What the Build Year Actually Tells You: Construction Eras to Check, Country by Country
Published on: September 7, 2026
Last reviewed: September 2026. General background about construction regulation and known material issues, not an engineering assessment or a safety opinion on any specific building.
Quick answer:
- The build year is not a proxy for quality. It is a pointer to which code, which materials and which supervision regime were normal in that country in that decade.
- In earthquake countries one date splits the whole market: June 1981 in Japan, 1998 and 2018 in Türkiye, 2003 in Italy, 1985 and 1995 in Greece.
- Separately, specific materials have specific eras: aluminous cement in Spain, RAAC in the UK, polybutylene and aluminium wiring in the US, leaky envelopes in New Zealand.
- Treat anything permitted before 2000 as potentially containing asbestos, because bans stopped new installation, they did not require removal.
- A property can be legal today because of an amnesty, which is not the same as having been built correctly. Ask which document makes it legal.
"How old is it?" is the second question most buyers ask, right after the price. It is also the question whose answer travels worst across borders.
A 1978 building in Japan sits on the wrong side of the single most consequential date in Japanese property. A 1978 building in Rotterdam is unremarkable. A 1965 apartment in Barcelona belongs to the era of a specific structural problem with a name; a 1965 apartment in Copenhagen does not. A 1988 flat-roofed block in Britain may contain a material now the subject of a national survey programme; a 1988 flat-roofed block in Portugal will not.
The build year is not a proxy for quality. It is a pointer to which regulatory regime, which materials and which construction practices were normal in that country in that decade. Read correctly it tells you what to inspect, what to price and what to walk away from. Read as a simple age, it tells you almost nothing.
One framing note before the tables. This is a list of eras worth checking, not a list of properties to avoid. A well-maintained and properly retrofitted pre-code building can outperform a badly built new one, and a great deal of the world's most desirable housing predates every code in this article. The point is to know which question applies before you make an offer, and to price the answer rather than discovering it later.
Part 1: seismic code thresholds
In earthquake countries, this is the most important date in the file. Codes were typically rewritten after a specific disaster, and the resulting threshold splits the housing stock into groups that lenders, insurers and buyers treat very differently.
| Country | Key thresholds | What the threshold means in practice |
|---|---|---|
| Japan | 1 June 1981 (shin-taishin, new standard) and June 2000 (wood-frame revision) | Buildings permitted before June 1981 are kyū-taishin, designed to a materially weaker standard. The 2000 revision added foundation and connector requirements specifically for wooden houses, so for a detached timber house the 2000 date matters almost as much as 1981. Crucially, the reference is the date on the building confirmation certificate (kenchiku kakunin), not the completion date, so a building finished in 1982 can still be old-standard. Mortgage terms, earthquake insurance premiums and resale liquidity all track these lines. |
| Türkiye | Regulations in 1947, 1953, 1961, 1968, 1975, 1998, 2007, and the current TBDY published in March 2018 and in force from 1 January 2019. Separately, the building inspection system under Law 4708 began in pilot provinces in 2001 and was extended nationwide in 2011 | The 1998 regulation is widely treated as the first modern one, and the 1999 Marmara earthquakes are the dividing line in most buyers' minds. Two dates matter, not one: the design regulation in force, and whether the build fell inside the independent inspection regime. A 2005 building in a pilot province and a 2005 building outside it were supervised differently. |
| Italy | 1974 (Law 64 began progressive reclassification of seismic zones), 2003 (an emergency ordinance extended seismic classification to the whole national territory), then the 2008 and 2018 technical norms | Before 2003, whether a building was designed to seismic rules depended on whether its municipality happened to be classified at the time. Two buildings of the same year in different comuni can be very different. Ask which zone the municipality was in on the date of the permit. |
| Greece | 1959 (first code), 1985 (supplement), 1995 (new generation), 2000/2003 (EAK), Eurocode 8 in force alongside it from 2012 | The conventional vulnerability bands used in Greek engineering studies are: pre-1959 no code, 1960 to 1985 low, 1986 to 1995 moderate, 1996 onwards high. Athenian apartment stock is heavily concentrated in the low and moderate bands. |
| Portugal | The 1958 and especially the 1983 structural and seismic regulations, later Eurocodes | Lisbon and the Algarve are the exposure. Pre-1983 buildings are the group to have assessed. |
| Spain | NCSE-94 and NCSE-02 seismic standards; the Technical Building Code (CTE) from 2006 | Seismic exposure is concentrated in the southeast (Murcia, Granada, Alicante). The CTE is the broader dividing line for energy, fire, acoustics and accessibility. |
| Chile | Post-1985 revisions, and the post-2010 amendments after the Maule earthquake | Chilean practice is strong by international standards; the question is which revision. |
| Mexico | The 1985 Mexico City earthquake produced the 1987 code, with major revisions in 2004 and after 2017 | Soil zone in Mexico City matters as much as the code year. |
| New Zealand | 1976 loadings standard, the 2004 Building Act, and the earthquake-prone building system that followed the Canterbury sequence | Councils maintain earthquake-prone building registers, which are searchable. |
| United States | Regional. California's post-1971 and post-1994 changes, unreinforced masonry ordinances, and city-level soft-storey retrofit rules; the Pacific Northwest and the New Madrid zone have their own histories | Check the local jurisdiction's adopted code version and any retrofit ordinance that applies to the building type. |
Part 2: material and defect eras
These are not code questions. They are "this specific material was normal here in these years and has since turned out to have a problem" questions.
| Issue | Where | Era | What to do |
|---|---|---|---|
| Aluminous cement (aluminosis) | Spain, and to a lesser extent elsewhere in Europe | Widely used roughly 1950s to 1970s, principally in precast floor joists; prohibited for structural use in Spain during the 1970s | Brought to public attention by the 1990 collapse of a residential block at Turó de la Peira in Barcelona. Widely cited estimates put affected Spanish dwellings in the hundreds of thousands. Heat and humidity accelerate deterioration, so Mediterranean coastal stock is the exposure. Detectable by laboratory testing of a core sample, and often flagged by the periodic building inspection (ITE). Insurers frequently exclude it. |
| RAAC (reinforced autoclaved aerated concrete) | United Kingdom | mid-1950s to mid-1990s, with isolated later use | Lightweight precast panels, mainly in flat and shallow-pitched roofs. Design life commonly cited at around 30 years, and it can fail with little visible warning. Public-sector surveying has been extensive since 2023; residential guidance for Scotland was issued in January 2026 and the issue was debated in Parliament the same month. If the property is post-war with a flat or shallow roof, especially on an estate of similar units, have a surveyor check specifically. |
| High alumina cement | United Kingdom | Withdrawn from structural use in the mid-1970s after roof collapses | Mostly a concern in precast concrete beams of that period. |
| PRC (precast reinforced concrete) system-built houses | United Kingdom | Post-war to 1960s | Specific types were formally designated defective under the Housing Defects Act 1984. Lenders often refuse them unless repaired to a certified structural scheme, which makes resale, not safety, the primary risk. |
| Mundic block | Cornwall and west Devon, UK | Roughly 1900 to 1950s | Concrete made with mine-waste aggregate. A graded Mundic screening report is a standard lending requirement in the affected area. |
| Large panel system housing | Poland (wielka płyta), Czechia and Slovakia (panelák), Hungary (panelház), eastern Germany (Plattenbau), former USSR (khrushchyovka and later series) | 1950s to 1980s | Not inherently unsound, and much of it has been comprehensively refurbished with new insulation, panel-joint repair and lifts. The variables are which series, whether the joints and wall ties were remediated, and the financial health of the owners' association. |
| Asbestos | Almost everywhere | UK: blue and brown banned 1985, white November 1999. EU-wide ban from 2005, with several member states banning earlier. Australia 2003. Canada 2018. Still legal in several producing countries | The practical rule of thumb in the UK is to treat anything built or refurbished before 2000 as potentially containing asbestos. France requires an asbestos diagnostic for properties whose building permit predates July 1997. Bans stopped new installation; they did not require removal, so legacy material sits in a very large share of the world's housing. |
| Lead paint and lead pipes | Widely | Lead paint banned for residential use in the US in 1978, in the UK progressively earlier; lead supply pipes common in pre-1970 UK and pre-1986 US plumbing | Relevant to renovation planning and to families with young children. |
| Aluminium branch wiring | United States and Canada | Roughly 1965 to 1973 | An insurance and inspection question more than a structural one. |
| Polybutylene supply piping | United States | Roughly 1978 to 1995 | Failure-prone; often an insurer's question. |
| Synthetic stucco (EIFS) without drainage | United States | 1980s and 1990s | Moisture intrusion behind the cladding. Specialist moisture survey. |
| Imported defective drywall | United States, mostly Gulf and southeastern states | Imports concentrated around 2001 to 2009 | Corrosion of wiring and coils, odour. Largely litigated and remediated but still occasionally encountered. |
| UFFI (urea-formaldehyde foam insulation) | Canada, some of Europe | Around 1975 to 1980 | Disclosure item in Canadian transactions. |
| Kitec plumbing | Canada | 1995 to 2007 | Class-action history; commonly an insurance and disclosure question. |
| Leaky building envelopes | New Zealand, some of Australia | Roughly late 1980s to mid-2000s | Untreated timber framing behind monolithic cladding without a drained cavity. A weathertightness report is standard practice in the affected stock. |
| Combustible external cladding | UK, Australia, UAE and others | Mainly 1990s to 2010s on mid and high-rise buildings | Post-Grenfell, UK buildings above certain heights are subject to a remediation and safety regime under the Building Safety Act 2022, and mortgage lenders may require external wall documentation. In apartment purchases, ask about the building's cladding status and any remediation levy before you ask about anything else. |
Part 3: energy and thermal eras
Less dramatic and more predictable, but this is where your running costs live. Each of these dates marks a step change in insulation, glazing and airtightness requirements.
| Country | Step changes |
|---|---|
| Germany | Thermal insulation regulations of 1977, 1982, 1995, then EnEV in 2002 and the Buildings Energy Act from 2020 |
| France | Thermal regulations RT 1974, RT 2005, RT 2012, and RE2020 |
| United Kingdom | Successive revisions of Part L; cavity walls became normal from the 1930s and cavity insulation from the 1970s |
| Nordics | Early and demanding standards; even 1970s stock is often well insulated |
| Southern Europe | Meaningful thermal requirements arrived late. Spanish, Portuguese, Italian, Greek and Turkish housing built before the 2000s frequently has no wall insulation, single glazing and no thermal break, which is why Mediterranean winters cost more to heat than northern buyers expect |
| Japan | Insulation standards were long voluntary for housing and were tightened substantially in the 2020s. Older Japanese housing is often notably poorly insulated for the climate |
Every EU sale and letting requires an energy performance certificate, and the certificate contains the construction year and the actual measured or modelled performance. It is free to read and it is the fastest sanity check on any claim about how warm a place is.
Part 4: amnesty and informal-build eras
A separate category, and one that catches foreign buyers repeatedly. Several countries have run periodic schemes legalising buildings or extensions that did not comply with planning rules when built. A property can therefore be legal today because of an amnesty, which is different from having been built correctly.
- Türkiye: the 2018 zoning amnesty (imar barışı) issued building registration certificates for a very large number of non-compliant structures. A registration certificate is not the same as a building permit and occupancy permit (iskan). Ask which documents exist.
- Italy: successive condono edilizio schemes in 1985, 1994 and 2003, plus a 2024 decree easing certain minor internal irregularities. Italian conveyancing turns heavily on whether the built state matches the deposited plans (conformità urbanistica e catastale).
- Greece: a series of statutes settling arbitrary constructions and unauthorised conversions, with an engineer's certificate now required at sale.
- Spain: properties out of ordinance (fuera de ordenación), and regional regimes such as Andalusia's recognition of assimilated out-of-ordinance status for older rural builds.
- Portugal, Cyprus, the Balkans and much of Latin America run comparable regimes under different names.
The practical test is always the same: does the physical building match the registered and permitted plans, and if not, under what document is the difference legal? See Zoning Checks Before Buying Property Abroad.
What to ask for, by era
| If the property is | Ask for |
|---|---|
| Pre-code seismic (Japan pre-1981, Türkiye pre-1998, Italy pre-2003 in a late-classified comune, Greece pre-1986) | A structural engineer's seismic assessment, a retrofit history with invoices and permits, and a quote for strengthening if none exists. Ask the insurer for terms before you commit. |
| Spanish, 1950s to 1970s, with precast concrete floors | A laboratory test for aluminous cement, plus the building's periodic inspection report (ITE or IEE) and the owners' association minutes for the last five years |
| UK, post-war, flat or shallow roof | A specific RAAC check by a surveyor, and for anything system-built, confirmation of the construction type and whether it is a designated defective type |
| Any apartment in a mid or high-rise built or reclad since the 1990s | The building's external wall and fire safety documentation, plus any remediation programme and how it is being funded |
| Pre-2000 anywhere (pre-1997 permit in France) | An asbestos report before any renovation is planned, not after |
| Central or eastern European panel-built | The series and refurbishment history, the association's reserve fund, and whether panel joints and wall ties have been remediated |
| North American, 1965 to 1995 | Electrical panel type and branch wiring material, supply pipe material, and cladding type |
| Anything relying on an amnesty | The specific certificate, plus written confirmation from a local architect or surveyor that the built state now matches the registered state |
Frequently asked questions
Is a newer building always safer?
Not automatically. Newer means built to a later code, which is a genuine advantage in seismic countries. It says less about workmanship, materials and supervision, which is why the inspection regime in force matters alongside the design regulation. A well-maintained 1990s building can be a better proposition than a rushed 2015 one.
Does the build year on the listing match the legal date?
Often not. Listings usually quote the completion year. The date that determines which code applied is normally the permit or building confirmation date, which can be one to three years earlier. In Japan this distinction is decisive; ask for the certificate.
How much does it cost to check?
A specialist structural or seismic assessment is typically a low four-figure sum, and a materials test considerably less. Against a purchase price and the cost of the remediation it might reveal, it is the cheapest line in the transaction.
Is a defective-era property always a bad buy?
No, and treating it that way is how buyers overpay for mediocre new stock. Many of these issues are known, priced, remediable and remediated. What you want is to identify the issue, get it quantified in writing, and reflect it in the price rather than inherit it unpriced. See Renovation Cost per Square Metre by Country.
Does this affect resale?
Frequently more than it affects safety. Where lenders decline a construction type or insurers exclude a defect, your future buyer pool shrinks to cash purchasers, which shows up in the exit price. See How Long It Takes to Sell a Home, by Country.
Keep reading on JanusHermes
Ask for the permit date rather than the completion year, then ask the one question that belongs to that era and that country. A structural or materials check costs a fraction of what it can take off the price, and it is the difference between buying a known quantity and inheriting an unpriced one. JanusHermes lists property from local agencies in 11 languages, with the local agency's own contact details on every listing.
Related reading: How Long Houses Last, by Country, Renovation Cost per Square Metre by Country, Zoning Checks Before Buying Property Abroad, The Property Inspection Gap, The Overseas Home Insurance Claim Guide and How to Hire a Real Estate Lawyer Abroad.
This article is general background information about construction regulation and known material issues in different countries. It is not an engineering assessment, a safety opinion or professional advice, and it cannot tell you anything about a specific building. Dates, code versions and remediation regimes vary by region within countries and change over time. No property should be bought or rejected on the basis of its construction year alone. Commission a qualified local structural engineer, surveyor or building inspector for any property you are seriously considering.
