[Field Report] "It's Made of Wood - What If There's a Fire?"... A Preview of Korea's First Wooden Apartment

Test Building Opens at Commons Jongam in Seongbuk-gu, Seoul
As Strong as Concrete, but One-Fifth the Weight
Scan Barcodes and Assemble One Floor Every Two to Three Days
Charred Surface Keeps Flames Out
Exterior Insulation and Heat Pumps Minimi

"At first, when I heard they were building an apartment building out of wood, I was scared it would catch fire. But then I saw on TV that when a fire breaks out, steel frames simply melt and collapse. They say this wood is compressed, so it takes a long time to burn. That gives us plenty of time to get out. Wood is good for your health, and this is the site of my home for more than 30 years. When I heard they were building a wooden apartment with just 18 households, I raised my hand right away. Since it's the first of its kind in Korea, I think it will become a landmark for the neighborhood."

Kim Jeongja, an 80-year-old member of the Gaewunsan Maeul Cooperative, said this on Nov. 4 as she toured the wooden apartment test building unveiled that day at the site of the Gaewunsan Maeul small-scale housing redevelopment project in Jongam-dong, Seongbuk-gu, Seoul. The test building was constructed to verify the construction method and performance before work begins on Korea's first high-rise wooden apartment building.

Construction of the test building for the wooden apartment complex "Commons Jongam" in Jongam-dong, Seongbuk-gu, Seoul. Gaewunsan Maeul Association.

The Commons Jongam apartment complex will be built here, a 10-minute walk from Gireum Station on Subway Line 4. The project covers a 5,097-square-meter site and will comprise three buildings, with three basement levels and 20 floors above ground, and a total of 130 households.

Rather than borrowing a construction company's brand, the residents' cooperative created its own apartment brand, Commons, meaning "shared assets," the first time a brand has been developed directly by a cooperative for a redevelopment project in Korea. It added the neighborhood's name to the brand. Construction began in September 2025, and reinforced-concrete work is currently underway on the basement levels and standard residential units.

Of the 130 households, 18 units will be built with wood and have an exclusive floor area of 95 square meters. The structure will first be built in reinforced concrete up to the floor of the fourth story above ground. Starting in May 2027, 10 to 13 floors will then be built on top using timber.

A cross-sectional model of a wall, unveiled on the 4th at the test building for the Commons Jongam wooden apartment complex in Seongbuk-gu, Seoul. It is thicker than a standard wall, with multiple layers of insulation, fire-resistant gypsum board and other materials added to the structural timber. Photo by Choi Seoyun

The two-story test building unveiled on Nov. 4 is a full-scale mock-up built ahead of the main construction work to verify the joints between concrete and timber, sound insulation, and fire resistance. The cooperative plans to begin the main timber assembly and sales of units to the general public in May 2027. Residents are scheduled to move in when construction is completed in June 2028, when operations as a social cooperative will also begin.

SWECO, the Swedish firm collaborating on the design, considered a test building unnecessary, saying the construction method had already been proven in Europe. However, the cooperative and construction team went ahead with it, saying they needed hands-on experience with plumbing, wiring, and assembly methods that cannot be understood from drawings alone in order to improve quality.

Gu Jakyun, division head at Gansam Architecture, which is in charge of the design, said, "Overseas, they sometimes cut out only the part damaged by fire and replace it with a new timber component." He added, "We will incorporate into the main design the data gathered by building and then dismantling the test structure, and construct an apartment building that can last at least 50 years."

Of the 18 wooden apartments, around 10 units are expected to be offered for sale to the general public after the units allocated to original residents are excluded. The number may change slightly depending on the process for revising member allocations. The plan is to price the units at 90% to 110% of apartment prices near Gireum Station. In September 2026, an 84-square-meter unit at Lotte Castle Classia near Gireum Station sold for KRW 1.93 billion. An 84-square-meter unit at Raemian Gireum Centerpiece sold for KRW 1.91 billion in August 2026.

Inside the test building of the Commons Jongam wooden apartment in Seongbuk-gu, Seoul. To meet Korea's fire-resistance standards, the wooden walls are covered with fire-resistant gypsum board and finishing materials, leaving no wood exposed. Photo by Choi Seoyun

Concerns about structural strength and fire safety are often raised when it comes to building high-rise apartments out of wood. The apartments will be built using cross-laminated timber (CLT), a specialized material made from spruce boards imported from Austria, stacked in alternating directions and compressed under high pressure. The exposed cross-section of the timber in the test building showed layers pressed tightly together, with a thickness of about one adult handspan. The timber can withstand a compressive strength of 24 MPa (megapascals, equivalent to about 240 kilograms of force over an area of 1 square centimeter), the same strength as the concrete used to construct a typical 20-story apartment building.

By contrast, it weighs 490 kilograms per square meter, about one-fifth as much as concrete, which weighs 2.4 metric tons per square meter, reducing the impact on the building in an earthquake. In a fire, steel columns can rapidly melt and buckle when exposed to high temperatures, but thick, compressed timber chars on the outside, preventing the flames from spreading inward. Even when ignited, it burns slowly, at a rate of 0.53 millimeters per minute. The Korea Institute of Civil Engineering and Building Technology is also conducting a separate test to measure how long a wall made by combining timber and gypsum board can withstand fire.

Lee Youngjun, site manager at Bomi Construction, which is responsible for construction, said, "The timber itself, which is 140 to 200 millimeters thick, is strong enough to hold up. On top of that, we added three layers of fire-resistant gypsum board, each 19 millimeters thick, exceeding the legal requirement of two layers and meeting the two-hour fire-resistance standard."

The project has also addressed chronic apartment problems: inter-floor and inter-unit noise. The walls between units are filled with sound-absorbing material, or mineral wool, made by melting stone and drawing it into fibers, between layers of gypsum board. They received the highest rating, "Excellent," for blocking sound of up to 58 dB, preventing conversations or television noise from next door from being heard. The goal is to keep floor impact noise - measured by how much thumping from the floor above is transmitted to the unit below - below the legal limit of 49 dB. To achieve this, different noise-reduction materials were laid in three rooms on the second floor of the test building. The cooperative plans to select the quietest material after testing by the National Institute of Forest Science and a review of the data by researchers at Korea Land and Housing Corporation (LH).

The timber panels will be precisely cut at Stora Enso's factory in Austria to match 3D building information modeling (BIM) plans, including holes for electrical outlets and pipes, before being brought to the site. The timber will not be cut or shaved on-site. After scanning the materials' barcodes with smartphones to confirm their locations, teams of six to eight workers will assemble them like Lego blocks, completing one floor every two to three days.

Business representatives answer questions from attendees at an event unveiling the Commons Jongam wooden apartment test building in Seongbuk-gu, Seoul, on the 4th. From left: Lee Youngjun, site manager at Bomi Construction; Kim Seungwook, executive vice president at HanmiGlobal; Gu Jakyun, division head at Gansam Architecture; and Lee Wonhyung, head of the Gaewunsan Village Cooperative. Photo by Choi Seoyun

The small cooperative chose to build Korea's first wooden apartment to stand out in a housing market dominated by large complexes. It is leading the project directly, without a redevelopment project management company or a trust company, relying solely on funding loans and a project-cost guarantee from the Korea Housing & Urban Guarantee Corporation (HUG). Instead, it has partnered with HanmiGlobal, a specialist construction project management (PM) company, to apply preconstruction simulation (precon) and value engineering (VE) reviews from the design stage, reducing conflicts between construction processes and managing costs.

After seeing the 2022 apartment concrete-pouring collapse in Gwangju, the cooperative sought an off-site assembly method to reduce the risk of workplace accidents. It also felt that, in a market where 200,000 households come onto the market each year, being the first in Korea would help a standalone complex with just 130 households stand out.

However, initial construction costs were actually higher than with reinforced concrete. Had the entire complex been designed as a wooden structure from the outset, construction time could have been reduced by around 30%, saving on financing costs. But the cooperative changed only 18 units midway through the project, after obtaining permits for concrete construction, and had to bear the additional cost of a rising exchange rate while importing all the timber from Europe and specialized screws from Italy.

Instead, the cooperative has decided to compete on management fees paid after move-in and on how it operates the shared spaces. Unlike typical apartments, which have insulation only on the inside of the home and lose heat at every corner, the entire exterior of the building containing all 130 households is wrapped in insulation. It has also installed triple-glazed windows to block drafts and a ventilation system that retains indoor heat. The energy used annually to heat one square meter of floor area is equivalent to 6 liters or less of kerosene, about half the 12 to 15 liters used by a typical apartment. Individual gas boilers and gas pipes have also been eliminated. Instead, a large electric heating and cooling system that extracts heat from the outside air - an air-source heat pump - will be installed in the complex to provide heating and hot water to all households.

Unlike typical apartment complexes, which restrict entry to outsiders, the complex will open its basement-level daycare center, library, shared kitchen, neighborhood shop, and passage connecting to Gaewunsan Park to local residents. After moving in, residents will form a social cooperative to operate these facilities themselves, with plans to use the revenue to lower apartment management fees.

Lee Wonhyung, head of the cooperative, said, "Because the wood itself is a high-performance insulator, warmth can be maintained just by the residents' body heat and heat from household appliances, so heating and cooling costs will be almost negligible."

Bird's-eye view of Commons Jongam in Seongbuk-gu, Seoul. Gaewunsan Maeul Cooperative

Although the private cooperative is undertaking a low-carbon construction experiment despite rising construction costs, support from domestic regulations and the public sector has been slow to materialize.

In Europe, wood can be left exposed indoors as long as a building meets the standard for not collapsing in a fire. In Korea, however, wood must be enclosed in gypsum board to ensure it retains its original thickness and strength even during a fire. As a result, despite being a wooden apartment, the timber will not be visible indoors except on one wall of the living room.

Although the building prevents heat loss like a thermos and uses high-efficiency electric equipment to cut energy consumption by more than half, it has not even received the lowest grade under the zero-energy building rating system. This is because the current evaluation system awards points mainly based on how many solar panels are installed on the roof, rather than the building's own insulation performance.

Lee, head of the cooperative, said, "Because this is the first attempt of its kind in Korea, with no precedent, it is disappointing that the government and relevant research institutions hesitate to participate, worried that something might go wrong, even when we propose technical collaboration." He added, "I hope that if we build the first structure and generate demonstration data, the systems and technology will follow."

This content was produced with the assistance of AI translation services.