Internal leak under window sill (anyone suffered this before)

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2016_0126_16442500-01.jpeg 2016_0126_16450400-01.jpeg Anyone else suffered from similar?
After the high winds and rain this morning we have gained a leak.
The wife was in the house at the time and she described the sound as like running water and it took a towel to soak up the contents.
Rain has stopped so leak has stopped.
Visual on the roof suggests all ok there.
Check of the silicone on the outside at the edges of the window shows shrinking and thus a 1-2mm gap in the wall.
Firstly would this be enough to let wind drive rain in in such great quantities.
Secondly we have cavity walls so i cannot figure out if rain water could realistically penetrate that far through.

Any other thoughts?
 
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Is the gutter above blocked, often runs down the building. I'd redo mastic and check mastic seal between sill and window too
 
Gutter not blocked that can be seen.

Should mention that its a ground floor window. Neighbour above has same size and position of window bit they report no problems.

Now that the rain has stopped ive been out and put fresh mastic on to fill the gaps as a temporary fix to see if it cures the problem.
 
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stupar said:
Gutter not blocked that can be seen.

Should mention that its a ground floor window. Neighbour above has same size and position of window bit they report no problems.

Now that the rain has stopped ive been out and put fresh mastic on to fill the gaps as a temporary fix to see if it cures the problem.
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Mastic certainly won't hinder it, did you check between sill and frame? I always point in with sand mastic along there with a flat pointing key
Have a look at the gutter next heavy rain tho as I always suspect that first when I hear these reports. It takes hard driving rain to cause problems even if mastic isn't great but it does happen
 
Just seen the photos, never seen them first time, I'm now suspecting the seal above sill as its along that joint. If it was coming in the jams I'd suspect it to be in the corner and downward, not horizontal like yours

Edit to ask, have you had sills or anything changed recently on external elevation? Some handymen types might not know to replace dpc tray behind the sill
 
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Gary Coyle said:
Modern PVC windows will have a drain hole built in somewhere, check it isnt blocked
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Access to drain holes is impossible without dismantling window as it has no openings (unless im missing obvious access)

BruceMo said:
Mastic certainly won't hinder it, did you check between sill and frame? I always point in with sand mastic along there with a flat pointing key
Have a look at the gutter next heavy rain tho as I always suspect that first when I hear these reports. It takes hard driving rain to cause problems even if mastic isn't great but it does happen
Click to expand...

There is a gap where the frame sits on the outside sill ( i assume the gap is deliberate to allow drainage)
Todays rain was horizontal and certainly driving into the window, that could just be shear coincidence though.
Will check the gutter at next rain fall just to be sure.
 
We have a leak above our window with similar results (although the water drips from above onto the windowsill). It's the render on the wall outside which has cracked, allowing water penetration. Unfortunately, it's too wet (or cold) for a sustained period at this time of year to re-render or even patch. What's your external wall clad with? If it's just brick, it might be the pointing which needs to be repaired.
 
Did you check on the underneath of the "external window sill", as that may not have been correctly pointed in or sealed with mastic?
 
BruceMo said:
Just seen the photos, never seen them first time, I'm now suspecting the seal above sill as its along that joint. If it was coming in the jams I'd suspect it to be in the corner and downward, not horizontal like yours

Edit to ask, have you had sills or anything changed recently on external elevation? Some handymen types might not know to replace dpc tray behind the sill
Click to expand...

Nothing done since the windows were installled 2 years ago.
When you say the seal above the cill do you mean between the cill and frame?
 
lostsoulal2 said:
Did you check on the underneath of the "external window sill", as that may not have been correctly pointed in or sealed with mastic?
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Checked that when i carried out a temporary fix, it looked water tight to the eye short of doing a hose test.
 
stupar said:
Nothing done since the windows were installled 2 years ago.
When you say the seal above the cill do you mean between the cill and frame?
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2 years? Get the window fitters back to sort the problem.
 
Nod said:
2 years? Get the window fitters back to sort the problem.
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Tried that, they said i wasnt covered for blocked drains or worn mastic etc.

Going to dig out the documents tonight to see if that is true or not.
 
stupar said:
Nothing done since the windows were installled 2 years ago.
When you say the seal above the cill do you mean between the cill and frame?
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Yes, between concrete sill and window frame should be sealed with mastic. As I said above I do this junction with sand or trowel mastic
 
BruceMo said:
Yes, between concrete sill and window frame should be sealed with mastic. As I said above I do this junction with sand or trowel mastic
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Ah i see.
The houses we stay in dont have concrete sills. Its PVC cill on top of brickwork.
Our window wall setup is similarcto the cross section shown below
UK_sill-01.jpeg
 
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there seems to be allot of make-up around the windows, also returned on the corners, never seen that before,could be hiding a multitude of sin's, installed plenty myself and seen many installed, i would be inclined to take the sill off and see if you can see it better, it could be tracking from anywhere, if neighbours window is in-line with yours check there is no cracks in the upstairs sill..
 
I'd say if that drawing was accurate that would be a potential fail as their is no dpc tray to prevent capillary action and would actually explain the problem but I'm guessing it's not
It does demonstrate the need for mastic beneath the sill tho, the dpc barrier is a secondary defence that shouldn't be needed in a perfect world
Mastic seal every part of the meeting between frame and building, check the gutter then see what happens
 
Two year old installation and you appear to have a water leak potentially as result of a failure of the installation.......... were I in your shoes I would get the company back to fix it under warranty unless of course not worth the ink it was printed with!

Surely up to them to sort it out or state in writing what they will not do so! Was it one of the majors or a smaller local company, either way they should do it. As for them blaming the mastic and saying not covered........ IMO hogwash, unless of course your contract has a clause that maintenance is to be done with proscribed material and process.

If push comes to shove name & shame them!

Edit - that white strip under the cill IMO is covering the sins of the installation.....and is the same PVC on the vertical surfaces of the rebates, if so curiouser and curiouser??? If they failed to 'make good' before covering the rougher edges I wonder how high the chance that water ingress anywhere around the outer edge of the frame is wicking the water to the lowest point as seen in the picture?
 
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I think the company are trying to fob me off.
I checked my warranty last night and there is no clause about only being covered for servicing to the windows for 12 months so i reckon they are trying to palm me off with excuses.

Incidentally more heavy rain came last night but without the driving winds and this morning the inside wall was dry, so i wonder if that plus my re doing the mastic outside has solved the issue.

As a further precaution I am getting someone out to check the roof and gutter to make sure there is no water ingress at that point.

If the roof/gutter checks out fine and the problem comes back though i plan to just get in touch with the company and play the defective installation card.
 
The modern way seems to be to air their damp laundry on social media - gets quicker and more satisfactory results than polite conversation apparently...
 
stupar said:
Incidentally more heavy rain came last night but without the driving winds and this morning the inside wall was dry, so i wonder if that plus my re doing the mastic outside has solved the issue.
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I had exactly the same issue a few years ago, the putty under the sill had dried out and shrunk leaving a gap and rain water got blown in by the wind. I dug it out and replaced it, no problem since. I have to say though it took a lot more than two years for my problem to surface!
 
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