# Leaking Milgard vinyl windows (occasionally)



## lazzlazz (Mar 29, 2010)

4 years ago I purchased a house built in the late 1990s.
It has vinyl Milgard windows, 4 of which have minor leaks occasionally, usually when it's raining and quite windy. They all leak only on the right side - which is the side which opens when the windows slide to the left - and only in a fairly narrow zone. See picture with drip spots - the water seems to be making its way to the inner edge of the window & then drips down.

I'm looking for some suggestions on how to permanently prevent this leaking. The house has a full 2nd story & 2 of the leaking windows are difficult to reach because of porch roofs under them.

Currently, the leaks to the interior are fairly minor. However, on a few windows, the MDF lining the inside of some of the window frames shows evidence of swelling toward the top of the windows so it's a problem I'd like to solve.

See pictures. 

The previous owner of 10 years did no work on the exterior. After my first year in the house, I caulked the windows I could. For one of the 2nd story windows, I took off the screen & just tried to add caulk (blindly) to see if that would help - I don't currently have a good way to access that area safely (I've thought of investing in a climbing harness & ropes, and may do that in the future - that would allow me to paint & caulk around the trim). It seemed to slow down the leaking. 

For the 2 first-floor windows, I caulked over the existing caulk. That seemed to help to a point. 

Last summer, for one of the first floor windows, I removed the inside wood trim from the top of the window. The trim around the window was MDF (note: my exterior walls are thicker than is standard, 2x6s, rather than 2x 4 studs). I chose this window because the water damage on the top horizontal trim was the worst - you could see it had swelled quite a bit at one point. (I had replaced & caulked the exterior trim on this window after I had owned the house about 10 months - the trim was rotten because of lack of maintenance & this window gets the most southern exposure).

There is about a 3/4" gap between the top of the window & the framing of the house. There was no flashing that I could see - there was certainly none wrapped over the framing at the top of the window. On the "out" side, one strip of foam pipe insulation had been squeezed in between the framing of the house & the top horizontal strip of wood trim above the window. Since I had some of that around, I replaced it with another piece to see if that (plus the exterior caulking) would help. (This past winter, I removed the interior top piece of trim from another window & found that it too had this foam pipe insulation so I'm wondering if this was put in by the original builder (this cannot meet code??) - there was really no indication (no extra nail holes) that the previous owner had ever removed the wood trim, unless a new piece of trim was installed). I replaced the top horizontal strip of MDF with pine - I figured solid wood would stand up better against leaks if the exterior caulking hadn't solved it. This window did not leak this past year (I'm in the northwest so we get rain from fall to spring) on the interior side.

*The windows have no drip cap.* Modifying the windows to add the drip cap would be a good amount of work, although digging out & recaulking the exterior every few years is a lot of work, too. Should this style of window have drip caps? Above, I mentioned that there seems to be no flashing - I didn't see any when I removed the inside trip along the top of the window. I'm guessing the only way to add that would be to remove the window frame? (I'm surprised as I live in a major metro area whose building inspectors seem to be fairly strict - and I thought code required flashing?).

I've started digging out the existing caulking above one first floor window & am planning on re-caulking. The vinyl window sticks out close to 1/4" from the exterior trim, which I'm guessing allows water to sit on the lip & work its way in. I'm planning on putting a good deal of caulk on to try to create a slope so the water slides down the caulk & doesn't sit on this lip. 

What is the best way to solve this leaking problem? Only 4 (of 8 total) windows are leaking now, but I assume others will likely develop the problem. Short of removing all the windows, and flashing & installing a drip cap, is good caulking the best solution? What is the best caulk? I looked at options at HD, and thought DAP Dynaflex 230 (exceeds ASTM C 920, class 25) - indoor/outdoor sealant, waterproof & paintable, might be the best option - does anyone have other suggestions?

This house has the 4 x 8 sheets of siding on the 2nd story, with vertical wood strips every 2 feet or so (presumably to cover joints & nail) - plus a wide horizontal board at the bottom of the sheet, where it meets the clapboard siding (full of knots) on the first floor. The newer construction materials & approach used in this house seem critically dependent on the owner maintaining the caulking around the windows & siding.


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## lazzlazz (Mar 29, 2010)

Pictures. top picture shows evidence of dripping.

Middle picture shows where I've started digging out the caulking on one window (with plans to re-caulk). You can see in this picture that the exterior trim above the window also has a lip that sticks out from the clapboard over it. It's also possible that water that sits on this lip can work its way in - so I'll caulk that better too.

Bottom picture shows the type of pipe foam insulation that I've found crammed between the top of the window & the framing above the window in 2 windows (after removing the interior trim above the window).


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## Windows on Wash (Aug 30, 2011)

Picture from further back?


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## lazzlazz (Mar 29, 2010)

Here's a picture of the exterior from further back. All exposed wood is from me digging out the caulk today.


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## lazzlazz (Mar 29, 2010)

Here is an interior picture. The 3/4 inch gap between the window & framing in the exterior wall is hidden by the top horizontal white wood trim (I haven't yet covered the nails). I'll look to see if I took a picture of this gap when the trim was off - I might have but it probably isn't a very good quality picture.

The horizontal piece I replaced in one window can just be seen - it hangs a little below the horizontal trim running along the wall. If you're wondering: how did they attach the MDF that originally was there, since there was a 3/4 inch gap? They stacked thin slices of MDF (sometimes several) until the gap was full, & then nailed through that. There were 3 or 4 such stacks - the window is about 68" wide. Not an elegant solution, but I guess it got the job done, & it wasn't contributing to the leaking.


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## kwikfishron (Mar 11, 2010)

The lack of proper head flashing above the trim makes me question the entire siding installation. How about a picture standing way back showing the entire wall (exterior). 

Don't be so quick to blame Milgard.


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## lazzlazz (Mar 29, 2010)

I never blamed Milgard in anything I said - everything I said should make it clear that I blame whoever installed the windows when the house was built. I'll try to get the full exterior shot later tonight. It looks the same all around so the exterior shot I put in above should provide that detail.


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## kwikfishron (Mar 11, 2010)

lazzlazz said:


> I never blamed Milgard in anything I said - everything I said should make it clear that I blame whoever installed the windows when the house was built.


Sorry about that...I admit to only reading half of the long post and jumping to the pictures although the thread title imply's something else.


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## Windows on Wash (Aug 30, 2011)

What is above the windows...i.e. next floor up.


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## lazzlazz (Mar 29, 2010)

Windows on Wash said:


> What is above the windows...i.e. next floor up.


If I understand the question:
Above most of the windows is just siding (first floor is clapboard; 2nd floor is that 4 x 8 siding you see on newer houses). Above the one I've been working on (digging out caulk) is a porch roof (about 5 feet deep) and then another window. This is the only first floor window that has a 2nd floor window above it. 

I don't always get the leaking in the 4 windows where it happens; there seems to need to be some wind and a decent downpour. And it's restricted to a fairly narrow area on the right side of the windows. It seems to come in where the window frame meets the trim on the interior side of the window. You can see there is a little discolored area at this point in the picture I posted showing the evidence of dripping.

I find it interesting that it's always coming in through a narrow area on on the right side of the window - the side that is open when you slide the slider window to the left.


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## lazzlazz (Mar 29, 2010)

I suspected this could be a tricky problem to diagnose _ I just wanted to see if anyone here had any suggestions/experience with this kind of problem.

Perhaps I should try the caulking approach (digging out old & installing new such that water sheds rather than has anywhere to sit) & see where that gets me? There isn't likely to be much rain before Sept. & then it's pretty constantly wet. At least the leak is minor. (My biggest concern is whether more damage is being done unseen to the framing, but that's replaceable.)

If the caulking does/does not work, that tells me something. (Caulking over existing caulk helped last year.)


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## kwikfishron (Mar 11, 2010)

You are correct these leaks can be tricky to diagnose and there's a systematic approach in troubleshooting these. 

You say now that there's sheet siding above the clapboard. That transition from the clapboard to the sheets is something I'd be looking at. It's hard to offer much more from here especially with only seeing a partial picture of the area.

I've seen leaks that only showed up above a first floor window such as yours that were caused by a second floor roof leak.


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## lazzlazz (Mar 29, 2010)

Thanks for that info - that is my biggest fear, that the leak is coming from somewhere far away. I'm hoping that since the windows all leak on the right side indicates that the problem is coming from near the window opening.


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## Windows on Wash (Aug 30, 2011)

Post up a picture from farther back....that was my point. :whistling2: :thumbup:


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## jakopotamus (Aug 8, 2015)

Did you ever get these leaks fixed? I had/have the same problem, I was able to get a piece of flashing behind the siding with it extending over the edge of the window. That fixed the leak i had coming over the top of the window from the nailing flange being broke from not being installed correctly... anyway, I now have water coming into the bottom corner and I'm not sure if it's a leak through the sash/frame or if the flashing I installed is sending water down the side and getting in somewhere.


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