generation adoptions and their National Annexes. BSI's target is to publish all UK National Annexes by 30 September 2027. Until then, the first generation remains the applicable set unless a project says otherwise.

The dates below come from the IStructE Eurocodes FAQs (published 19 October 2026), which draw on BSI and CEN milestones, and from the JRC Eurocodes site. They are the dates a practice needs to plan to.

Three points follow from the timeline. First, availability is not the same as usability in the UK. Each second-generation Eurocode must be used with its UK National Annex, and the Annexes are not all due until 30 September 2027. Second, BSI now classes the first generation as "current, superseded" rather than "withdrawn, superseded". IStructE reminds designers that until 30 March 2028 the first-generation documents should be considered the applicable standards for buildings and civil engineering works constructed in the UK, unless the relevant authority or the project specification says otherwise. Third, IStructE does not encourage mixing generations in one design. The phrase "unless otherwise specified" is why the specification matters: the choice of generation is a project decision, and it belongs in the document.

The IStructE FAQs also make clear that in practice adoption depends on how the new Eurocodes are referenced in contracts and in the Approved Documents supporting the Building Regulations. Check the current Approved Document references to the Eurocodes for any change.

What changes in EN 1990, EN 1992, EN 1993 and EN 1997?

EN 1990 absorbs the basis of geotechnical design and keeps consequence classes. EN 1992-1-1 absorbs bridges and liquid-retaining structures and introduces new shear models and Exposure Resistance Classes. EN 1993 extends steel grades to S700, adds new parts and renumbers clauses. EN 1997 is reorganised into three parts.

The changes below are summarised from the JRC Eurocodes site, the Concrete Centre, New Steel Construction and published commentary on EN 1990 and EN 1997. They are headline changes only. The standards themselves, with their UK National Foreword and National Annex, govern.

EN 1990 and EN 1997

Geotechnical design now sits under a combined basis of design: the 2023 edition of EN 1990 covers the basis and theory previously in EN 1997-1. The new EN 1997 is organised in three parts: general rules, ground properties, and geotechnical structures. For a specification, the practical effect is that a piling, retaining wall or ground improvement clause that cites EN 1997-1 and EN 1997-2 by clause number will no longer map to the new structure. SPERW 3rd Edition (2016) pre-dates the second generation, so check the interface between its requirements and the design standard on a project that will use the new EN 1997.

EN 1992, concrete

The Concrete Centre notes that EN 1992-1-1 and -1-2 were published in 2004 and that the update is a significant revision with a much wider scope. For specification writers the most relevant items are the move of bridges and liquid-retaining structures into the main part, the new shear and punching models, and the Exposure Resistance Classes. The UK does not currently use the EC2 durability method, which is subject to National Annex, and refers to BS 8500. The Concrete Centre expects the BS 8500 approach to continue initially, with a longer-term aim that novel, potentially lower-carbon concretes can be given an ERC through accelerated testing. The execution standard, BS EN 13670, sits alongside it and the NSCS 5th Edition complies with it. Check the current status of BS EN 13670 alongside the design codes.

EN 1993, steel

New Steel Construction summarises the most general changes: a revised table of contents, so designers must relearn where clauses are; scope extended to S700; the new parts 1-13 and 1-14; and revised rules for lateral-torsional buckling, semi-compact sections, fatigue and joints. A specification that cites clause numbers in EN 1993 will break. The more subtle dependency is the execution side. First-generation practice selects Execution Class through the design standard and its National Annex, and the NSSS and BS EN 1090-2 are written around it. Check with the BCSA and BSI for any revision of BS EN 1090-2 and the NSSS to match.

What does the change do to a specification?

It affects every place a specification names a design standard, an edition, a clause number, a steel grade, an exposure rule or a load value. Most of the effort is finding those references, not rewriting them.

Seven kinds of entry are likely to need attention. Few of them will need new thinking. All of them need locating.

• ✓Design basis clause: standard titles and editions for EN 1990 to EN 1999, and the statement of which generation applies.
• ✓Normative reference lists: the list of referenced standards, which in many masters has grown by accretion.
• ✓Clause-level cross-references: any citation of a clause or table number within a Eurocode, which will not map across generations.
• ✓Material entries: steel grades, sub-grades, concrete exposure and cover rules and recycled aggregate or cement requirements.
• ✓Dependencies on national specifications: the NSSS, NSCS and ICE SPERW refer to design and execution standards, and their own revisions will follow.
• ✓Loads in design briefs: wind, snow and temperature values quoted to contractor designers, which climate factors in the National Annexes will change.
• ✓Contractor-designed elements: the design standards the contractor must use and the edition, which must match the design basis.

Masters and standing text

The reference that matters most is the one nobody remembers writing. A practice master typically contains clauses from several authors over a decade, with design standards cited in different forms: a number in one, a title in another, an edition in a third. The first task of a transition is to find them all. That is a search problem, then a decision problem: for each reference, state which generation it will refer to, when the change takes effect and who approves it. Only after that is it a drafting problem.

Two failure modes

Two failures are worth naming. The first is partial update: a master moved to the new generation in the design basis but not in the clauses that quote clause numbers. The result is a specification that cites a standard its own design basis no longer uses, which is the pattern behind orphan references. The second is silent mixing: an engineer designs the frame to the first generation and a contractor designs a connection to the second, because the specification said "current Eurocodes". The wording "current" will mean different things in 2027 and 2029.

What should a practice do between now and March 2028?

Audit every reference, adopt a written policy on which generation each project uses, train the team, then update the masters once the UK National Annexes are published and keep a dual-reference method for projects that straddle the dates.

A practice has about sixteen months between this guide's date and the Date of Withdrawal. The National Annexes arrive late, so most of the work that can be done now is preparation, not conversion. A sequence that works:

Dual references

For a period, a practice will run projects on both generations. The simplest control is a design basis clause that names the generation and edition explicitly, backed by a master that holds both sets of reference text under a switch the project engineer must set. Avoid wording like "current Eurocodes", which has no fixed meaning during the coexistence period. Do not blend clauses from the two generations in one design: IStructE is explicit that mixing is to be avoided.

Projects that straddle the dates

A project designed in 2026 and built in 2028 raises the awkward question. The simplest rule is that the design standard is fixed at the date of the design basis, recorded in the specification, and that any contractor-designed element uses the same one. A change of generation mid-project should be a deliberate variation, not a drift. Take legal or insurance advice on whether a contract naming first-generation standards by edition remains acceptable after 30 March 2028.

What do clients and contracts need to say?

The contract documents should state the design standards and editions, say which generation applies, require contractor designers to follow the same basis, and set a procedure for changes. A reference to current standards without a date is not enough during the transition.

The specification is only one of the documents that names standards. The employer's requirements, the consultant's appointment, the CDP design briefs and the warranty or insurer requirements may all do so. If they disagree, so will the people working to them.

Appointment

State the design standards the consultant will use and that the first or second generation applies, with any exceptions. Record the date of the choice.

Employer's requirements and design brief

Name the standards and editions the contractor's designers must use, with the National Annexes. Say how changes to the standards after the base date are handled.

Specification

Fix the design basis and every reference to the same generation. State the order of precedence between the specification and any national specification.

Warranty and insurance

Confirm that the provider accepts the generation chosen. Take advice from the warranty provider and the insurer.

Building Safety Act information

On a higher-risk building, record the standards used in the information that forms part of the golden thread, so later reviewers can see the basis.

An illustrative form of words, to adapt: Design shall be in accordance with the first-generation EN Eurocodes and their UK National Annexes current at [date], and shall not be mixed with the second-generation Eurocodes. Contractor-designed portions shall use the same design basis unless the Engineer agrees otherwise in writing. The mirror clause for a project using the second generation would name the standards and Annexes by edition. The form of words is illustrative, and the choice of generation is the engineer's decision.

Who decides?

The decision is rarely the structural engineer's alone. The client, the principal designer, the contractor and the insurer all have an interest. Raise it early, record the decision and tie it to the design responsibility matrix. The design responsibility matrix guide sets out how, and NSSS explained and how to write a structural specification show how the national specifications fit under the decision.

Questions engineers ask about the second-generation Eurocodes

When do the second-generation Eurocodes become mandatory in the UK?

There is no single mandatory date in the sense of a statute. BSI withdraws the first-generation adoptions and National Annexes on 30 March 2028, and until then the first generation remains the applicable set unless the project says otherwise. Adoption also depends on contracts and Approved Documents.

When will the UK National Annexes be published?

BSI's target is to have all UK National Annexes available by 30 September 2027, aligned with the Date of Publication. Each second-generation Eurocode must be used with its National Annex.

Can first- and second-generation Eurocodes be mixed in one design?

IStructE does not encourage it. BSI's position is that using provisions from the second generation with the first is not precluded but should be done with care, and only where the result does not lower reliability below the first-generation minimum.

What are the main changes in Eurocode 2?

EN 1992-1-1 absorbs bridges and liquid-retaining structures, introduces new mechanical shear and punching models, simplified anchorage and lap rules, Exposure Resistance Classes for durability and new annexes including recycled aggregate. The UK is expected initially to keep the BS 8500 approach to durability.

What are the main changes in Eurocode 3?

EN 1993-1-1 extends the scope to steel grades up to S700, with EN 1993-1-12 covering up to S960, revises the contents, adds a new lateral-torsional buckling method and adds new parts 1-13 and 1-14, among other changes.

What should a specification say about Eurocodes during the transition?

State the generation, the edition and the National Annex edition, require contractor designers to use the same basis, and avoid references to current Eurocodes without a date. Record the decision in the design basis and the project record.

Where Avoice fits

Eurocode transition is mostly a reference-control problem: finding every place a standard is cited, deciding what each should say, and keeping the answer consistent.

In Avoice, standards sets hold the standards a specification may cite as a governed list, practice Rules can require that every standard reference carries its edition, and the office master keeps the practice's design basis wording in one place so that a change is made once. The pre-issue Technical Review compares the specification against schedules and drawings, which helps find a clause that still cites a generation the design basis has moved off. Avoice now writes structural as well as architectural specifications, so the same controls apply across a project's disciplines.

The engineer chooses the generation and approves each change. Software can find the references, hold the text and flag the inconsistency.