Rotted wood interior window

I posted about some cracks around the interior of a bay window a few years ago and got some advice about caulking. The caulking has now cracked again and there was a small water stain on the window sill. There is also now some further cracking by some caulking under a different window of this bay window where I can now see wood (middle picture below). I dug at the wood a bit with my finger nail and the wood chips away easily. The previous owner had the windows in the front of the house, including these, replaced. The upstairs windows are fine but one of the bay windows fogs up and another of the front windows fogs up. Can a broken seal on a window cause water damage like this? My neighbors have used a licensed and insured handyman for all different kinds of jobs from carpentry to drywall, I'm probably going to call him to come take a look at it but I wanted to post here to get some background knowledge/info as I'm not that experienced with this sort of thing. My worry would just be that the wood would get replaced but then rot again. What would cause interior wood like this to get water damaged? How is the water getting inside? Or is it just underneath the window and then the water is working inward to the house? I know it's probably hard to tell unless you were here to take a look at it but any help/knowledge you can give would be appreciated so I don't go in blind/get taken advantage of.

 

So from the pictures these look similar to the vinyl windows I have, and you state fogging up, is that between the panes of glass?

Assuming so, that is due to the IGU (insulated Glass Unit) going bad and has nothing to do with the wood rotting. Ive had a few go bad after 10 years!

The best windows in the world will be krap is installed incorrectly, Bay windows by their exterior exposure are notorious for leaks.

The only real solution is to tear into the trim around the window, add proper sealing and flashing!

 

There are quite a few things going on in your photos. And realistically we are only getting half of the picture by only seeing the inside and not the outside. But having installed vinyl windows every day for the first 20 or so years of my carpentry career I think I can give you a pretty good idea of what's going on there.

First off, the sides of your windows do not appear to have any sort of interior stops that completely cover the edges of the window. Maybe the top looks the same. So you are relying completely on the exterior stop and exterior caulk to keep air out. Warm interior air is allowed to circulate around the window and in the winter that creates condensation around the window where you can't see it readily. That is what's rotting out your wood... it's constantly wet from condensation. In the summer it's the reverse... hot humid air outside hitting cold air conditioned air inside.

Another factor... the inside perimeter is not caulked completely and the type of caulk they did use is likely wrong for the application. Another possible factor... the gap they had to caulk along the bottom looks like it is huge. If you are getting mold inside I would suspect a problem with the caulking outside. But no way to prove that theory with no pics.

The drywall cracks at the corners of the stool primarily indicate poor drywalling and plastering, but the cracking is also exaserbated by the moisture from air leakage, mentioned earlier.

Marq's comments about installation are spot on, and poor air sealing is likely the culprit here. Especially if the outside looks as bad as the inside does. This is not a bay window in the sense that most of us think of them... it's a built in bay / box bay/ or walk in bay, which is windows placed in an exterior wall where the exterior wall and foundation are in the shape of either a box or a bay. These are not more prone to leak than any other window is.

And no, your problems have nothing to do with the double pane IGU's fogging up. But I have seen houses with high humidity that are literally running with water in the wintertime... (I'm talking about water on the interior surface of the glass, not fogged up in between- that is a separate issue) ruining window sills and trim, and if that is the case here then that is a humidity problem that you need to control. IGU's can be replaced if you want to restore the appearance of the window, but that won't solve the issues you mention. I won't get into that here as its a separate issue. Any glass house can do that for you if you want.

My suggestion based on your pictures thus far would be to have a carpenter come and replace the window stools in front of all the windows. When he has the stool off, have him caulk the window to the sill before he puts the new stool on. I use only OSI Quad on vinyl windows... it is least likely to ever crack or let go. Very few caulk stick reliably to vinyl, but Quad does. Also caulk the interior perimeters of the windows and then add an interior perimeter stop onto the top and sides of each window. This could be a profile like a door stop or base shoe. The stop will cover up the caulk and will look clean- not messy or goopy like your stool currently does.

The cracks in the drywall probably say more about how the drywall was hung originally, or maybe that area has rotted out in the past and has already been repaired several times - who knows. Drywall returns and vinyl windows don't mix very well, the joint always cracks unless you do it like I mentioned in the previous paragraph. To repair the cracks at the ends of the stool, I would probably chisel out the cracked parts and first patch them with a setting compound (followed by joint compound) because setting compound is much harder and less prone to crack or absorb water... so that would be a more durable repair.

And then outside, I would assume the exterior might also be in need of new exterior trim / stops, better caulk, etc... similar to how the interior should be done. (Not just gooped up with even more caulk on top of already bad caulk). Can't comment on the sill expanders underneath the window without seeing them, but it's possible the gap under the window was not insulated... pretty hard to fix that one without some skill and experience on a metal brake.

 

First thank you both for your comments. I especially like how in depth you went as that really helped me. Please see my comments below in bold and thank you for your patience in dealing with a newbie. I'd rather become educated than go in blind.

Another factor... the inside perimeter is not caulked completely and the type of caulk they did use is likely wrong for the application. Another possible factor... the gap they had to caulk along the bottom looks like it is huge. If you are getting mold inside I would suspect a problem with the caulking outside. But no way to prove that theory with no pics.

I haven't seen any mold. But you are correct with the gap. When I first noticed the problem, especially with that middle picture, I saw that the gap was very wide. The other two windows it narrows but this had a very wide gap like they just caulked over where the wood was damaged. The other windows in the house have a very narrow gap.

The drywall cracks at the corners of the stool primarily indicate poor drywalling and plastering, but the cracking is also exaserbated by the moisture from air leakage, mentioned earlier.

Marq's comments about installation are spot on, and poor air sealing is likely the culprit here. Especially if the outside looks as bad as the inside does. This is not a bay window in the sense that most of us think of them... it's a built in bay / box bay/ or walk in bay, which is windows placed in an exterior wall where the exterior wall and foundation are in the shape of either a box or a bay. These are not more prone to leak than any other window is.

You are correct. This is not your typical bay window. It's a walk in box. (Picture below for reference)


And no, your problems have nothing to do with the double pane IGU's fogging up. But I have seen houses with high humidity that are literally running with water in the wintertime... (I'm talking about water on the interior surface of the glass, not fogged up in between- that is a separate issue) ruining window sills and trim, and if that is the case here then that is a humidity problem that you need to control. IGU's can be replaced if you want to restore the appearance of the window, but that won't solve the issues you mention. I won't get into that here as its a separate issue. Any glass house can do that for you if you want.

I have not seen the windows wet on the interior but I will continue to look for that in the future, especially now that winter is on its way.

My suggestion based on your pictures thus far would be to have a carpenter come and replace the window stools in front of all the windows. When he has the stool off, have him caulk the window to the sill before he puts the new stool on. I use only OSI Quad on vinyl windows... it is least likely to ever crack or let go. Very few caulk stick reliably to vinyl, but Quad does. Also caulk the interior perimeters of the windows and then add an interior perimeter stop onto the top and sides of each window. This could be a profile like a door stop or base shoe. The stop will cover up the caulk and will look clean- not messy or goopy like your stool currently does.

So removing the stool reveals the actual window sill? It looks like I was assuming what was visible, the stool, was actually the window sill. So from my understanding of your post, I will have him remove the stool, caulk the sill with the OSI Quad (the sill is only at the bottom?), replace the stool, caulk around the window including the window to the stool with OSI Quad. Correct? And as far as stop goes, it's a three window box so the stop would be one piece up the sides against the drywall and window and one piece along the top against the window and drywall correct? I see what a base shoe is, basically what I think of that goes between hardwood floors and baseboard molding to cover up the space there, but you mentioned adding it to the top and the sides, but why not the bottom? And does the base shoe get affixed to the drywall and the actual window with an adhesive? (Believe me I'm not doing this myself, just trying to understand.)

The cracks in the drywall probably say more about how the drywall was hung originally, or maybe that area has rotted out in the past and has already been repaired several times - who knows. Drywall returns and vinyl windows don't mix very well, the joint always cracks unless you do it like I mentioned in the previous paragraph. To repair the cracks at the ends of the stool, I would probably chisel out the cracked parts and first patch them with a setting compound (followed by joint compound) because setting compound is much harder and less prone to crack or absorb water... so that would be a more durable repair.

The cracking doesn't bother me. The cracking doesn't look like it has gotten any worse in three years that I have lived here and this area is blocked by a curtain. If it does not bother me, should I still repair it?

And then outside, I would assume the exterior might also be in need of new exterior trim / stops, better caulk, etc... similar to how the interior should be done. (Not just gooped up with even more caulk on top of already bad caulk). Can't comment on the sill expanders underneath the window without seeing them, but it's possible the gap under the window was not insulated... pretty hard to fix that one without some skill and experience on a metal brake.

I'd like to take more pictures if you would give more advice. What pictures of the outside would you need? I know I can't get a picture of underneath the window since the stool is covering it. I also posted a picture below. Each corner of the windows has this brown looking powder like substance in the corner. The small water stains that were appearing on the window stool were also brown as if the water was leaking out of this brown corner though I've never seen sitting water there. Not sure what it is but figured I would post that picture too. Thanks again! I really appreciate it!

 

Bump...XSleeper see my post above

 

Sorry, when I see a lengthy post I tend to ignore it. That's somewhat ironic.

You don't need baseshoe on the bottom because the stool covers the caulk. If you want it on all 4 sides, that's up to you, but it's unecessary. You fasten the baseshoe with brad nails or trim nails, just like you fasten the stool to the sill. Painters caulk on the wall edge and paint. Personally I do not caulk any trim to the window. They are different colors, so the seam between the trim and the vinyl window gives you a perfect line to cut along with your paint brush or paint shield.

Yes.

I'm not going to make you do it, if that's what you're asking.

Don't know what the brown powder is but I'm guessing that dirty water sitting under the window somehow leaked in through a crack. Maybe it was wind driven rain. Open your windows and wash the sills, make sure they are clean. You might need to remove screens to get those sills clean.

 

Ha! I'm the same way about long posts

Thanks again for all of the information!