Humidity and Mould on Windows in Wrocław – Why Lower Silesia is Different and What to Do
Wrocław and Lower Silesia have Poland's highest rainfall and relative humidity. The Odra valley microclimate means windows here condense more intensively than anywhere else in the country — and where condensation persists, mould follows if the window is not properly sealed.
Wrocław lies in the Odra valley — one of Poland's most humid areas, with annual precipitation of 600–650 mm and relative humidity regularly exceeding 80–85% in autumn. Atlantic fronts arrive from the west unimpeded, bringing prolonged rain in autumn, spring and late summer. For window owners in Krzyki, Fabryczna, Stare Miasto and Psie Pole, this means a specific challenge: more condensation, more mould risk, and faster external seal degradation.
Why Condensation Is Worse Here
Condensation forms when glass surface temperature drops below the dew point of indoor air. In dry Poznań (winter humidity ~60–65%) this threshold is rarely crossed on modern double glazing. In Wrocław, where outdoor humidity regularly reaches 85–100% in fog and rain, indoor humidity rises quickly through any infiltration path — causing heavy condensation on lower glass edges and in frame corners. Persistent condensation leads to mould growth within 2–4 weeks if water cannot evaporate.
Three Root Causes of Mould at Windows
Thermal bridges in the profile: frame corners and profile junctions are thermally weaker — they run colder and condense first. Sealing with interior-side vapour-barrier silicone eliminates the permanent condensation zone. Missing vapour barrier at installation: pre-2005 windows were often installed with just expanding foam, no sealing tapes. Without an interior vapour barrier, warm humid indoor air migrates behind the frame and condenses in the insulation layer — causing mould not just on the sill but on the wall beside the window. Repair: remove interior trim, inspect foam, seal with vapour-barrier tape. Window sealing without full frame removal. Worn seals and draughty sashes: Wrocław's air is exceptionally humid, so any infiltration path imports moisture directly. Seal replacement eliminates the main infiltration route.
The 1997 Flood Legacy
The 1997 Odra flood inundated large parts of Wrocław. Buildings in Kozanów, Popowice and riverside areas of Stare Miasto can still have residual capillary moisture rising through walls toward window openings. Symptom: a dark damp patch on the wall below the window, or white efflorescence on interior plaster near the frame. Sealing the window alone is insufficient here — the external sill connection must also be checked and resealed.
Seasonal Pattern
Autumn (September–November) is the worst period — fog season, high humidity, cooling glass. Every seal failure and missing vapour barrier becomes visible. Ideal time for inspection and repair. Spring (March–April) — check for frost damage to seals, clear weep holes, inspect external sills after the wet winter. Consider fitting a filtered trickle vent before summer humidity increases further.
We serve Wrocław and Lower Silesia – same-day technician visits available. Book a window service in Wrocław if you see condensation, mould, or damp patches near your windows.
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Frequently Asked Questions
Everything you need to know about our window and door repair services
Yes, the initial diagnostics and our technician's visit to assess the work are completely free. No hidden costs and no obligations. If you decide to proceed with the service, the technician will provide a clear quote on site, explain all the details, and if needed – can start work immediately and complete the repair during the same visit.
Absolutely! We provide a warranty for both the services performed and the materials used – in accordance with applicable regulations.
We cover all of Poland, with a particular focus on major metropolitan areas: Warsaw and surroundings, Kraków and Małopolska, Łódź area, Poznań and surroundings, Katowice and all of Silesia (Sosnowiec, Gliwice, Chorzów, Bytom, Zabrze, Tychy and 30+ cities). Call us – we'll call back within 15 minutes to arrange a visit.
The price depends on the type of window, the nature of the issue, and the materials needed. Upon arrival, the technician will provide an exact quote on site with no hidden fees, and you decide whether you want to proceed with the work.
Booking a free diagnostics is very simple. Just call our contact number or fill in the registration form – either way it only takes a few minutes.
In most cases, repair is sufficient: replacing seals or hardware, sealing, adjustment, cleaning and lubricating the mechanisms. This is a much cheaper solution than installing new windows.
Repair is cheaper because you don't need to buy a new window, remove the old one, dispose of it, or carry out finishing work after installing a new unit. Repair saves both time and money, being a significantly more cost-effective solution.
We service windows from all major manufacturers, including: Rehau, Veka, KBE, Schuco, Salamander, Aluplast and many others. Our technicians undergo training on the specific mechanisms of each manufacturer.
Yes, we accept all major payment cards, bank transfers and cash. Payment is made after the work is completed.
Yes, we provide services all year round. During winter, we carry out window servicing using special methods to avoid cooling down the rooms and ensure maximum comfort.
Balcony door adjustment for PVC or aluminium doors starts from 80 zł. It includes precise 3D adjustment of hinges and fittings, eliminating sagging, draughts and closing issues. Free on-site diagnostics – the technician will quote on arrival.
Yes. We specialise in sliding and HST terrace door service for all major systems: Schüco ASS 70/77, Aluprof MB-77 HS, Aliplast Imperial. We replace load rollers, repair tracks, adjust closing pressure and service drive mechanisms. From 150 zł.
A window ventilator (trickle vent) is a ventilation device fitted in or above a window frame, providing a constant supply of fresh air without opening the window. Since 2021 (Polish building regulations WT 2021), ventilators are mandatory in new buildings. We install pressure-controlled, humidity-sensitive and acoustic ventilators – from 80 zł each.
After your enquiry we call back within 15 minutes and agree a time. In most cities (Warsaw, Katowice, Łódź, Poznań, Kraków) a technician arrives the same or next working day. For urgent cases such as a fallen hinge or jammed door, we aim to arrive within a few hours.