Do you notice moisture around your skylight? We at Ultrices Leak Detection are quick to detect skylight leaks without demolition and with clear steps to repair.
We check every junction of the skylight: frame, glazing beads, rubbers, sealant joints, lead flashing, waterproof collar, connection to roof tiles or bitumen underlayment, and the drain to the gutter.
With thermography, smoke test, dye endoscopy, and moisture measurement, we pinpoint the exact source, and you receive a clear report and advice. Don't hesitate and check our Google reviews: 5 out of 5 at experiences with detecting skylight leaks.
Table of contents
Detecting a skylight leak: what it is and why it goes wrong
Detecting roof window leaks means determining, in a targeted and non-destructive manner, where water is entering around your roof window and why. Water seeks the path of least resistance and follows gaps around the frame, flashing, and roofing. Capillary action, wind-driven rain, negative pressure, and condensation all play a role. For systems from Velux, Fakro, and Roto, the correct combination of frame, glazing, waterproof membrane, and matching flashing is crucial. If foils, lead flashing, or connection profiles are not installed according to the installation manual, you will experience infiltration that you often only notice when it is too late. We combine building physics with practical experience to detect roof window leaks with maximum certainty and minimal inconvenience.
Signs of a leaking skylight that you must not ignore
- Wet spots and rings: damp spots on plasterboard, trim, or ceiling directly below or diagonally next to the skylight, often after rain
- Mold and musty smell: black speckles on sealant edges and reveals due to prolonged moisture exposure
- Droplets or condensation: visible moisture between the glazing bead and the glazing or at the bottom of the frame due to a thermal bridge and poor airtightness
- Peeling paint or swelling wood: deterioration of wooden window frame or trim caused by rising capillary water
Our proven method for detecting skylight leaks
We combine geometry, visual inspection, and controlled simulations. This way, you get hard data and a clear expert report that insurers accept, rather than guesswork. We detect skylight leaks step-by-step and without any demolition or breaking.
- Intake and analysis: we discuss complaints, year of manufacture, brand and type of skylight, and conduct a risk analysis based on weather data and usage
- Visual inspection: we inspect the flashing, waterproof membrane, lead flashing, battens, and connections on the inside and outside
- Moisture measurement: with Trotec and Protimeter equipment, we measure material moisture, relative humidity, and surface temperature
- Thermography: a FLIR infrared camera reveals thermal bridges, wet insulation, and hidden leak paths around the skylight
- Targeted simulation: smoke test, tracer gas or controlled water test to confirm the exact infiltration site
- Report and advice: within three days you will receive a complete expert report with photos, measurements, and repair advice
Leak detection process request
Techniques and equipment for leak detection in skylights
- Thermographic researchInfrared images make temperature differences visible, so that damp zones and thermal bridges around the window frame stand out immediately.
- Tracer gas detection: a safe hydrogen-nitrogen mixture escapes through micro-cracks and is precisely located with a gas detector
- Smoke and pressure proof: controlled pressure build-up and smoke show air leaks and reverse flow under wind load
- Endoscopy and fluid logging: using an endoscope and data logger, we inspect the cavity, insulation, and underlayment over multiple rainy periods
If you want to understand in more detail how broadly roof leaks can be investigated and how this relates to your situation regarding the skylight, read on about professional roof leak detection or discover our approach for Leak detection without demolition or breaking.
Types of roof windows and typical sources of leaks
- Tilt windows: leakage at the pivot point or sill if rubber seals age or the flashing does not lie flush on the tiles
- Extension or tilt mechanism: water through the top frame due to insufficient expansion space or incorrectly installed water-repellent membrane
- Electrically operated skylights: infiltration via cable entry or sensor module if the collar and sealant edges are not properly sealed
- Combination frameworks and linkages: leaking seam between two frames due to tension cracks or insufficient overlap of the coupling pack
Common installation and maintenance mistakes regarding skylights
- Incorrect gutter type: universal flashing on unsuitable roof tiles or slates causing water to strike against the upstand and infiltrate
- Interruption of water-repellent membrane: missing flashing or non-continuously applied vapor barrier causes leak paths behind the trim
- Wearing rubbers and sealant joints: aged glazing rubber or sealant cracks open and allows water to run in along the glazing bead
- Wood rot and deformation: warped frame emphasizes rubbers and creates gaps that let water through during driving rain
Why Ultrices leak detection is the safest choice
We are Ultrices Leak Detection, and we help you locate skylight leaks without unnecessary demolition work. Nationwide coverage, on-site within an hour in emergencies, and always with VCA VOL and NEN 3140 certified specialists. We work according to guidelines from manufacturers such as Velux, Roto, and Fakro and use professional instruments from FLIR and Trotec. Our success rate is ninety-nine percent, our report is accepted by insurers, and you receive a guarantee on coverage and repair advice. No solution, no payment, and completely risk-free for both private and business clients. For immediate help or advice, call or WhatsApp 085 2505 217 or email info@Ultriceslekdetectie.nl. Do you want quick clarity and certainty regarding the costs, Receive a quote for leak detection at your skylight within 24 hours.If the leak extends beyond just the window or you suspect the surrounding surface, then it is wise to also read about Professionally detect roof leaks so that you include the entire roof surface in the diagnosis.
Practical example
In a terraced house in Utrecht with a Velux pivot window, we observed rings next to the frame after a westerly wind. Thermography revealed a cold streak along the flashing. Using a smoke test and a targeted water test, we confirmed a capillary leak caused by an incorrectly chosen flashing on a flat tile. The repair recommendation involved the correct flashing, a new lead flashing, and the continuous attachment of the waterproof membrane to the frame. The client received an expert report within three days, and the insurer approved the repair.
Frequently asked questions
How do you know if your skylight is leaking or if it is condensation?
Condensation often forms evenly on the glass or on the interior aluminium, especially on cold nights with little ventilation. It dries quickly if you ventilate or heat. An actual leak leaves traces such as brown circles in plaster, soft spots in trim, mould around the frame, and damp patches that worsen in rain and wind.
We measure the dew point, record temperature and relative humidity, and use thermography to detect thermal bridges and wet insulation. With endoscopy, we inspect the flashing, lead flashing, and side connections under the roof tiles. You will receive clear advice with photographic evidence. If you already have ceiling damage and want to properly substantiate this for your insurer, please take a look. our approach to ceiling leakage with insurance report.
What is the fastest way to detect a skylight leak without demolition work?
We combine non-destructive techniques so you don't have to do any hacking or breaking. Think of infrared thermography for hidden moisture trails, a smoke test to find cracks, ultrasound to trace leaking seals, a dye and spray test for controlled rain simulation, and endoscopy under the roof tiles at the flashing and side connections.
With this mix, we find the source in a single visit with a 99 percent success rate. We operate nationwide, are on-site within 1 hour in emergencies, and work 24 hours a day, 7 days a week. VCA VOL and NEN 3140 certified, professional equipment, and no cure, no pay. If you want to see how we apply this outdoors as well, take a look. Leak detection on facades without hacking.
Why does my Velux or Fakro roof window only leak during heavy rain and what is the solution?
Wind pressure plays a major role in driving rain. Common causes include an incorrect type of flashing relative to the roof profile (e.g., EDW or EDL), insufficient overlap with the tiles, a deformed lead flashing, aged rubbers and sealing strips, clogged drains around the window frame, or a defect in the vapor barrier foil allowing water to penetrate via capillary action.
We conduct targeted testing using a spray test and smoke test along the top connection, side connection profiles, and water barrier channels. This allows us to determine whether cleaning, replacing rubber seals, repairing the lead flashing, or installing the correct flashing is necessary. You will receive a comprehensive expert report with photos within 3 days that insurers accept. If you also recognize rainwater penetration elsewhere, read on. What to do if your facade only leaks when it rains.
How much does it cost to detect a skylight leak, including an insurance report, and can you come today?
The price depends on accessibility, roof type, and required measurement methods. You will receive a free quote within 24 hours, and we will deliver a comprehensive expert report with measurement data and photos within 3 days. We work with insurers and assist with the claim. Coverage depends on your policy; always check this with your insurance company.
In emergencies, we are usually on-site within 1 hour, deployable nationwide, and available 24 hours a day, 7 days a week. No demolition or breaking work, professional detection equipment, for residential and business use. Five out of five Google stars, over 15 years of experience, and no cure, no pay. This way, you remain 100 percent risk-free with Ultrices leak detection.