# Leaky Bay Window



## Mo Heat (Jun 20, 2007)

Starting up a new thread on my bay window. Here's a link of mention of it in the leaky shower thread just for reference:

https://www.hearth.com/econtent/index.php/forums/viewreply/93476/

Executive Summary

While I was blissfully ignorant, one of six bay window sills rotted away before I realized what the crinkling latex paint was trying to tell me (see: photo 1).

Then, one morning, after a big cup of joe, I decided to push my finger on that window sill, come what may. Here's what happened (see: photo 2). That's not good!

So I whipped out a little saw and did what my gut was telling me I was going to regret (see: photo 3). Holy crap! What's going on in there, and what's he doing in my wall (see: photo 4)?

Houston, we have a problem.


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## Mo Heat (Jun 20, 2007)

Ten minutes later, here's what's left of the window sill (see: photo 2). A half hour later, I've had my way with that window sill (see: photo 1).


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## Mo Heat (Jun 21, 2007)

So I caulked the heck out of those windows using expensive urethane caulk. But I think there are still a couple more places to caulk that might help and that might actually be allowing water in. I've had a couple little rains, but nothing to really test them. I guess I'll go out with the water hose after I get the newly discovered areas sealed up, even though I'm not certain as to the construction details of these windows, and don't know where they are likely to leak (see: photos). They look like they should leak from just about everywhere. 

Check out the flashing and the lower cedar siding boards above the bay window shingles (see: photo).

Check out the unfortunate location of the disintegrating knot (see: photo).


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## nshif (Jun 21, 2007)

Mo
That really doesnt look good.  Probably to the point of structural damage which you arnt going to fix with caulk. Plus its created a bug haven which will only make it worse. This may be a bigger problem then your deck issue.Im going to go back to your post and look at the pics again before I suggest you rip off the siding, remove the windows and replace the framing.


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## Mo Heat (Jun 21, 2007)

Don't try and stop me...
I'm going to jump!


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## Mo Heat (Jun 21, 2007)

nshif said:
			
		

> Mo
> That really doesnt look good.  Probably to the point of structural damage which you arnt going to fix with caulk. Plus its created a bug haven which will only make it worse. This may be a bigger problem then your deck issue.Im going to go back to your post and look at the pics again before I suggest you rip off the siding, remove the windows and replace the framing.



nshif, When I pulled all that rotten wood out of the window sill, I was amazed, but the frame member that it sat upon was totally unaffected. It was as dry as a bone even though the sill was soaking wet, like a wood fiber sponge. It looked like the sill was tilted away from the house and to the left, so all the water was dripping to the outside. I do notice a bit of water discoloration on the bottom of the bay soffet (I think that's what the bottom of the bay is called), but I'm thinking, and hoping, that is about it as far as damage goes. Here's a picture of the bottom of the bay window where I think the water was coming out.


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## Mo Heat (Jun 21, 2007)

You can also see carpenter ant holes if you look closely. The little whitish circle on the left, if I'm not mistaken.

I've got Amdro out all over the place and I think it's doing its job.


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## Hogwildz (Jun 21, 2007)

Ok Mo,
lets take this a step at a time. This is one of my old roofing/siding specialties. 
The cedar/ flashing are not terribly bad. Cedar will crack at spots. No biggie.
First thing I ask is if possible, take a full photos of the window with the roof over it & firs couple of courses of siding showing in the one photo.
Can you tell or see how far that flashing between the bay roof & cedar siding goes up behind the cedar? 
I am wondering why the flashing there follows the bay roof line then jets out then up under the cedar? If it does not extend up past the first course of cedar its not correct.
See that vertical seem in the cedar? can u see between it and see if the flashing goes up past there, or stops midway or short under that seam? If it is short, you can slid a 3" x say 6" or 8" piece of sheet metal, alum or copper up under it vertically to flash the seem so to speak. even a pc of roofing felt would work. If it is indeed short of getting up past the seam, any water that runs in there will run behind that flashing & follow the wall or even the shingles on the bay window roof underneath and hence come in at the window underneath the roof, depending on how the roof was put on and whats underneath.

Now to address the tops of the window area. That pc between the window, even if it got water in, should drain out the bottom the same way it got in the top. Unless the bottom is closed off. You can use the urethane there and it will be fine. One step better would be install a pc of flashing the a lil longer than the complete width of the windows that extends a couple inches beyond the end windows on each side. It would extend up behind that pc of cracked cedar until it reached just under the next course of cedar. What sticks out under the cedar would be bent just enough to come down & just clear the window edge. then a small 1/4" or 1/2" slight bend down to form a drip edge on the very bottom edge of the flashing. If I lost ya, lemme know and I'll draw a picture. Keep in mind if you can & do open those windows, if they are casements and open outward, you will have to be more precise with your bottom of the flashing length & drip edge. If it hangs too low with casement windows, it will block them from opening. 
When replacing that sill, I would thinking about maybe using cedar, or even hemlock, as the bugs don't like that stuff. Hemlock is great for repelling insects. Or even use some pressure treated. Same results.

As far as the bottom soffit  area of the bay, don't sweat it, it looks good. If your going to caulk all the seems & such. Make sure you have the upper leaks stopped first. Caulking the bottom before that would keep the water if any from running out & draining. Possibly causing more leaks. Once your sure the top is tight, then seal sparingly at the bottom to keep the bugs out.

I understand its easier for me to see in my mind, and again if I am making it hard to follow me, just hollar and I'll draw it. If you need to pm me and I'll call you or vise versa and try and help. Man I wish I was closer. That window & roof flashing fix is easy.


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## Mo Heat (Jun 23, 2007)

Thanks Hog. I'm pressed for time lately, but will update and respond to your excellent advice ASAP. I appreciate the encouragement and am glad you believe it to be an easy (for a pro) type fix. I like several of your ideas and when time permits, I'll update. Again, thanks... very helpful. Got to run.


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## Mo Heat (Jun 23, 2007)

Just have a couple minutes before leaving again...

First, I believe I've found and fixed the source of the bay window leak that destroyed (with bug help) the sill. I removed the caulk from the bottom of the window and found some poor workmanship. The cedar siding board just below the window was essentially bowed in the middle and drooping. Good lord, there was at least 1/2 inch of caulk in there to try and fill the 1/2 inch gap that spanned pretty much the whole middle two window panels. That was a big gap.

I pulled that board off and a whole lot of dead carpenter ant soldiers fell to the ground in a cloud of wood dust and crap that I was trying desperately not to breathe, but I could only hold my breath for so long up on that ladder before I nearly passed out and fell off. Uhg! (see: photo)

I took that bottom board and cut a straight line (not easy) and fitted it until it made a nice butt joint against the bottom of the window frame. (see: photo)

(Got to run, I'll post the photos mentioned above, and more later.)


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## keyman512us (Jun 24, 2007)

MO...
...I might not try to stop ya..lol J/K But I would get "used to spending some time on that ladder." I take it you had a "re-roof" recently??? I'll take a stab at it..."Wheatstone/Wheatridge" something along those lines 30YR architectural shingles??? I'de guess either Tamko or GAF...kinda hard to tell by the picture...lol 
At risk of sounding like my buddy Elk (J/K my friend)...That ain't BOCA! The flashings leave "a little something to be desired"...Ideally, there should be bitchathane (ice and water shield) under those shingles on the dormer style roof of a bow window. Hopefully you don't have any water working it's way under the shingles in the winter. But assuming there is no issue there... The tops of the window...I'm surprised don't have "some sort of drip flashing"... While caulking does a good job...It's no replacement for flashing. Metal, metal,metal...I always say. You can't have enough of it. If it were my dilema to deal with...here's where I would start: Get some metal flashing over the top of that window unit. Pull some nails, get out the pry bar, and slip some metal in there. Without "real measurements" it's hard to say. Run to either the local supply type hardware store, Loews' or HD and ask for some "Dark bronze or oil rubbed bronze colored Z-style flashing, "Brick Mold" style...sounds about right." If the orange apron gives you a puzzled look..."You know, the metal flashing you would 'wrap a piece of brick molding with'..." It's about an 1 1/2" by an 1 1/8th with a 1/4" return...comes in a ten foot length. Get a pair of tin snips and practice your hand at "being a tin knocker". At around $4.85 a ten foot length...it's short money to solve problems...A "drip Cap" over that window wouldn't hurt...


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## Mo Heat (Jun 25, 2007)

Here's the photos:

1. Bottom of bay window where caulk looked suspiciously leaky. I could see water coming in here when it rained. It would then run along the bottom of the window to the other side where all the spongy wood was that I removed.

2. Here's what happened when I pushed my finger on that funky looking caulk. Quite a gap to be filled with caulk. And it looked like that below both the middle windows and parts of both the side windows; a majority of the joint. No wonder it was leaking.

3. When I pulled the cedar board just below the window I found evidence of active carpenter ants.

(continued in next post)


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## Mo Heat (Jun 25, 2007)

1. Here's some of the ants that fell out from behind that cedar board when I popped it off.

2. If I'm not mistaken, this is a wood boring beetle just waiting in the wings for me to get everything back together.  :gulp: 

3. Here's the freshly sawed and fitted cedar board below the window before I applied urethane caulk. It has a lot less gap and will make a nice caulk joint. I was pretty proud for a complete rookie with a $5.00 garage sale skill saw with a bad cord.  :cheese: 

4. The newly caulked (urethane) cedar board.


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## Mo Heat (Jun 25, 2007)

1. The left side had about a half inch gap after I butted things over on the right so I put in a piece of the trimming from the cedar siding cut to get less than 1/4 inch gap to caulk.

2. The finished product.


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## Mo Heat (Jun 25, 2007)

Now for the top of the bay window, your requested photos, and suggestions...

Hog, Is this what you are looking for regarding the top of the window and first courses of cedar siding?

This is about as good as I think I can get due to the hill, trees, and deck obscuring the view. I can't get back far enough on the ladder to get more than about 4 feet of width.


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## Mo Heat (Jun 25, 2007)

Keyman, I'm going to look for some of that bronze flashing next trip to the hardware store. This place was re-roofed about 5.5 years ago. Above that bay window is the worst looking place I've seen. Everything else looks pretty good to my eye, which is admittedly uneducated in roofing, but the section over the bay window looks bad even to me, at least, it looks unusual. 20 or 25 yr Tamco shingles IIRC. Bitchethane? Man, names don't get much cooler than that!  :coolsmirk: 

Hog, I'm going to look for some Hemlock, and failing that, some PT for the sill. I'm pretty sure I still have some ant activity in there as one comes out and dies now and then. Probably from either the Amdro I've put outside or the Raid I sprayed inside the sill.

I think my existing flashing below the cedar board closest to the top of the window is only about 3 inches high. Is that high enough?

If I find the flashing, I'll likely have some more questions after my first pass. I've got a pair of tin snips already. I like the idea of a drip edge above the windows. BTW: the four windows in the middle of the bay do NOT open; only the two casement windows on the sides open and they both have a little eve hanging over them which seems to cover them pretty well in the rain.

And I used the urethane on the top window assembly joining points as suggested (see: photo). It ain't too pretty, but it should stop any potential leaks. I can see that those strange joint looking areas between the panes are some sort of modular hardware connectors for putting as many of those panels together as you want. A modular type design. I guess you knew that already and why you weren't worried about water getting in there. It does look like it will just run out the bottom as you said.

I'll reread both of your posts to make sure I'm understanding and have answered all your questions.

Man, this thing is starting to come together. I may be moving on to the deck problems pretty soon if all goes well.  :gulp:


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## keyman512us (Jun 27, 2007)

Mo Heat said:
			
		

> Keyman, I'm going to look for some of that bronze flashing next trip to the hardware store. This place was re-roofed about 5.5 years ago. Above that bay window is the worst looking place I've seen. Everything else looks pretty good to my eye, which is admittedly uneducated in roofing, but the section over the bay window looks bad even to me, at least, it looks unusual. 20 or 25 yr Tamco shingles IIRC. Bitchethane? Man, names don't get much cooler than that!  :coolsmirk:



Mo... (as a locksmith)You would love to see the look on someone's face when you tell them "Gotta run back to the shop for some sex bolts..." lol

"Locksmiths get it right...Cause' they hang alotta hardware with sex bolts..." lol


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## Gooserider (Jun 27, 2007)

The stuff you've been doing so far looks good, but I'm not sure it's on the right end of the problem...  I'm not an expert on the construction details, but I do know that water generally does not flow uphill, or even just horizontally around corners.  Maybe I'm stating the obvious, but it looks like a great deal of the work you've been doing has been at the bottom edge of the window, and I really doubt that water has been going IN at that point.

I'd be suspecting that what you are seeing under the windows is water getting in at a higher point and flowing down to under the window where it is trapped while trying to get back OUT!  If this is the case you might actually be making things worse by the excellent sealing job you've been doing under the window, that in effect is making a more effective water trap.

I'd suggest spending a lot more effort on going through the upper parts of the window, and the roof over it, to make sure that there is no water getting IN...

Gooserider


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## Hogwildz (Jun 27, 2007)

3" ain't too bad Mo. The trick is to see if there is any horizontal or vertical cracks above where the edge of the flashing up behind the cedar is. And vertical joints as well.
If you can see in any crack or joint, and see the top edge of that flashing. The water can see it too and get in above the top edge of the flashing. Usually on a certain driving rain that would pound against the cedar & flashing. But if it looks tight, 3" should be sufficient. I am wondering how you saw the flashing guestimate the 3".
If you were seeing it through a crack or joint, then water driven rain will find it also.

The urethane caulk does an excellent job of sealing. Lasts a long time also. I would still suggest a drip edge flashing up a couple 2-3" under the roof edge, then bent down over the window tops with a 1/2" kick out or "drip edge" to be specific. But tis hard to tell all from pictures, well not as easy as seeing it in person. If its tight along where the window meets the siding. You'll be ok for a while at least. But it should have had a drip edge flashing under the cedar & over the window edge to seal it off. Then caulk would not have been needed.
 After looking at the full picture, I really don't see alot of water getting to that small bay roof. If you can make sure the top of the bay roof meets the siding is tight, and the lower edge over the windows is tight. you should be golden then. That roof just will not see enough water to cause a major floodstorm in those windows.

Pretty much same goes as missing flashing at bottom of other window. Where u cut & replaced siding & caulked. Will most likely be trouble free for some time hopefully now. But windows should have a base flashing at the bottom that the window actually sits on, with the same type drop down & drip edge. Same at the top with a pc of header flashing. At this point that may or may not be involved. I have snuck pcs of flashing over or under windows before. But a few tight spots make for a miserable day.
Just be careful  NOT to caulk natural drainage paths built into the window system(s). Yes I was not overly concerned with the modular channels, as they run vertical and are made to drain naturally. The channels are basically outside the house or room. Almost all windows, doors, sliders etc, have drainage provisions. You want to make sure to keep these clear & clean. 

Agway sells a really good granular product to kill ants etc. Just a pour a lil in when putting your wood back in then forget about it. Might even be the stuff  you mentioned. My mom uses it and swears by it.

It seems to me you have the leaky drain & these windows back under control and performing as expected. If ya want, get your hose out and douse the top of the bay window roof, the siding where the flashing from the bay roof meets it. anywhere you feel might have been a leak path or problem. I do however suggest starting at the lowest point and spraying your way up. checking periodically at each height advancement. If you test with water at the top first, it could come in there and drain lower, giving you some guesswork as to where it originated from. Starting low and checking as you go up. You will know exactly at what height or level the water is coming in, if it ia at all. Still sounds like you solved 2 major PITA problems. Thats a great feeling, I know, I am on red alert every other day here" Oh Mr. fixit man". But it feels great when a problem is fixed and you can breath a sigh of relief along with feeling some pride in a job well done. I just hate fixing builders or previous homeowners F-ups. But we all do, and you will with any house.

If ya have any other questions you have a couple folks here that can try and give answers. Let us know the next project, so we can help prepare for the remedies if able  .


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## Rhone (Jun 27, 2007)

I was thinking the same thing, the bottoms of those windows should have some kind of a drip edge.  Water can, and does flow up hill proof being my roof.  Look at the picture.  My roof didn't have enough pitch the water would come down, loop back towards the house and come down behind the gutter (only in certain areas).  During rainy weather, I took a ladder and noticed where the water was dripping behind the gutter was the same places I couldn't see water dripping off the roof into the gutter.  So, it was working up and looping around.  The fix, was to make a drip edge that went underneath the last shingle that hung into the gutter and the problem was solved.  I think any rain hitting the window in your case won't drip, it looks like the water will have an easier time going backwards towards your house underneath and then you can hope it will fall down the shingles.  I wouldn't depend on caulk in that location, use some sort of flashing but, I know very little about caulking, flashing or water proofing for that matter.


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## Hogwildz (Jun 27, 2007)

Damn good diagrams man!! Your correct. Most think water will just run down & drip or fall off. But it will follow  the lines of the object it is running down.
The "gutter helmet" or other gutter cover that let leaves fall off but the water follows the curves into the troughs is a perfect example. On roof edged with gutter, the other problem is in winter with daytime thaw and re freezing. The gutter get filled and actually build up higher than the gutter & roof with freshly frozen run off. This is damning.
This is the reason for ice & water shield at the last 3 feet of roof above the gutter. That way if water does freeze & back up under the shingles, it does not get to the substrate and rot the wood out. Drip edge is cheap, and its performance makes it worth 100x its cost.


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## Mo Heat (Aug 11, 2008)

Been a while,  but thought I'd update my window situation. I've been through several iterations of caulking with less than success and I've discovered at least two other windows leaking in a similar fashion as the bay window. All are exposed to rain with little shelter from roof overhang, etc. It looks to me like a poor window design. 

I'm no expert, but the metal window bottoms seem to channel or wick water behind the bottom boards. Because of the window design (circa 1998 Pella), any attempt to add a bottom drip edge would still rely upon caulk to keep water from wicking behind the lower board (cedar), so I've simply caulked things and gone to an additional sledge hammer approach. I removed and beveled one of the 2 x 8 cedar bottom boards to promote "drain away" technology.  I also made some "not too ugly" visors out of roof flashing and mounted them above three of the offending windows to minimize driven rain exposure.

The three visors that are up (the experimental bay visor needs to be taken down, trimmed, and the cedar strips stained) have not had enough rain to determine exactly how effective they are. In the one driven rain I've experienced, the bay window did seem to leak much less, but still leaked a little. I think even the vertical channels may be leaking at this point and I may try and pry one of them off if I get fed up enough and see if I can caulk them back into place with a better seal. Disappointing, but I think I can live with this trace moisture rather than replace a zillion high-dollar windows.

I'm rebuilding the bay window sill with that plastic board stuff that looks like painted wood (see: photos in link).

Thanks to everyone for the help and encouragement.

Here's some pictures: 

http://picasaweb.google.com/moheatmail/20080811WindowVisors?authkey=KQiK8iuGu8A


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## begreen (Aug 11, 2008)

Pella is a pretty good company and often will send out a rep to investigate. Most of the time it is not the fault of the window, but the installation. Your windows are similar to ours, but our Pellas are all wood.  

You might want to start with a simpler window assembly than the bay for the first try. Odds are if they made a mistake in installation, it was repeated on the other windows. It's hard to tell without removing the siding around the windows, but I am suspecting an error in the sequence of flashing that is letting water go behind the window. This might happen if the house membrane was behind instead of on top of the upper nailing fin. That's just a guess though. Without removing the siding around the affected window it's hard to see what is happening behind the siding. The window could be installed correctly, but water could be traveling down behind the siding from a higher point until it hits the window. 

FWIW, a conventional window sill goes uphill from the outside edge towards the window body. And most importantly, there is a kerf (groove) about 1/2" in from the edge on the underside to prevent the laminar flow of water running over the edge and back towards the house.

PS: How is the hillside stabilization project going? What was the solution there?


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## Mo Heat (Aug 21, 2008)

I still haven't gotten past the wringing of hands and the gnashing of teeth on the hill stabilization project or the deck repair. I'm currently cleaning out the garage and basement so I can have the termites evicted. Where did all this stuff come from and why am I certain I'll need it in the future when I haven't needed it in the last 10 years?. It never ends.


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