Renovations by a shareholder: what you can do and when to notify
In this article
A kitchen renovation, a new bathroom or a wall knocked through: the apartment is in the shareholder’s possession, but some of its structures and systems are the housing company’s responsibility. That is why many renovations are not simply a matter between the shareholder and the contractor. Before you start, it is worth finding out what you can do yourself, when you must notify the housing company in advance and who will be responsible for the change later on.
The right to carry out alterations is broad
Under chapter 5, section 1 of the Limited Liability Housing Companies Act (asunto-osakeyhtiölaki, 1599/2009), a shareholder has the right to make alterations to their apartment at their own expense. The alteration must be in line with the use specified in the articles of association, and the shareholder must ensure that the work is carried out in accordance with good building practice.
What matters is not what the renovation is called but what the work affects. Painting a wall is a different matter from removing a wall or altering the water supply, drains, electrics or ventilation.
When is an alteration notice needed?
The shareholder must notify the board or the property manager of the alteration work in writing in advance if the work may affect a part of the property, building or apartment that is the responsibility of the company or another shareholder, or the use of another apartment (chapter 5, section 2). The notice must contain the information the company needs to assess whether good building practice is being followed and whether the work could cause damage or nuisance.
A notice is typically needed at least for:
- bathroom and sauna renovations
- kitchen renovations involving water, drainage, electrical or ventilation work
- removing walls and other work affecting the structure
- changes to waterproofing, pipework or ventilation
- replacing floor coverings, if this may affect impact sound insulation
- installing an air-source heat pump
- alterations to the balcony.
The list is not exhaustive. If you are unsure, ask before the work begins. Notifying after the event is awkward, because part of the work is already hidden inside the structure.
How the company deals with the notice
The company must deal with the notice without delay and tell the shareholder whether the work is permitted and on what conditions, or whether it is prohibited (chapter 5, section 4). A refusal must be justified, and the shareholder can ask for the reply in writing. Work may not begin until the company has had a reasonable time to deal with the notice, unless the company agrees to an earlier start.
The company or another shareholder may set conditions for the alteration work if they are needed to prevent or compensate for damage to the building or other nuisance (chapter 5, section 3). A condition might be, for example, a specific plan, a certified waterproofing installer or supervision. The work can be prohibited if it would be unreasonable when the resulting nuisance is weighed against the benefit to the shareholder. If the shareholder considers the prohibition or conditions unreasonable, the matter can be taken to court.
If the alteration requires a permit from the authorities, the board applies for it or authorises the shareholder to do so. The shareholder pays the costs of the permit.
Supervision and costs
The company has the right to supervise the work to make sure it is carried out without damaging the building, in accordance with good building practice and in line with the conditions set (chapter 5, section 7). The shareholder pays the necessary and reasonable costs of supervision and of dealing with the notice.
Supervision does not transfer responsibility to the company: the shareholder remains responsible for ensuring that the work they commission is done properly. Read more in the article on renovation supervision in a housing company.
If a defect that is the company’s responsibility comes to light during the renovation, such as structural moisture damage, stop that part of the work and notify the company immediately. A shareholder must report without delay any defects that the company is responsible for repairing.
Who is responsible for the alteration later?
An amendment to the law (535/2026) that came into force at the beginning of October 2026 clarified responsibility: the shareholder is responsible for maintaining the alteration and for any extra maintenance costs the alteration later causes the company (chapter 5, section 1). If, for example, the company has to demolish a shareholder’s bathroom that is of a higher standard than the basic level during a pipe renovation, the extra costs fall to the shareholder.
According to the government proposal (HE 34/2026), this responsibility lies with whoever owns the shares at the time, not just the shareholder who made the alteration. A buyer is therefore also responsible for maintaining alterations made by the previous owner. However, liability for damages arising from the previous owner’s mistakes does not pass to the buyer.
The exception is where an installation made by the shareholder is comparable to a measure the company has carried out itself or accepted as its responsibility, and the company has been able to supervise how it was done (chapter 4, section 2). In that case, maintenance may be the company’s responsibility. This is assessed case by case, and documentation plays a major role.
Document the work
Keep the alteration notice, the company’s reply and conditions, the plans, the supervision report, material details, contractor details and photos of each stage of the work. In particular, photograph the structures, penetrations, pipes and waterproofing before they are covered. If water damage occurs or the apartment is sold ten years from now, a documented renovation is easy to look into; an undocumented one is not.
The company is required to keep records of alteration work, and this information is also given in the property manager’s certificate (chapter 7, sections 27 and 28). Your own records as a shareholder are still valuable.
Example: an air-source heat pump
An air-source heat pump looks like a simple appliance, but installing one involves penetrations through the facade or balcony structures, siting the outdoor unit, managing condensation water, noise and the appearance of the building. It is a typical alteration that is notified in advance and for which the company can set conditions. Placing the outdoor unit on a facade in the company’s possession requires the company’s consent. Good practice is to give the company an installation or commissioning report once the work is done.
Checklist before you renovate
- Is the space under my control by virtue of my shares?
- Could the work affect the structure, pipes, electrics or ventilation?
- Could the work affect another apartment?
- Is an alteration notice or a permit from the authorities needed?
- Is a designer or a qualified professional needed?
- Has the company had time to deal with the notice?
- Have I documented the work so that a future owner will also understand what has been done?
The most common mistake is to start work before notifying, because the contractor is already on site. Others include removing structures without investigating first, forgetting to document the work and failing to look into the previous owner’s renovations when buying the apartment. Responsibilities are covered more broadly in the article on the housing company division of responsibilities.
Sources
- Limited Liability Housing Companies Act 1599/2009, Finlex (in Finnish) (opens in a new tab)
- Government proposal HE 34/2026 vp, eduskunta.fi (in Finnish) (opens in a new tab)
This article provides general information and does not replace case-specific legal or technical advice.
