External sealant replacement for windows, doors and expansion joints
External sealant is what keeps the joint between a frame and the surrounding masonry weather-tight. When it fails, rainwater and cold air find the smallest gaps and track inside.
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We remove failed sealant properly and replace it with the right external-grade materials, applied neatly and built to last.
When external resealing is needed
External sealant replacement is usually required when you notice:
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Sealant cracking, splitting or turning brittle
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Gaps opening between frame and brickwork
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Sealant pulling away from one side
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Water marks appearing after rainfall
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Draughts around the frame perimeter
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If you’re actively getting water in around a frame, start with the problem page: Water leaking around windows and doors.
Why perimeter joints fail over time
External joints fail for three main reasons:
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Weather exposure
UV, temperature changes and wind-driven rain gradually break down sealant.
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Movement between materials
Frames and masonry expand and move differently. Over time, stress builds at the joint.
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Poor original application
If the old sealant was applied over contamination, wasn’t tooled correctly, or didn’t have proper joint shape, it often fails early.
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When a joint fails, resealing over the top rarely lasts. The key is correct removal and preparation.
Our external sealing process
We carry out a proper replacement process:
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Remove failed sealant fully
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Clean and prepare the joint properly
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Check for gaps, voids and joint issues
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Apply suitable external-grade sealant
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Tool to a clean, weather-resistant profile
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Where a leak is linked to failed gasket compression rather than the external perimeter joint, we’ll advise gasket work instead: Window and door gasket replacement.
Why correct joint detailing matters
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A “neat bead” isn’t enough. Joint detail affects lifespan.
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If the bead is too thin, it splits.
If the bead is too thick or poorly shaped, it traps moisture or pulls away prematurely. -
Correct joint shape, adhesion and finishing are what make resealing durable.
We regularly carry out external resealing work across Leeds, Skipton and Harrogate, especially on exposed elevations where wind-driven rain is common.
Frequently asked questions
Will resealing stop the leak permanently?
If the perimeter seal is the cause, correct removal and replacement is a reliable long-term fix.
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Can you reseal over existing sealant?
We don’t recommend it. It usually fails early because adhesion and contamination issues remain.
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Is external resealing disruptive?
Most jobs are completed with minimal disruption and no internal mess.