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PVC Window streaks after rain. Can it be solved

  • 11-11-2025 02:16PM
    #1
    dnme
    Registered Users, Registered Users 2 Posts: 3,453 ✭✭✭


    I have a relatively new picture window installed about a year ago. I notice that whenever it rains, I'm left with some rain streaks down the center of the window. These then dry out to watermark stains that have to be cleaned. None of my other windows do this. Bear in mind, the window is working perfectly. There are no leaks etc. I have had a look outside at the upper reveal when it's raining and I cannot see any obvious problems. I'm just wondering if anyone else has experienced this? Is it solvable? Many thanks. See attached images.

    PXL_20251111_133817775.jpg

    PXL_20251111_133847665.jpg

    PXL_20251111_135846714.jpg
    Tagged:


Comments

  • #2
    bfclancy2
    Registered Users, Registered Users 2 Posts: 242 ✭✭bfclancy2


    some bigger issue going on there by the look of it, why would water be streaming down the window from rain hitting it, doesn't make sense



  • #3
    brokenbad
    Registered Users, Registered Users 2 Posts: 2,324 ✭✭✭brokenbad


    Looks like the seal between the frame and glass is holding water for some reason and then it's dribbling down the glass when it overflows onto the pane. Get the window installer back to fix this issue.



  • #4
    10-10-20
    Registered Users, Registered Users 2, Paid Member Posts: 9,734 ✭✭✭10-10-20


    It might be an insufficient overhang on the top reveal, or the reveal is flush with the render and not capable of shedding the down-wash. A better photo showing the wall, reveal and window would be required.



  • #5
    dnme
    Registered Users, Registered Users 2 Posts: 3,453 ✭✭✭dnme


    https://www.boards.ie/discussion/comment/123980335#Comment_123980335

    More photos attached.

    PXL_20251111_161225067.jpg PXL_20251111_161232731.jpg


  • #6
    10-10-20
    Registered Users, Registered Users 2, Paid Member Posts: 9,734 ✭✭✭10-10-20


    Two questions as I can't tell from here:

    Is the water tracking from the render and back into the window or is the water coming from between the reveal and the window frame?

    Who fitted the reveal?

    It looks to me to be a pretty flush reveal anyway...



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  • #7
    dnme
    Registered Users, Registered Users 2 Posts: 3,453 ✭✭✭dnme


    https://www.boards.ie/discussion/comment/123980512#Comment_123980512

    It's hard to know. When I stand out in the rain and look at it, it all seems perfectly normal. I can't really follow any water path. The streaks run down the outside of the glass. In the very last photo above, you can see the marks left. They are getting harder to clean. I cleaned the window again this afternoon and even tried a cloth with a little IPA on the streaks, but to no avail. Whats going on here? Has anyone any experience with this issue?



  • #8
    10-10-20
    Registered Users, Registered Users 2, Paid Member Posts: 9,734 ✭✭✭10-10-20


    It's one of two things:

    Either the reveal is not shedding the run-off water - normally they are angled slightly downwards so the water drips off and doesn't track back onto the window.
    Or - the water is penetrating the exposed wall and accumulating over the reveal and then running down the window.

    If it's the latter then it's very concerning - hence why I asked who installed the reveal. Both methods would pickup some dirt or salts and then deposit it on the windows glass as it drys. If it's the former then the reveal could have a small bead of silicon added to the underside lip of the reveal to match the colour, and this would force the water to drip off and avoid the window.

    Is the water coming down over the full length of the window or only around the middle of the window?



  • #9
    dnme
    Registered Users, Registered Users 2 Posts: 3,453 ✭✭✭dnme


    https://www.boards.ie/discussion/comment/123980572#Comment_123980572

    There are 4 or 5 streaks all in or around the center of the window. If you look at the very last image above, it shows 3 streaks, there are in the middle of the window. The outer edges are perfect, the streaks are just down around the middle.



  • #10
    10-10-20
    Registered Users, Registered Users 2, Paid Member Posts: 9,734 ✭✭✭10-10-20


    https://www.boards.ie/discussion/comment/123980597#Comment_123980597

    On that basis I'd suspect that it could be leaking through the lintel/reveal. But you haven't answered my other question though…



  • #11
    dnme
    Registered Users, Registered Users 2 Posts: 3,453 ✭✭✭dnme


    https://www.boards.ie/discussion/comment/123980644#Comment_123980644

    Is the other question "Who fitted the reveal?"

    If so, I'd prefer not to mention anyone's names. But I can tell you, I renovated the place last year. This picture window is new. It required an Engineer, structural steel / lintel into foundation. The entire reveal is new and was built by the builder. Does that help?



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  • #12
    10-10-20
    Registered Users, Registered Users 2, Paid Member Posts: 9,734 ✭✭✭10-10-20


    Builder then and not the window installer. So you need to work out whether the water is coming around the front of the reveal/lintel (ie tracking around the outside), or is it coming down the wall and either penetrating through the wall or along the upper side of the lintel. Only a visual inspection of the window at the time of the event will tell you that.

    If it's the latter then you need to take action before the reveal fails. If it's the former then you can relax and just have somebody run a silicon bead as I described.



  • #13
    dnme
    Registered Users, Registered Users 2 Posts: 3,453 ✭✭✭dnme


    Many thanks for all your helpful input 10-10-20. The builder in question left me enough problems that I've decided to ask another builder to come onsite and have a look around. This will be one to add to the list.



  • #14
    Cluedo Monopoly
    Registered Users, Registered Users 2, Paid Member Posts: 12,942 ✭✭✭✭Cluedo Monopoly


    You have a leak behind the wall or at the top of the window. Look for cracks in the plaster. Some sealant on top of the reveal could fix it. Does the stain left behind after the rain look white? Kinda limey?

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  • #15
    dnme
    Registered Users, Registered Users 2 Posts: 3,453 ✭✭✭dnme


    https://www.boards.ie/discussion/comment/123980807#Comment_123980807

    I have looked closely inside and out, while both raining and dry. I have even used a moisture meter which reveals nothing abnormal. A leak is very unlikely.



  • #16
    TitianGerm
    Registered Users, Registered Users 2 Posts: 29,945 ✭✭✭✭TitianGerm


    12438.png

    Is it just the photo or does the rubber seal look to be folded back on itself here?



  • #17
    dnme
    Registered Users, Registered Users 2 Posts: 3,453 ✭✭✭dnme


    https://www.boards.ie/discussion/comment/123980844#Comment_123980844

    That's really observant, well done. I'm after going outside there with a flashlight but I cannot see this. I'll try again tomorrow in the daylight. I might try magnification with the phone. I'll let you know how I get on.



  • #18
    batistuta9
    Registered Users, Registered Users 2 Posts: 8,630 ✭✭✭batistuta9


    use a hose & soak the wall above to see if you can figure out what's happening



  • #19
    Escapees
    Registered Users, Registered Users 2 Posts: 951 ✭✭✭Escapees


    In terms of identifying the source of the issue, you could leave a hose running on the wall above the reveal to rule stuff out, even blocking off any external path to the window frame with some cardboard and gaffer tape during the test etc. The great thing is that you don't need visibility from the outside and can just observe from inside the house during any test.



  • #20
    dnme
    Registered Users, Registered Users 2 Posts: 3,453 ✭✭✭dnme


    Sorry for not responding sooner. I was busy and weather etc. Today was fine so I went out to try and have a decent inspection of the window. I notice the area of the upper reveal right above where I am seeing streaks, still seems damp compared to the rest of the reveal. So I looked closely above that area into the pebble dash. About a foot above the reveal, I see a vertical hairline crack. Is it possible this crack is taking in water and that is then causing the streaking? Do you reckon this could be my problem?

    PXL_20251116_160939832.jpg

    PXL_20251116_160945054.jpg

    PXL_20251116_160953468.jpg

    PXL_20251116_161033034.jpg


  • #21
    con747
    Registered Users, Registered Users 2, Paid Member Posts: 10,666 ✭✭✭✭con747


    It looks damp all around that crack, could the water be penetrating it and run down to the top of the reveal and back to the window and be running down?

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  • #22
    dnme
    Registered Users, Registered Users 2 Posts: 3,453 ✭✭✭dnme


    https://www.boards.ie/discussion/comment/123993685#Comment_123993685

    No I think what you are seeing is the old pebble dash against the new pebble dash. We created a new picture window last year and the plasterer had to redo the pebble dash around it. So that's what you're seeing there.



  • #23
    con747
    Registered Users, Registered Users 2, Paid Member Posts: 10,666 ✭✭✭✭con747


    https://www.boards.ie/discussion/comment/123994174#Comment_123994174

    Is it still possible the crack is letting water in to run down and run onto the window from the reveal? Is the reveal tilted in towards the window? A level will show you. I'm probably completely wrong here!

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  • #24
    Escapees
    Registered Users, Registered Users 2 Posts: 951 ✭✭✭Escapees


    An interesting question is does the drip start immediately when it rains or after a good while? And does this change if it's already been generally wet? Like I suggested before, just taping a sheet of cardboard or plastic to the top part of the frame to shield the top of the glass from surface water would tell a lot. If the drips continue under the shield, then you have confirmation that there's water collecting in the frame itself and leaking down from this...



  • #25
    deandean
    Registered Users, Registered Users 2 Posts: 2,427 ✭✭✭deandean


    OP here's a different approach you can try. Get an automotive windscreen ceramic rain-repellant treatment and apply it to the outer surface of the glass. E.g. Gtechniq G1. I use it on my home office window and it's brilliant. Water never remains on the glass. A good treatment might cost you €50 but well worth it IMO.



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