Water is coming through my windows

The entry point for water leaks can be very tricky to identify and where they appear to be is not necessarily where they originate from. Before blaming the windows, is good to check these things first.

Is water really coming through your windows or is it coming from somewhere else?

The actual entry point for water leaks can be very tricky to identify and where they appear to be is not necessarily where they originate from. Water has the ability to enter through very small cracks in paint and other materials and it can track a long way.

There is no doubt some compromised windows (e.g. rotted out) can contribute to water ingress, and our experience shows that old wooden windows tend to cop the blame for being the weak point for water ingress, particularly during a storm event.

This certainly can occur but after old windows have been made to operate properly and draught sealed, our experience shows that the water is generally entering from elsewhere in the building and may be exiting internally via a window.

The window cops the blame when in fact there are other factors at play.

Before blaming the windows themselves look into the following:

  1. Are there external wall vents outside and do they have covers? Wall vents, particularly those without covers, can allow wind driven rain to enter the wall cavity and then water tracks down to any horizontal sections e.g. window frame and exists via the internal side of the window.

Above are vents with covers over them to reduce windblown water entering the wall cavity:

  1. Is the water that is entering clean or dirty looking? Does it leave a brown or dirty stain after it dries? Dirty water indicates the water could be entering via the wall cavity or roof above washing down dirt from the cavity/roof.

Above images show Dirty water indicating water is entering via the walls/roof:

  1. Is the roof sealed and in good condition? If there is a roof membrane, has it ruptured anywhere and accumulated water under it. If water enters the roof it can exit below at window frames.
  2. For brick buildings, is the pointing in good condition around the frame of the window where the frames meet the wall? If this area is not sealed or the storm beads have gaps, windblown rain can enter the wall cavity.

Above gaps can be shown between the brick work and frame which let water in:

  1. Are flashings installed and if so are they in good condition?
  2. Are the gutters and overflows clean and unobstructed? Do they have the capacity to cater for predicted storm events?
  3. Are pipes and gutters functioning properly during heavy rain events? Is there any evidence of water leaking down the outside of walls or into the wall cavity during a rain event?

So if you happen to have water ingress after work has been undertaken on your wooden windows, investigate all the possible factors discussed above. Our sealing system is not designed to stop rain, it is designed to stop draughts and if it does that it will diminish the chances of rain entering gaps in wooden windows and doors.

After we make your windows open and close properly Sealasash seals have multiple benefits to stop wind and water entering through the sliding and opening surfaces.

  • Brush seals for sliding surfaces have silicone on the brush pile to protect and repel water.
  • A central twin wiper fin sits above the double row of brushes to create a physical barrier against wind and water.
  • Water-proof compression seals with extremely good coverage are used on closing surfaces like casement windows.
  • Seals, even double rows, are put into all the gaps to maximise the impact you need.

 So please try to keep in mind two things

  1. Water is a mysterious substance, where it comes out from is not necessarily where it maybe entering the building
  2. Draught sealing is not weatherproofing.

If you would like to talk to a timber window expert who understands all your options, and who will listen to your priorities, then please don’t hesitate to contact us.

Looking for double glazing for your sash windows or wooden windows?

Sealasash can double glaze your old timber, wooden and sash windows with new high-performance glass.  We also upgrade windows to include draught and acoustic seals that further improve the comfort and energy efficiency of your windows. 

Learn more about Sealasash:


Vacuum Insulated Double Glazing

Our ultra-high performance double glazing fits perfectly within your existing timber work, eliminating any bulky or expensive modifications.


Fix Those Annoying Rattles

With our draught and acoustic seals you’ll achieve amazing new comfort levels by reducing infiltration of outside air, noise and dust without the annoying rattles.

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Using traditional craftsmanship and modern materials, we’ll restore your windows and make them better than new.  This includes high-performance double glazing and draught seals that will dramatically improve the comfort and energy efficiency of old timber, wooden and sash windows.