We have created this Annex Project site to provide a central place for information and updates throughout the construction period. The site is being developed and will be updated as the project progresses and more information becomes available.

We will also publish maps showing the current traffic arrangements, access routes, and any changes affecting arrival at and departure from school. Following these arrangements helps us maintain a safe environment for students, families, staff, and visitors throughout the construction period.

Thank you for your patience and understanding during the Annex Project.

Latest News

Update 7.10.2026

Construction on the Annex project continues to move steadily upward! Recent milestones include insulating the civil defence shelter and completing the 2nd-floor hollow-core slab floor. Teams are now focused on installing 2nd-floor columns, beams, and wall elements, alongside formwork for the main concrete wall.

During the October Break, site teams will take advantage of the empty campus to perform essential infrastructure works. Please note that heavy transport and deliveries will run throughout the day without regular drop-off/pick-up restrictions, and the stairwell emergency exit route will be temporarily out of service. Key tasks during the break include drainage pipe renewals, perimeter drain installation, and relocating the electrical switchboard.

Soon after, once 2nd-floor concreting is finalized, 3rd-floor structural columns and wall elements will begin arriving on site as the building reaches its next level.

Update 18.9.2026

The construction continues to advance smoothly, with new milestones completed each week. The civil defence shelter has reached structural completion with its walls and roof in place. On the first floor, hollow-core slabs, columns, and beams have been successfully installed and grouted. In the main lobby area, construction team has also begun the formwork and reinforcement work for the large cast-in-place concrete feature wall.

Over the coming weeks, structural assembly will move rapidly up to the second and third floors. Next week, column and beam installations continue alongside reinforcement for the second-floor slabs. On Thursday UMR will pour the second-floor concrete slab, which will require a concrete pump truck to be stationed on Selkämerenpolku. Following week, work will focus on installing the second-floor wall elements, solid slabs, and hollow-core slabs, followed by concreting the main lobby wall and vertical joints. Later, preparations for the third floor will officially start as structural columns and wall elements arrive on site.

Update 4.9.2026

Great progress continues on the annex site! This week, work on the civil defense shelter floor was completed, and reinforcement for the walls is underway. The hollow-core slabs are in place with jointing work active. We are also excited that the first 1st-floor wall elements have arrived on site and will begin going up next week.

We are also celebrating the completion of the Selkämerenkatu street renovation this week, which brings a wonderful sense of safety and normalcy back to our campus surroundings!

During arrival time this Friday morning, we noticed dusty air in the main staircase. This was caused by concrete slab cutting on the adjacent annex site, which drifted inside through an exterior opening. We immediately notified site management, who stopped the work, relocated it further from the building, and sealed the opening. While the dust was harmless, it may have caused mild coughing for those with sensitive airways. Our second staircase remained fully clear and available while the main area settled.

In the coming weeks it will be exciting to see visible progress with walls, columns, and beams going up, and arrival of new staircase elements.

Update 27.8.2026

The annex is rapidly taking shape! With foundations prepared and the civil defence shelter floor pour successfully completed, the "puzzle" is officially being put together, as the first precast structural elements are now visible on the site.

Construction is officially moving upward. Crews are installing foundation wall elements this week, with 1st-floor hollow-core slab placement following shortly after.

Upcoming work over the next few weeks includes a major concrete pour and the installation of 1st-floor walls, columns, and beams.

Last Thursday's site meeting gave all participants a very thorough soaking - a reminder of the open-air conditions as structural work gets underway!

Update 14.8.2026

A Great First Week Back

It is wonderful to see our students and staff back on campus as everyone settles back into daily routines! Despite a few planned adjustments such as staggered starting times and using new entrances, things inside the main building are running smoothly making it easy to forget we’re right next to an active construction site.

While school life resumed, construction made significant strides: UMR completed concreting for the new building's foundations, the shelter walls, and the reinforcement work for the impressive cast-in-place wall to prepare for its final pour. A mobile crane alongside foundation wall pre-cast elements arrived on-site, fully setting the stage for structural assembly.

What’s Happening Now

As we move into the coming days, there will be increased activity around the site: On Monday, gravel filling for the civil defence shelter floor will take place, with deliveries along Selkämerenpolku throughout the day. There will be some noticeable noise from the conveyor belt, gravel handling, and concrete compaction equipment during foundation pours. Following the ground filling, reinforcement work for the shelter will begin, alongside assembling formwork and steel structures for the cast-in-place wall. Installation of the pre-cast foundation wall elements will officially kick off.

In the subsequent weeks, work will reach new heights - literally! The civil defence shelter structure will undergo its concrete pour, followed closely by the installation of heavy floor slabs (hollow-core slabs) for the 1st floor. Structural progress will continue right into installing the first-floor wall elements.

Update 3.8.2026

Summer Works Summary

Over the summer break, major ground and structural work was carried out across the site. This included heavy piling work - driving deep support pillars into the ground - to secure the new building's foundation. To safely reinforce the foundations beneath the main structure, the middle section of the school has been temporarily sealed off throughout the summer.

Completing this heavy, high-disruption work while school is on a break requires an exceptionally tight schedule. While the construction itself remains on track, preparing the school spaces for the new academic year is coming down to the final wire. We greatly appreciate the community’s patience and understanding as our Facilities team works up until the very last minute to ensure everything is ready for staff and students.

This Week: Preparing for the New School Term

As teachers return for orientation and students head back for the start of the school year, the primary focus on-site is making sure the school is fully safe, restored, and ready for learning. Active work is underway to restore school spaces for daily educational use, alongside a thorough final cleaning of the premises.

Foundation & Structure: Construction teams are building the wooden molds (formwork) and laying steel mesh (reinforcement) for the foundation footings, with concrete pours planned to solidify these bases. Groundfilling work is also taking place in the shelter area.

Interior & Building Work: In the main stairwell, plastering, painting, and window installations are moving forward. Work is also continuing to connect the building’s new heating system.

Looking Ahead

Over the coming weeks, interior finishing touches, such as puttying and painting in main Stairwell, will conclude. Meanwhile, structural construction will step into its next phase, focusing on concrete works for the shelter area, installing pre-cast foundation wall panels, assembling wall molds, and lifting heavy floor slabs into place.

Update 16.6.2026

As ISH offices wrap up and head into a well-deserved holiday this week, the school annex site is buzzing with energy! The quiet hallways allows UMR to safely take care of some of the heaviest and noisiest work over the break.

Here is a little look at what’s been happening behind the scenes and what’s coming up next:

What happened Past Week:

Outside: Heavy machinery has been at work, digging and prepping the ground for the new building's foundation and drainage systems.
Inside the Building: A protective wall was built in the lobby. This creates a completely isolated zone so the team can safely dismantle the old internal staircase without impacting the rest of the building. Extra helping hands have also arrived on site to finish up the safety walls on the upper floors.

In the Coming Weeks

The annex site will transition into its heaviest phase of construction. The official "piling" works will kick off to secure the foundations. Yard digging will continue, alongside some specialized diamond drilling on the ground floor to strengthen the base structures.

Once the heavy foundation work wraps up, bricklaying for a new staircase will begin.

Update 2.6.2026

Protective walls are being built inside the school to isolate the construction zones from our school and work areas.

This Week: We are kicking off interior and façade demolition, draining HVAC systems, and disconnecting electrical lines in the work zones. Outside, excavation in the yard continues, and the library wall and entrance canopy are being removed.
In the Coming Weeks: UMR will begin demolishing the interior staircase in the lobby while yard excavation continues. Heavy piling works will begin on-site, and all demolition phases are scheduled to be finalized.

The school offices continue to work for some more weeks, DP center and Main Campus are prepared for next school year, despite the significant construction site activities surrounding us.

Update 25.5.2026: report from UMR (construction company)

Last week, the site was officially established, and site office was set-up. Sewer and stormwater system connection work was carried out in the street area. On Thursday, we received the site fences at the property, and on Friday, we fenced off the construction site area.

Upcoming site activities for this last week of School:

Boarding and painting of the site fences, installation of the site gate.
Removal of paving stones and fences begins on Monday.
Removal of lighting poles.
Start of excavation works in the yard area on Wednesday.
Set up of the site sign.
Backfilling works in the street area and start of paving works on the street. Finalization / asphalt paving of the street area

Works in the first weeks of June:

Start of temporary site electrical works.
The arborist from the City of Helsinki will carry out branch thinning.
Set up of the site office continues.
Start of facade demolition works.
Construction of protective walls inside the school premises to separate the construction site from the school.
Start of interior demolition works. Start of demolition works for the interior staircase in the lobby. Demolition of the library wall and entrance canopy.
Excavation works in the yard continue.

Update 21.5.2026

As of today, the backyard has been cleared of cars and bikes, and entrance to the Main Building advised through main entrance at Selkämerenkatu, and side entrance at Messitytönkatu. Fencing started today with light fencing, closing the back entrance. Fencing work is expected to be completed latest early next week, with heavy fencing starting tomorrow.

Construction project launch meeting was held today, with participants including designers, constructors and project management, as well as ISH representatives.

A note about bikes: during the construction period, at least for now, we have no own bike racks in use. Instead, there are numerous fixed bike racks in the park adjacent to the school building and by the rocks. Our recommendation is to utilize those, taking into account that thieves do operate in the Ruoholahti area, and proper heavy duty locks are advised. Also, the School does not have surveillance access in this area, and therefore we cannot provide police assistance in case of any incidents.

Please see the map below for the location of the City of Helsinki bike racks.

Update 15.5.2026

As the Annex project progresses, updated access and traffic arrangements are planned from 21 May 2026. Please see the updated map below for student entrances, drop-off arrangements, and traffic guidance around the school area.

Following these arrangements helps us maintain a safe environment for students, families, staff, and visitors throughout the construction period. Thank you for your understanding during the Annex Project. Click the map to view the details.

Update 13.5.2026

Work at the corner of Messitytönkatu began this past Monday. Currently, a portion of the street has been excavated, but pedestrian access remains open around the work site. While this may cause some minor inconvenience, foot traffic continues to move safely and without disruption.

In preparation for the main phase of construction, we have achieved several key milestones:

Permits: The city has officially granted the necessary permits to begin work.
Safety: A fire consultant has reviewed and confirmed our temporary evacuation arrangements for the duration of the project.
Timeline: Planning for the main Annex construction site opening (behind Main Building) is on track for the end of next week.

Update 8.5.2026

Schedule Update: Messitytönkatu Corner

Work at the corner of Messitytönkatu was postponed this week due to a minor administrative delay in final permit approvals. We now expect work to commence on Monday, May 11th, or as soon as our contractor, UMR, receives the final go-ahead. Click the map to view the details

Environmental Management & Soil Cleaning

In accordance with standard city obligations, we are conducting soil cleaning. This process involves the careful handling, transportation, and sampling of soil. A formal notice regarding this work is being distributed to our neighboring buildings. The work poses no risk or danger to the environment, or people. This work will commence once digging work begins behind the school.

Update 30.4.2026

Below milestones have been updated to ensure the very latest information.

Annex Agreement Negotiations

Time and careful planning efforts have been put into ensuring our construction agreement is responsive to our needs to fully operate as a school during the period of construction (May 2026-September 2027).

The contract has been agreed upon in principle, allowing us to share the following preliminary milestones:

11.-21.5.2026, the corner of Messitytönkatu is opened to connect the annex to municipal infrastructure. Messitytönkatu street remains open for both cars and pedestrians, with one lane closed at a time. Heavy work is done before 9.00 to avoid disruptions to school work, particularly during IB exams. During this period, students can be dropped off by the Messitytönkatu park, and access school through backyard. Zebra crossing next to school (Messitytönkatu) will not be in use.
21.5.2026, fencing and digging work starts behind the school. Access to school happens through Messitytönkatu and Selkämerenkatu (front).
1.6.2026, heavy piling work commences. From this date until the end of July, there will be limited access to certain areas inside the main building.

We have been in touch with the city and the construction companies of the neighboring houses to request consideration to minimize heavy work during our IB exam period, from 27 April until 20 May.

Our Annex contract is based on a shared commitment to minimising disruption to normal school operations. It includes clear measures to limit disruption to school work, supported by ongoing communication. The construction schedule is aligned with the school year, with major works planned during the summer.

Additionally, over 1000m2 temporary space is rented to move part of the students off campus, and to allow more space in the main building to avoid spaces with a higher risk of noise. Despite all the preventative measures taken, it is important to note that a construction site will inherently cause more disruption than a standard school year.

Start of Annex Construction Site

Project officially kicks off on Monday, 18 May 2026. The period of May 18-30 is dedicated for site set-up and fencing. The School parking lot and back entrance will not be in use, and some clattering sounds may be heard from outside.

UMR is aware that IB exams are taking place until Wednesday, 20 May, and they are asked to be extra careful during those days. Noisy construction work will begin on 1 June, once school is on break.

Annex Decision and Construction Company Selection

The Extraordinary General Meeting voted to launch the Annex project on 11 March 2026. More information about the decision in Past Communications

Uudenmaan Mestari‑Rakentajat Oy (UMR) was selected as the main contractor by the Board of Governors.

Annex Project Town Hall

The Annex Town Hall took place on Tuesday, 24 February 2026 at 17.30 at ISH to introduce the project with an overview of the proposed design and its impact on teaching and learning. The meeting also covered the project timeline, financial planning, and risk management, and concluded with next steps and a Q&A session.

Town Hall materials can be found here.

Page updated

Report abuse