Water leaking around your window or door frame
Rain getting in around a window or door frame is one of the most common problems we're called out to fix across Yorkshire. It usually starts small - a damp patch on the sill, a slightly wet edge to the plaster - and it rarely stays that way. Once water finds a route in, it will keep using it.
Before anything else, it's worth understanding what's actually letting the water through, because there are three quite different causes, and the fix for each one is different.
What is actually letting the water in?
External perimeter sealant failure
The most common cause. A bead of flexible sealant runs around the outside of the frame where it meets the brickwork or render. This sealant expands and contracts with temperature changes and movement in the building. Over time - typically 10 to 20 years, sometimes sooner on exposed elevations - it cracks, lifts away from the frame, or pulls back from the masonry. Once that seal is broken, even light rain can work its way in, and wind-driven rain will drive water directly through the gap.
Gasket failure
Inside the frame itself, a rubber or foam compression gasket runs around the glass unit and around the opening sashes. This is a different component to the external sealant - it sits within the frame, not around it. When the gasket perishes or loses its shape, gaps form that allow cold air and occasionally moisture through. Gasket failure tends to cause draughts even in dry weather, which is a useful diagnostic clue.
Failed mortar or cracked masonry around the frame
Less commonly, the issue isn't the frame at all - it's the masonry around it. If mortar joints close to a window have eroded or if there's a crack in the render or stonework nearby, water can track along the lintel or sill and appear to come from the frame. This is worth ruling out before any sealant work begins.
How do you tell which one is causing it?
A few simple observations help narrow this down before you call anyone.
If water only comes in during heavy or wind-driven rain, and the gap is visible on the outside of the frame, external sealant is almost certainly the cause.
If there are cold draughts when the window is shut, and the draughts persist in dry weather, the gasket is more likely to blame.
If dampness appears on the wall beside or below the window, not just at the frame edge, and the external sealant looks intact, check the mortar joints in the area and look for cracks in the surrounding masonry.
In practice, more than one issue can be present at the same time. We frequently find failed external sealant combined with eroded pointing nearby, particularly on older properties in areas like Bradford and Skipton where Victorian and Edwardian stone and brickwork is common.
What to do when you first notice it
Don't wait and monitor it. Water ingress around frames tends to worsen through autumn and winter, not improve, and Yorkshire's exposure to wind-driven rain from the southwest means that an exposed elevation can take a significant amount of water in a single storm.
A temporary measure - pressing sealant over the top of an old bead, or applying tape - is generally not worth the effort. Old sealant that has lifted or cracked needs to be removed completely before any new material will bond properly. Applying new sealant on top of failed sealant is one of the most common reasons these repairs fail again quickly.
What you should do: keep a record of when water appears and under what weather conditions. This helps us diagnose the cause more accurately when we attend.
How urgently does it need fixing?
More urgently than most people realise. Water tracking behind a window frame reaches timber subframes, insulation, and internal plaster. In a solid wall property, it can spread horizontally through the masonry. Mould can begin to establish within a few weeks of repeated saturation. Timber decay in older frames can become a much more expensive problem than the original sealant failure would have been.
The actual repair - removing old sealant and replacing it - is typically a short job. The damage caused by delaying it is not.
What a repair involves, step by step
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We inspect the frame and surrounding masonry externally and internally to establish what is causing the ingress.
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We remove all existing sealant around the affected frame. Old material is cut out fully - nothing is left that could compromise adhesion of the new joint.
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The substrate (brickwork, masonry or render) and the frame itself are cleaned and prepared.
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New sealant is applied in a single continuous bead, properly tooled to create a positive seal against both surfaces.
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If mortar joints nearby are contributing to the problem, we address these as part of the same visit where possible. See our Cement & Lime Repointing service for detail on how that works.
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Where the gasket is also failing, we carry out window and door gasket replacement as a separate but complementary repair.
Wind-driven rain on exposed Yorkshire elevations puts significant stress on external joints. A bead of sealant on a south or west facing elevation at altitude - common in properties around Ilkley, Otley and the Harrogate fringes - will degrade faster than one on a sheltered wall. We factor this into product choice and joint profile when doing the work.
Frequently asked questions
Q1. Can resealing stop the leak permanently? Yes - if failed perimeter sealant is the cause, correct removal and replacement is a reliable long-term fix. The key word is "correct": resealing over existing sealant rarely lasts. The old material must be fully removed, the joint cleaned and prepared, and the right external-grade sealant applied with the correct profile. When done properly, Northern Seal & Joint customers typically see no recurrence for many years. Q2. What actually causes water to leak around a window or door frame? The two most common causes are failed external sealant and a perished window gasket. External sealant breaks down through UV exposure, thermal movement and wind-driven rain - a common issue on exposed Yorkshire properties. Gaskets compress and harden over time, losing their seal. Both allow water to track inside, often appearing as a damp patch on the wall or sill below the frame. A proper inspection identifies which is responsible. Q3. How urgent is it - can I leave it for a few months? No, we'd advise against waiting. A small gap in sealant or a perished gasket lets in relatively little water at first, but repeated wetting spreads behind plaster, insulation and timber framing. What starts as a minor repair can quickly become a more costly job involving plastering, timber treatment or mould removal. Getting it fixed early is always cheaper and less disruptive than letting it deteriorate through another winter. Q4. Will my home insurance cover water ingress around windows? Possibly, depending on your policy. Most standard home insurance policies cover sudden water damage but exclude gradual deterioration - so a failed sealant that has been leaking slowly for some time is often treated as a maintenance issue rather than an insured event. It is worth checking your policy, but in most cases this is a repair you would arrange and pay for directly. We can provide a written report if your insurer requires evidence of the cause. Q5. Can I reseal a window myself, and is DIY a good idea? You can buy silicone sealant and apply it yourself, but DIY resealing is one of the most common reasons we're called out. The problem is usually preparation: sealant applied over old, contaminated or damp material fails within months. Getting a clean bond on a vertical exterior joint also requires the right technique. For a one-off window on a sheltered elevation it may be fine; for multiple windows or exposed positions, a professional job will last significantly longer. Q6. Does the time of year affect when leaks appear or when the repair should be done? Leaks often become noticeable in autumn and winter when prolonged rain and wind-driven moisture expose gaps that were dormant in dry weather. Repairs should ideally be done in dry conditions above 5°C to ensure proper sealant adhesion and cure time. Northern Seal & Joint works throughout the year in Yorkshire, scheduling jobs during suitable weather windows. If you notice a leak in winter, book an inspection so the repair can be planned for the first suitable day.
Recent local work -
Not sure if it's the frame or the wall?
If there's water ingress but you can't pin down the source, or if internal damp is appearing in more than one place, a Building Leak & Damp Inspection is the right starting point. We identify all contributing defects before any repair work is recommended.