Walk into the lobby of a residential block in Wood City Jätkäsaari and the first thing you notice, before the lift, before the postboxes, is the smell. It is the smell of a Finnish forest in the third week of June. The walls show exposed engineered timber. So does the ceiling. The fire-rated stairwell, which by Finnish regulation must be encased in a non-combustible lining, is one of the few places in the building where you cannot see the wood at all. Eight storeys above, the smell is fainter, but it is still there.
This is not, by Finnish standards, a luxury building. The two residential blocks at Wood City were built for ATT, the City of Helsinki’s own housing-production company, and let as state-supported rental housing through the same channels as any other affordable flat in the city. The novelty is structural. The blocks are built from laminated veneer lumber — LVL — and the residents who took the keys from 2019 onwards are among the largest cohort of urban Europeans now living, daily, inside a tall engineered-timber building of any considerable size.
What changed in the building code
None of this would have been buildable a generation ago. From 1997, a revision of the fire code had permitted timber-framed residential and office buildings of up to four storeys — a cautious opening, in line with the European fire-protection consensus of the time. The decisive change came in the spring of 2011, when the Finnish authorities revised the fire regulations to allow timber-framed residential and workplace buildings of up to eight storeys, subject to conditions: sprinkler systems, encapsulated escape routes and defined fire classes. The relevant section of the old National Building Code of Finland was E1, “Fire safety of buildings”; it has since been superseded by the Ministry of the Environment’s Decree 848/2017, in force from the start of 2018 and amended in 2021.
The 2011 reform did not arrive in a vacuum. VTT, Finland’s state technical research centre, had been running fire-test programmes on engineered-timber assemblies for years, and the rescue services — the pelastuslaitos — had their own test data. The encapsulation requirement, the sprinklers, the limits on exposed surface: each was a negotiated answer to a documented worry. By the time the eight-storey ceiling was lifted, much of the fire community had stopped objecting, because the conditions attached to the permission were the conditions it had asked for.
The proof of concept in Jyväskylä
If Wood City is the showpiece, the proof of concept sits two hundred kilometres north, in the Kuokkala district of Jyväskylä. There, the architecture office OOPEAA — the Office for Peripheral Architecture, founded by Anssi Lassila — completed Puukuokka One in 2015: Finland’s first eight-storey wooden apartment building, and the project still most often shown to visiting delegations. Unlike Wood City, Puukuokka is built from cross-laminated timber, assembled from prefabricated volumetric CLT modules, two to a flat, craned into place so that each block could be raised in a matter of months.
The full Puukuokka block, completed in three phases by 2018, houses well over a hundred households as affordable rental homes. It demonstrated the two things the rest of the country needed to see: that a timber high-rise could meet the new fire classes, and that modular CLT could be built quickly enough, and cheaply enough, to compete inside the economics of subsidised housing. The architects who learned to work within these constraints — OOPEAA among them — are now disproportionately fluent in a way that most European practices are not.
The conditions attached to the permission were the conditions the fire community had asked for. The eight-storey ceiling did not arrive in a vacuum; it arrived in a building code.
National Building Code of Finland, section E1, “Fire safety of buildings”
The carbon ledger
The technical case for engineered timber in housing rests largely on embodied carbon: the emissions locked into a building before anyone moves in. A reinforced-concrete mid-rise block carries a heavy construction-phase footprint in its cement and steel; a comparable timber block, by the published estimates the industry and VTT both work from, carries substantially less, the precise margin depending on whether the timber is domestic, how the foundations are built and how the concrete that remains — the plinth, the cores, the stair shafts — is specified. On a single residential block the saving is not trivial, and across a public housing pipeline it compounds.
The second argument, biogenic sequestration, is genuinely contested. Timber panels hold carbon drawn from the forest for as long as the building stands. How to count that in a national inventory — as a permanent saving, a temporary stock, or something hedged in between — is a live methodological dispute, and Finland’s own position has tended to count it conservatively. The European Commission’s guidance on whole-life carbon, and the EU taxonomy that increasingly shapes what developers can finance, sit somewhere in the middle. The honest summary is that the embodied-carbon case is solid and the sequestration case is real but unsettled.
The supply chain that moved
A timber-construction programme assumes a timber supply chain, and Finland has one of the strongest in Europe; forestry and its products are a substantial slice of national exports. The Russian invasion of Ukraine reshaped the arithmetic. Russian roundwood and wood chips, which before the war made up roughly three-quarters of Finland’s relatively modest imports — on the order of a tenth of the wood the country’s mills consume overall — effectively stopped around July 2022, as sanctions and Finnish buyers’ own decisions took hold. By the third quarter, log and chip imports from Russia had fallen, in practical terms, to zero.
The market response was rapid and instructive. Prices for Finnish-origin spruce and pine rose through 2022, then eased as the domestic harvest expanded and feedstock from Sweden and the Baltic states partially backfilled. The CLT industry that absorbed this was small and concentrated. CrossLam Kuhmo, in the eastern town of Kuhmo, opened Finland’s first dedicated CLT plant in 2014 and doubled its capacity in 2023, drawing pine and spruce from forests within roughly eighty kilometres of the factory — a degree of local sourcing that turned out to be a hedge against exactly this kind of shock. It is worth being precise about the larger names, because they are routinely confused: Stora Enso’s Varkaus mill produces LVL, not CLT; the company’s cross-laminated timber comes from Gruvön in Sweden and from its Austrian plants. Metsä Wood’s engineered product is Kerto LVL, not a CLT line.
Money, and what ARA can and cannot do
The institution that quietly shapes all of this is ARA — the Housing Finance and Development Centre of Finland, the agency that underwrites and subsidises affordable rental housing. ARA does not build, but its financing terms decide what gets built, and a building-cost shock of the kind that arrived in 2022 lands directly on the projects it funds. Timber blocks, with their longer supply chains and their exposure to a feedstock market in upheaval, were among the most sensitive. The programme’s survival through that period owed less to any single architectural triumph than to the unglamorous fact that a public financier kept funding the pipeline while costs were moving.
That is also the part of the story most prone to exaggeration abroad. Helsinki has not legislated a CLT default; it has built a handful of genuine, occupied, affordable timber blocks, watched the costs, and kept going. The residents’ experience is mixed in the honest way real buildings are: the warmth and the smell are widely liked, while the low-frequency footfall noise that engineered-timber floors transmit has driven a steady, incremental thickening of floor build-ups — more mineral wool, a heavier topping, better resilient mounts — in each successive cohort. The industry calls this iteration. It is simply how a young building type grows up.
What other cities can copy, and what they probably can’t
Other cities have been watching. Bavaria amended its building code, the Bayerische Bauordnung, with effect from February 2021, opening timber construction to every building class — a liberalisation that predated, rather than followed, the Helsinki conversation. In France, Bordeaux now has Hypérion, the Jean-Paul Viguier tower handed over from 2021, billed as the country’s tallest timber-framed residential building, its upper floors of CLT rising from a concrete core and base. Each of these is a local answer to a local code, not a copy of the Finnish one.
What none of them can simply import is the supply chain. CLT and LVL manufacturing scale with proximity to good structural timber and to electricity that is at least partly clean. Finland has both; much of urban Europe has neither in the right ratio at the right price. The portable parts of the Helsinki experience are the code reform and the procurement design — copy the fire classes first, the public financing second, and accept that your own supply chain will look different. The non-portable part is the forest.
What the Wood City residents will tell you, if you ask, is none of this. They will tell you that their flat smells different from any flat they have lived in before. That the sound of rain on the roof is, somehow, audible eight storeys up. That the wood walls dent more easily than they thought, and that this turns out to be fine. The building is not a demonstration project. It is a place where, for the next several decades, a few hundred people will live their ordinary lives. The carbon arithmetic, the fire classes, the supply-chain shock and the slow tuning of the floors all sit in the background of that ordinariness. The smell of the wood does not.
Sources: Finnish Ministry of the Environment (National Building Code of Finland, section E1; Decree 848/2017 on the fire safety of buildings); VTT Technical Research Centre of Finland; ARA, the Housing Finance and Development Centre of Finland; the City of Helsinki and its housing-production company ATT; Anttinen Oiva Architects (Wood City, Jätkäsaari); OOPEAA (Puukuokka, Jyväskylä); Stora Enso (LVL at Varkaus; CLT at Gruvön and Ybbs); Metsä Wood (Kerto LVL); CrossLam Kuhmo; the Natural Resources Institute Finland (Luke) on roundwood trade; the Bayerische Bauordnung 2021; and Eiffage and Jean-Paul Viguier on Hypérion, Bordeaux.
