> What the basement tells you about the building's condition > Lähde: https://huoneistokierros.fi/en/knowledge-base/housing-company-basement/ > Koko sivusto koneluettavana: https://huoneistokierros.fi/llms-full.txt [Knowledge base](https://huoneistokierros.fi/en/knowledge-base/) # What the basement tells you about the building's condition Huoneistokierros · 12 September 2026 · 5 min read ![Spiral staircase and an arched window in a bright space](https://huoneistokierros.fi/_astro/porraskaytava-kaari.Em9X4YPF_Z1pxDTK.jpg) In this article 1. [Why changes show up in the basement first](https://huoneistokierros.fi/en/knowledge-base/housing-company-basement/#why-changes-show-up-in-the-basement-first) 2. [Signs of moisture](https://huoneistokierros.fi/en/knowledge-base/housing-company-basement/#signs-of-moisture) 3. [Ventilation and changes in use](https://huoneistokierros.fi/en/knowledge-base/housing-company-basement/#ventilation-and-changes-in-use) 4. [Pipes and penetrations](https://huoneistokierros.fi/en/knowledge-base/housing-company-basement/#pipes-and-penetrations) 5. [The source of moisture may be outside](https://huoneistokierros.fi/en/knowledge-base/housing-company-basement/#the-source-of-moisture-may-be-outside) 6. [Who is responsible for the basement](https://huoneistokierros.fi/en/knowledge-base/housing-company-basement/#who-is-responsible-for-the-basement) 7. [Basement round checklist](https://huoneistokierros.fi/en/knowledge-base/housing-company-basement/#basement-round-checklist) 8. [Find the cause before repairing](https://huoneistokierros.fi/en/knowledge-base/housing-company-basement/#find-the-cause-before-repairing) The basement houses storage rooms, technical spaces, the heat distribution room, the bicycle store and often a civil defence shelter. Few residents go there without a reason, but the basement tells you more about the building’s condition than a tidy stairwell. Moisture, ventilation problems, ageing pipes and the strain from rainwater often show up there before they appear in the apartments. ## Why changes show up in the basement first The basement is close to the ground, the foundations and the building’s technical systems. Moisture can come from outside if rainwater is not directed away, the ground slopes the wrong way or the perimeter drains are not working. It can also be generated inside if the ventilation is not working or the way the space is used has changed. The basement of an old building looks different from the technical space of a new one, and there is no single correct condition for every building. What matters is knowing what your own basement is normally like. If a damp patch or a strange smell appears in a basement that has stayed dry and odourless for years, the change should be taken seriously. ## Signs of moisture A wall that looks wet does not on its own tell you the moisture situation. There may be moisture in the structures that cannot be seen, and an old mark does not automatically mean the problem still exists. So the most important thing is to notice changes and find out what is causing them. Look out, for example, for: - a new damp patch on a wall or the floor - darkened or altered building material - white salt deposits on masonry - peeling paint, coating or render - water on the floor or moisture around pipes - a new or stronger earthy, musty or sewer smell - a previously repaired spot where the fault seems to be returning. These signs alone are not enough to establish, for example, mould damage. That requires a proper investigation. ## Ventilation and changes in use Ventilation removes moisture and impurities. In older buildings, basement ventilation is often natural (stack effect); in newer ones it is mechanical. If the air is constantly stuffy or damp, it is worth finding out whether the ventilation is working as designed. The use of a basement changes over the decades. Storage rooms are put to other uses, equipment is brought into the spaces, structures are sealed and windows or doors are altered. Every change can affect ventilation and moisture. ## Pipes and penetrations Water, drainage and heating pipes often run through the basement, so you can see their external condition there: leaks, corrosion and damaged insulation. The surface does not tell you about the inside of a pipe, but external signs can give a reason to investigate further. Also look at the ceiling and at penetrations. An old water mark does not necessarily mean a current leak, but an unexplained mark is worth investigating. ## The source of moisture may be outside Rainwater drainage, the slope of the ground, perimeter drains and the structure of the foundation wall affect how much moisture the basement walls are exposed to. A damp patch in the basement is therefore a reason to look outside too: does the ground slope away from the wall, do the downpipes work, and is there new darkening or weathering on the plinth? Autumn is a good time for a basement round, and it is also worth doing one after heavy rain. Do not go into the basement if there is water near electrical equipment or any other immediate danger. ## Who is responsible for the basement The company is responsible for maintenance insofar as it is not the shareholder’s responsibility (Limited Liability Housing Companies Act, asunto-osakeyhtiölaki, 1599/2009, chapter 4, section 2). Its responsibilities include the structures, insulation, and heating, water, drainage and ventilation systems. The basement and its structures are therefore, as a starting point, the company’s responsibility, but the articles of association can provide otherwise (chapter 4, section 1). A shareholder must notify the company without delay of a fault in their apartment that the company is responsible for repairing (chapter 4, section 8), and observations in shared spaces are best reported in the same way. The resident does not need to know the cause of the fault. For example, “there is a new dark area at the bottom of the north wall of the basement that was not there a month ago, and there is an unusual smell in the space” helps more than “there is mould in the basement”, which is already a conclusion. The Rescue Act (pelastuslaki, 379/2011) also applies to the basement. Nothing may be stored in the basement’s access routes, and easily flammable material must not be stored in a way that creates a fire hazard. The civil defence shelter must be kept in a condition that allows it to be brought into use within 72 hours (Rescue Act, section 76). ## Basement round checklist The purpose of the round is to spot anomalies, not to carry out a condition survey. 1. Are there new damp patches or water on the walls or floor? 2. Is there a new or stronger smell in the space? 3. Is paint, coating or render peeling, and are there white deposits on the masonry? 4. Are there leaks or corrosion on the pipes, and is the insulation in good condition? 5. Are there water marks on the ceiling or at penetrations? 6. Is the ventilation working, or is the air constantly stuffy? 7. Are the access routes clear and the civil defence shelter in working order? 8. What do previously repaired spots look like? 9. Have the observations been recorded in the maintenance log (huoltokirja) with photos and dates? ## Find the cause before repairing The first repair idea for a damp wall is often to dry it out and paint it. If the source of the moisture remains, the new surface will soon be damaged. Recurring moisture, a strong smell, a clear leak or spreading marks should be assessed with a building expert. Sometimes a closer inspection is enough, sometimes a moisture investigation is needed, and sometimes the cause is found outside the building. A single measurement result should not be interpreted in isolation from the whole. Read more about [identifying moisture problems](https://huoneistokierros.fi/en/knowledge-base/moisture-problems-housing-company/). When observations, investigations and repairs are recorded, the next board will know what was observed in the basement, what was found to be the cause, what was repaired and how the success of the repair was monitored. This article provides general information and does not replace case-specific legal or technical advice. Free assessment ## Know what condition your housing company's apartments are in On a preventive apartment round we go through every apartment in a single visit at a fixed price and record our findings in an electronic report. The assessment is free of charge. [Book a free assessment](https://huoneistokierros.fi/en/contact/#kartoitus)[Get a price estimate](https://huoneistokierros.fi/en/pricing/#hinta-arvio) Preventive maintenance at a fixed price Every apartment on a single round. [Book a free assessment](https://huoneistokierros.fi/en/contact/#kartoitus) Read next ## Related articles - ![Hand holding a house-shaped keyring in front of an open door](https://huoneistokierros.fi/_astro/avain-ovi-auki.C8PnqZW6_Z1gOzVp.jpg) 24 August 2026 · 8 min read ### Monitoring the building's condition and reading the reports A condition assessment shows the building as it was on the day. What the law requires of monitoring, and how boards read reports and spot the gaps. - ![Stairwell with green walls](https://huoneistokierros.fi/_astro/porraskaytava-vihrea.yEkqQPNX_1GKniJ.jpg) 2 August 2026 · 6 min read ### The building walk-through: how the board inspects the building A building walk-through shows the board the building's real condition: what to check on the roof, in the basement, yard and stairwells, and how to record it. - ![Snowy courtyard of a block of flats](https://huoneistokierros.fi/_astro/sisapiha-talvi.DuGBVOJZ_Z2ljWMw.jpg) 10 September 2026 · 5 min read ### Housing company gutters: do they carry water away from the building? A blocked gutter or badly placed downpipe soaks the facade and plinth. How a housing company checks its gutters and rainwater drainage before winter. Free assessment ## Let's plan the right round for your housing company Call us or send a contact request. The assessment and advice are free of charge. We can visit the property if needed. [Send a contact request](https://huoneistokierros.fi/en/contact/#kartoitus)[Call +358 10 666 9988](tel:+358106669988)