Article 62(1) of the Building Law requires the owner or manager to carry out periodic inspections of a building: at least once a year, at least once every five years, and, for buildings with a built-up area above 2 000 m² and other structures with a roof area above 1 000 m², at least twice a year, by 31 May and by 30 November. Continuous monitoring does not replace these inspections. It fills the time between them by measuring what the inspection does not see: the effects of snow, wind and slow trends.
In short
- The periodic inspection under Article 62 is an obligation of the owner or manager. It is performed by a person with building qualifications in the relevant specialty, within the time limits set by the Act, and the report goes into the building log.
- The requirement for at least two inspections a year for large-area structures was introduced by the amendment of 10 May 2007, after the MTK hall disaster on the border of Chorzów and Katowice (28 January 2006, 65 fatalities).
- An inspection is a snapshot of the condition on one day. Snow, ice from frozen drains, wind gusts and overloads from suspended installations happen between snapshots.
- Continuous monitoring measures the effect of loading, strain and deflection of the girders, every 15 minutes by default, or more often, and sends an SMS when a threshold is exceeded. It does not relieve you of inspections; it gives the inspector a history instead of one look.
- For a regulatory inspection or an incident, keep the full set ready: reports in the building log, load documentation, a change register, a snow removal instruction and monitoring data with alarm and acknowledgement history.
What Article 62 of the Building Law says about periodic inspections
A periodic inspection is a check of the technical condition of a building by a person with the relevant qualifications, carried out within the time limits and scope set out in Article 62 of the Building Law and documented in a report. The Act does not use the word "review", only "inspection", but in the industry both terms are used interchangeably, and I use them that way in this text.
The table below is a paraphrase of Article 62(1) according to the legal status as of August 2026. The provision has been amended many times, so before making a decision, read the consolidated text in ISAP (link at the end).
| Basis | How often | What it covers |
|---|---|---|
| Article 62(1)(1) - annual inspection | at least once a year | elements of the building, structure and installations exposed to harmful atmospheric effects and destructive action of factors during use; environmental protection installations and equipment; gas installations and flues |
| point 2 - five-year inspection | at least once every 5 years | technical condition and suitability of the building for use, aesthetics of the building and its surroundings; inspection of electrical and lightning protection installations |
| point 3 - large-area structures (commonly: half-yearly inspection) | at least twice a year, by 31 May and by 30 November | scope as in point 1; buildings with a built-up area above 2 000 m² and other structures with a roof area above 1 000 m²; the inspector immediately notifies the building supervision authority in writing |
| point 4 - safe-use inspection | every time the circumstances referred to in Article 61(2) occur | verification of safe use after strong wind, heavy precipitation, lightning, shocks, landslides, fire, flood or ice phenomena |
| point 4a - inspection after a report | after a report of unjustified interference or breaches in the structure | check whether the structure meets the conditions of Article 5(2) (technical condition, use consistent with its intended purpose) |
Who may carry out the inspection is set out in Article 62(4)-(6): persons with building qualifications in the appropriate specialty; electrical, lightning protection and gas installations may also be inspected by persons qualified to supervise the operation of power and gas equipment, installations and networks, and flues by a master chimney sweep (smoke, gravity flue gas and ventilation flues) or a person with building qualifications. A manager without such qualifications may and should carry out their own site walks, but these do not replace the statutory inspection.
Three points from adjacent provisions are often missed in practice. First, Article 62(1a): during every inspection, compliance with the recommendations from the previous one is checked - the inspector reads the old report before writing the new one. Second, Article 70: defects and deficiencies that threaten safety must be removed during or immediately after the inspection, and the report with such a recommendation is sent to the building supervision authority. Third, Article 64: the reports are attached to the building log, kept in the digital c-KOB system - voluntary since 2023, mandatory for logs opened from 2024, and digital for all buildings from 1 January 2027. No entry means no proof that the inspection took place.
Article 61: the manager is responsible for safety between inspections
Article 61 of the Building Law imposes two obligations on the owner or manager. The first (point 1): maintain and use the structure in accordance with the principles set out in Article 5(2) - in proper technical condition, according to its intended use and environmental protection requirements. The second (point 2): ensure, with due diligence, the safe use of the structure in the event of external factors related to human activity or natural forces. The Act lists, by way of example, atmospheric discharges, seismic shocks, strong winds, heavy precipitation, landslides, ice phenomena on waters, fires and floods. Snow is not named there - it falls under "heavy precipitation" and that is how the provision is read in practice.
Pay attention to the structure of the second obligation. The Act does not provide a list of actions. It does not say "clear the roof at 20 cm" or "close the hall when the wind exceeds X m/s". It says: exercise due diligence. What counts as due diligence is assessed after the fact by the supervisory authority, an expert or a court. And it is assessed against what the manager knew or could have known at that moment.
Article 91a: liability is personal
Article 91a of the Building Law provides criminal liability for failing, contrary to Article 61, to maintain the structure in proper technical condition, to use it in accordance with its intended purpose and environmental protection requirements, or to ensure safe use. Penalty: a fine of not less than 100 daily rates, restriction of liberty, or imprisonment of up to one year. Separately, under Article 93(8), the Act treats the mere absence of the required inspection under Article 62 as an offence punishable by a fine; Article 93(9) concerns failures related to the building log.
A person is liable: the owner, the manager, or the person to whom the manager has formally assigned the duties. If you manage a portfolio of a dozen halls, that is the right reason to think about Article 62 not as a formality, but as personal risk. Management will ask whether monitoring is mandatory - it is not. It will also ask who is responsible if something happens between inspections - and here the answer is: you.
Where the twice-yearly inspection came from
On 28 January 2006, the roof of the hall of the International Katowice Fair in Chorzów, on the border with Katowice, collapsed during a pigeon exhibition. Sixty-five people died, more than 170 were injured - the largest building disaster in Polish history. Experts pointed to design and execution errors, the load from accumulated snow and ice, and previously damaged roof areas that had not been repaired. The findings on liability were determined in proceedings over many years, and I will not summarise them here.
From the manager's point of view, what matters is what happened to the regulations. The Act of 10 May 2007 amending the Building Law and certain other acts (Journal of Laws 2007 No. 99 item 665, in force from 20 June 2007) gave new wording to Article 61 - including point 2 on external factors - added Article 62(1)(3) with an inspection at least twice a year for large-area structures, and introduced Article 91a. The dates are not accidental: by 30 November the structure is to be inspected before the snow season, and by 31 May - after it - to see what winter has done to it. This was the legislature's response to a specific destruction mechanism: snow loading on roofs with a large surface area. For you, this means one thing: Articles 61, 62 and 91a should be read together, as one set of obligations and one responsibility.
Why twice a year is both a lot and not enough
It is a lot because it is real work. Each inspection under point 3 requires a person with qualifications, access to the roof and beneath the roof, a report, notification to the building supervision authority, an entry in the building log, a list of recommendations and the duty to implement them. A manager with a portfolio of a dozen halls has dozens of such inspections a year. For most phenomena that damage halls, that is enough: corrosion, leaks, loosening fasteners, damaged sheet metal flashings - these are slow processes that an inspection can see and describe.
It is not enough because what kills halls happens quickly and between dates. Snow, by definition, comes after 30 November and before 31 May - in the gap between inspections. Wind does too. Ice held back by frozen drains does too. Loading from installations suspended from girders over years of use - new ventilation, cable routes, photovoltaic systems on the roof - accumulates over a time span that no report covers, because the designer did not see that load and the inspector does not know the weight, only that something is hanging there.
A periodic inspection is a snapshot. It shows the condition of the structure on the day of inspection, to the extent that can be seen and measured manually. Between snapshots, the structure is blind. That sentence is the backbone of the entire guide to structural monitoring.
Continuous structural monitoring is the automatic measurement of selected quantities - strain, deflection, tilt, temperature - at fixed intervals, with warning and alarm thresholds and notifications, without human involvement in the reading. The difference between it and an inspection is best seen in the comparison.
| Periodic inspection (Article 62) | Continuous monitoring | |
|---|---|---|
| Who | a person with building qualifications | sensors and a platform; an engineer interprets |
| When | once, twice a year, after an event | every 15 minutes by default, or more often, all year round |
| What it sees | condition: corrosion, cracks, leaks, defects, geometry "by eye" and with measuring tools | change: increase in strain and deflection over time, response to snow, wind, temperature |
| What it does not see | what happened between visits | what is not under the sensor; it does not assess the condition of the element |
| Result | report, recommendations, entry in the building log | chart, OK / WARNING / ALARM status, SMS, history |
| Legal status | statutory obligation | voluntary measure of due diligence |
The time relationship can be calculated. Half a year is about 182 days; a reading at the default 15-minute interval means 96 measurements per day. Between two inspections there are therefore roughly 17 000 automatic readings. That order of magnitude is the whole difference between "event to knowledge" - not because monitoring is "better" than inspection, but because it is a different tool. Inspection assesses condition. Monitoring measures change. For you, this means both are needed and neither replaces the other.
Snow load: measurement instead of guessing
How much does snow on a roof weigh, and why nobody knows from the parking lot
Snow load in design is taken according to PN-EN 1991-1-3 (Eurocode 1, Part 1-3) with the national annex. Poland is divided into five zones; the characteristic ground snow load ranges from 0.7 kN/m² in zone 1, through 0.9 (zone 2, most of the country), 1.2 (zone 3) and 1.6 (zone 4), to at least 2.0 kN/m² in zone 5, with zones 1, 3 and 5 increasing with altitude above sea level. On the roof this is converted using shape, exposure and thermal coefficients; on the flat roof of a typical hall the load is lower than on the ground, but snow pockets form at parapets, skylights and roof steps, where it is locally much higher.
The manager's problem is simpler and worse at the same time: the density is unknown. Annex E to this standard gives an indicative unit weight of snow: about 1 kN/m³ for fresh snow, about 2 kN/m³ for settled snow, 2.5-3.5 kN/m³ for old snow and about 4 kN/m³ for wet snow. By way of illustration: 30 cm of fresh powder is about 0.3 kN/m²; the same 30 cm after thawing and a night frost, saturated with water, is about 1.2 kN/m² - the same as the characteristic ground load in zone 3. Measuring the depth with a rule therefore tells you little. Two roofs with "30 cm of snow" may be loaded four times differently, and the same roof on Monday and Wednesday as well.
There is also uneven distribution. Drifted snow accumulates near higher parts of the building and parapets. Meltwater held back by frozen drains turns into an ice sheet with density close to that of water. Partial snow removal while leaving the rest creates asymmetrical loading that the design may not have anticipated. A manager looking at the roof from the parking lot sees "white".
A sensor on a girder measures the effect, not the cause
Instead of estimating the cause - how much snow weighs - you can measure the effect: how the structure reacts. A roof girder under load deforms and deflects. Both phenomena can be measured continuously.
Strain is measured with a vibrating wire sensor mounted on the bottom or top chord of a truss girder or on the flange of a plate girder. The result is given in microstrain (µε); by way of illustration, for steel with a modulus of elasticity of about 210 GPa, an increase of 100 µε corresponds to an increase in stress of about 21 MPa. Vibrating wire sensors are used here not out of habit: they remain stable for more than 20 years, withstand hall conditions and provide a frequency signal that is difficult to disturb - I write about this separately in the text on why vibrating wire sensors are still the standard.
Deflection is measured with a displacement sensor or indirectly from tilts - inclinometers at the supports and at midspan allow the deflection line to be reconstructed. The national annex to PN-EN 1993-1-1 gives the recommended deflection limit for roof girders as L/250 of the span (for purlins, profiled sheets and slabs - other values apply); by way of illustration, for a girder with a 24 m span that is about 96 mm. The structural design should state what deflection and what strain correspond to the full design snow load - and that is the reference point for the thresholds.
A temperature sensor should always be added to strain sensors. A steel hall "breathes" daily: sunlight warms the top chord, night cools it, and the strain fluctuates with no snow at all. A strain chart against temperature makes it possible to distinguish this breathing from a permanent increase. Worried about false alarms? Without temperature, half of winter alarms will be alarms at sunrise - and that is why temperature is measured at each sensor, and thresholds are set with hysteresis.
Thresholds: the designer's decision, not the platform supplier's
A warning threshold (WARNING) is the value at which the manager should start acting - check the roof, look at the forecast, start snow removal. An alarm threshold (ALARM) is the value at which discussion stops and people are removed from the area under the girder. Let us assume, for illustration, that the designer states that full design snow load causes an increase in strain of 400 µε in the bottom chord of the girder compared with the roof without snow. WARNING at half that value and ALARM at about three quarters is one possible arrangement - but that decision belongs to the structural engineer who knows the structure, taking into account reserves, the condition of the elements and the consequences. How to set thresholds so that an alarm means something is described in the text on warning and alarm thresholds.
This leads to a condition that is often forgotten: the zero reading. Strain from a vibrating wire sensor is relative - it measures the increase from the state in which zero was defined. Zero should be set in a known condition of the structure (roof without snow, known temperature) and documented, otherwise the thresholds hang in the air.
What to do when the SMS arrives
Thresholds are useless without a procedure. It should be written before winter and known to the people who receive notifications: who answers the SMS at 2 a.m., who confirms receipt, who has authority to order snow removal, who closes the zone. Snow removal itself is a load and a risk - people on the roof, snow being thrown down, uneven unloading - so the snow removal instruction should define the order of areas and the principle of symmetry. The sensors then show whether snow removal is working: the strain in the girder chords should return toward zero, area by area. What this means for you: snow stops being a guess from the parking lot and becomes a number on the girder, linked to a decision.
Monitoring does not release you from inspections, but it changes their quality
Article 62 requires an inspection by a person with qualifications, within the prescribed times, with a report and, for large-area structures, written notification to the building supervision authority. No monitoring fulfils or replaces this obligation. A manager who "replaces" inspection with monitoring still has no inspection - and that is an offence under Article 93(8), and in the event of an incident, an argument against them.
Monitoring supports inspection in three ways.
First, the inspector gets a history instead of one glance. Half a year of strain, deflection and temperature, with marked snow episodes and alarms, tells them which girders behaved differently from the adjacent ones, whether strains returned to zero after winter, or whether a permanent increase remained. The inspection becomes targeted: not "walk around the hall", but "start with the axes where warnings were triggered in winter".
Second, post-inspection recommendations can be verified numerically. If the report says "observe the deflection of the girder in axis X", then between inspections someone actually observes it instead of waiting until the next one - and at the next inspection, in accordance with Article 62(1a), it is possible to show what that observation led to.
Third, the due diligence under Article 61(2) stops being a declaration. The provision is evaluative, and it is assessed after the fact. A manager who has measurements of load effects, thresholds agreed with the structural engineer, a written procedure and a history of using it is in a different position from someone who "looked at the roof and it seemed fine". That is an engineering assessment, not a legal interpretation - but in proceedings after incidents, the same questions are always asked: what did you know, when did you know it, and what did you do about it.
How to calculate that difference in time - from event to decision - without marketing multipliers is shown in the text on what "100x faster" really means.
What to keep ready for an inspection or incident
After an incident - and also during a routine inspection by the building supervision authority - documents are needed quickly, in full, and in a form that leaves no doubt as to when they were created. The list below is a checklist, not a legal interpretation.
| What | Why | What to watch out for |
|---|---|---|
| Building log with Article 62 inspection reports | proof that inspections were carried out, on time, with recommendations | completeness of entries, signatures of qualified persons, trace of written notification to the authority for inspections under point 3 |
| Design and as-built documentation, including load assumptions | shows which snow zone and what suspended loads the design used | discrepancies between design and actual condition: new installations, photovoltaics, cranes, mezzanines |
| Register of changes in the structure (suspensions, alterations, changes of use) | shows whether loads increased compared with the design | no register means no one calculated the increase |
| User and snow removal instruction + snow removal log | proof of the procedure and its application | sequence of areas, principle of symmetry, who decides, dates and contractors |
| Evidence of implementation of post-inspection recommendations (Article 62(1a), Article 70) | closes the loop between inspections | a recommendation without proof of execution is an argument against the manager |
| Monitoring data: zero reading, certificates and calibrations of sensors, raw data, export | answer to the question "what did you know and when" with quarter-hour precision | zero must be documented; raw data, not a polished chart |
| Alarm history with acknowledgements and configuration change log | trace of human decisions: who received the SMS, who took over, who muted the alarm and for how long | gaps in data (NO_DATA) are also information - and they also must be explained |
| Correspondence with the building supervision authority | continuity of the process | date of receipt and responses |
Monitoring data work both ways. A history showing that an alarm came at 2 a.m. and the first reaction happened three days later is evidence - just not in the manager's favour. That is why the procedure and assignment of roles are as important as the sensors. I describe in detail what a measurement record must contain for an expert to accept it in the text on monitoring data as evidence in a dispute. What this means for you: the full set from the table can be gathered into one binder and one folder - and it is worth doing before winter, not after a call from the authority.
What this looks like in Inclify
On a steel hall, the typical setup includes vibrating wire strain sensors on the chords of selected girders, on the most heavily loaded ones and those near snow pockets, temperature sensors next to each of them, and where needed, displacement sensors or inclinometers for deflections. The logger sends readings to the platform every 15 minutes by default, or more often; each channel has its own WARNING and ALARM thresholds with hysteresis, set with the structural engineer, and the OK / WARNING / ALARM / NO_DATA status is visible on the object dashboard. Exceeding a threshold sends an SMS and an e-mail to project users according to their settings; the panel shows who acknowledged and took over the case, and the alarm can be muted for a specified period, so it does not wake everyone every 15 minutes during snow removal, but never indefinitely.
A multi-axis chart shows strain against temperature, which makes it possible to distinguish daily breathing from the increase under snow. Alongside sensor data, an IMGW widget - weather and warnings - can be displayed as context for interpretation, not as the source of the alarm; the alarm always comes from the measurement on the structure. The zero reading is saved in the platform as a reference, and engineering reports include, among other things, temperature compensation, data SLA (completeness and gaps) and threshold tuning with proposals that can be applied. The alarm history with acknowledgements and mutes and the configuration change log remain in the platform; raw frames from the devices are in the communication log for the configured period (default 7 days). Measurement data can be exported to CSV, and multiple halls are handled in one panel as a portfolio, with roles and permissions for the team.
If the hall already has sensors and a logger, connecting it to the platform takes a few days. A turnkey deployment, including sensor selection and installation, takes from several to several dozen weeks - so if you want data for the first snowfall and for the inspection by 30 November, the decision must be made in summer or early autumn. Details of use in buildings and halls: /solutions/buildings.
FAQ
Does structural monitoring exempt you from the periodic inspection under Article 62?
No. Article 62 of the Building Law requires an inspection by a person with building qualifications, within specified time limits, with a report and, for large-area structures, written notification to the building supervision authority. No monitoring fulfils this obligation. Monitoring supports the inspection: it gives the inspector a history of measurements between visits and allows the manager to react to snow or wind before the deadline arrives.
Which structures are inspected twice a year?
Under Article 62(1)(3) of the Building Law, buildings with a built-up area exceeding 2 000 m² and other structures with a roof area exceeding 1 000 m² are subject to inspection at least twice a year - by 31 May and by 30 November. In practice, this includes production halls, warehouses, shopping centres, stadiums and event venues. The scope matches the annual inspection under point 1.
Who may carry out a periodic inspection of a structure?
Inspections under Article 62 are carried out by persons with building qualifications in the relevant specialty (Article 62(4)). Electrical, lightning protection and gas installations may also be inspected by persons qualified to supervise the operation of power and gas equipment, installations and networks, and flues by a master chimney sweep or a person with building qualifications (subsections 5-6). The owner or manager is responsible for ensuring that the inspection takes place.
Do the regulations require monitoring snow load on a hall?
The Building Law does not require installation of monitoring. It does require, under Article 61(2), that the safe use of the structure be ensured with due diligence in the event of external factors, including heavy precipitation (and therefore snow as well). How to provide that diligence is chosen by the manager: site walks, manual measurements, a snow removal procedure, or continuous monitoring. Monitoring is one of the measures, and it documents well that diligence was real.
What should be measured in a steel hall to know about roof overload?
The strain in the girder chords with vibrating wire sensors (µε), the deflection of girders with displacement sensors or indirectly from inclinometers, and always the temperature near the sensors, so that daily thermal changes can be separated from the increase under load. Thresholds should be related to the design values - how much strain and deflection correspond to the full design snow load - and set with the structural engineer, not the platform supplier.
What is the penalty for missing a periodic inspection?
Failure to carry out a required periodic inspection is an offence punishable by a fine under Article 93(8) of the Building Law, and failure to ensure safe use or to maintain the structure in proper technical condition may be an offence under Article 91a, punishable by a fine of not less than 100 daily rates, restriction of liberty, or imprisonment of up to one year. Liability rests with the owner or manager. This text is not legal advice; in a specific case, consult a lawyer.
Sources and further reading
- Act of 7 July 1994 - Building Law, consolidated text in ISAP: https://isap.sejm.gov.pl/isap.nsf/DocDetails.xsp?id=WDU19940890414 (Articles 61, 62, 64, 70, 91a, 93).
- Act of 10 May 2007 amending the Act - Building Law and certain other acts (Journal of Laws 2007 No. 99 item 665): https://isap.sejm.gov.pl/isap.nsf/DocDetails.xsp?id=WDU20070990665
- PN-EN 1991-1-3 Eurocode 1: Actions on structures - Part 1-3: Snow loads, together with the national annex (PKN, sklep.pkn.pl).
- PN-EN 1993-1-1 Eurocode 3: Design of steel structures - Part 1-1, together with the national annex (deflection limits) (PKN, sklep.pkn.pl).
- Digital building log c-KOB - information from the Chief Building Supervision Office (gov.pl/web/gunb).
- IMGW-PIB meteorological warnings (imgw.pl).
- Other posts in the series: guide to structural monitoring, warning and alarm thresholds, vibrating wire sensors, monitoring data as evidence, "100x faster" - how to calculate it.
What next
If you manage a hall, warehouse or stadium and want to know what happens to the girders between the November and May inspections, start with one structure - the one with the largest roof or the worst snow removal history. A pilot can be launched on sensors you already have, or with selection and installation; we will show you what it looks like on a structure similar to yours. Do it before the snow season, so that you already have the first data for the inspection by 30 November. We respond within 24 hours: book a call.