Flashing windows without sheathing???

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gordo

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Does anyone have any experience or suggestions on how to flash a nail-flange window when there is no sheathing?

I am replacing 3 windows in our house that was built in 1906. The clapboard is nailed directly to the studs (it's not overlapping clapboard, just tongue-and-groove).

All I can come up with that sounds moderately reasonable is to somehow shimmy some flashing between the siding and studs at the sides and the header and then nail the flange to the studs with a generous bead of caulk on the backside of the flange. Then I'd put some flashing tape on top of the flange, but I wouldn't be able to tuck the tape under the siding like I "might" be able to with the flashing. Not sure if that defeats the purpose though, and I haven't completely figured out how to flash the sill so that any water doesn't leak down in the inside of the siding, but I'm kicking around a few ideas on that :think:

I'll be installing the trim butted up to the window frame to cover the flange and the gap between the window and the siding and applying more caulk to hopefully get a good seal between the trim and window, and between the trim and the siding.

This isn't really ideal, but I can't really think of any other way to get it done besides ripping off siding and trying to put it back the way I found it. I'm pretty sure that would make things worse!

Any thoughts?
 
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metalfisher76

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Sounds like yer on it? Prolly throw a bead on after window goes in and before ya start trimmin `er out too??? I`d say stay away from rippin off siding too. But I haven`t seen what ya got goin. Got any pics? What kinda siding?
 
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OnTheFly

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I replaced all of my windows the summer before last. I have T-1-11 siding. I replaced aluminum frame with vinyl windows and, with help from a buddy who does this for a living, it was not hard at all. Get some pictures for metalfisher and I to look at then we'll talk some more.
 
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gordo

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I can get some pics up soon. The exterior is all still intact since I don't get the windows delivered for another 4 weeks or so. I did pull OFF the interior trim to get some measurements and a better look inside - that's how I discovered no sheathing.
As of now, yea, liberal beads of caulk are in the plan unless I can figure something else out!
 
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capblack

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i dont think there is any flashing needed. use tar tape around the frame and then a generous bead of caulk before the window goes on. then nail it, and seal the flange with more caulking, install your trim boards, and then caulk the trim boards. if that leaks, you need a different brand of caulking. be sure to use some silicone based that is designed to stretch (wont crack) or vulkum (spelling?) might work best.
 
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OnTheFly

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The new window can be nailed directly onto the cripples. Cut back the siding just enough to get the window in. The frame work should be square already but it wouldn't be a bad idea to run a level on it. The new window can now be placed in the opening, shimmed level at the bottom and nailed preferably with Tico (tea-co) nails directly onto the framing. Do not nail the top flange to the header. Only nail sides and bottom. Bullnose molding goes on next. Hold a piece of material against the window frame and trace around the frame. Now take your Skill saw and cut ON the line. This will allow room for the molding plus the bead of calking that will seal it all up. Use Velkum like Capblack suggested. The siding should look perfect around the window. Paint or stain the siding and you're done!
 
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gordo

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Great, thanks for the suggestions!
I'm glad it's not totally unreasonable - I can handle this. It will take a few weeks until I get this completed, but I'll be sure to take a few pictures of the process and let you know what my overall process ended up being.

Thanks again!
 
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metalfisher76

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The new window can be nailed directly onto the cripples. Cut back the siding just enough to get the window in. The frame work should be square already but it wouldn't be a bad idea to run a level on it. The new window can now be placed in the opening, shimmed level at the bottom and nailed preferably with Tico (tea-co) nails directly onto the framing. Do not nail the top flange to the header. Only nail sides and bottom. Bullnose molding goes on next. Hold a piece of material against the window frame and trace around the frame. Now take your Skill saw and cut ON the line. This will allow room for the molding plus the bead of calking that will seal it all up. Use Velkum like Capblack suggested. The siding should look perfect around the window. Paint or stain the siding and you're done!

Yup! That`ll do it....

Although if ya got yerself a good easterly blowin.... The flashing and extra caulking are not gonna hurt. Fact is a lot of problems are still coming up these days. It`s always the ol` "the weather is worse here" or "no, your guys just suck at this" argument. Rain+wind=bad things.
 
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todd_brooks

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You know what they say theres more than one way to skin a cat. In most cases where there is no sheeting like with T111 a lot of guys will cut the flanges off. You do this by scoring the flange on both sides several times and bending it back and forth until it pops off. You then use screws from the inside to secure the window frame. 4 should do it unless their over sized. There are stop blocks at the top of the window frame if it an operator. That you can pop or slide down out of the way to hide your screw under. The lower screws can be put in the track of the lower pain so they will only be seen with the window open if even then. If you caulk your windows well aka get a good injection of caulk in between the siding and window frame. You're good to go really its not as good as having a flange granted but this is common practice for retro fit for a lot of folks. If you add trim on top of that for the look you'll want to caulk that to then you'll have two water stops.
I've got a buddy that won't use Valcum any more because he's had it pull away from the vinyl more that a few times. Sidewinder one you could use but you might check to see what the manufacture recommends.
If you can figure out a way to pry up the siding at the top enough to leave the top flange on the window and slide it under you'd do well to do so. As thats the weakest link.
The other option is to do what was already suggested and cut back the siding, attach your flanges to the frame work( use screws so you can adjust for square if need be). And trim using a piece of Z-metal at the top that goes over your trim and under your siding.
Keep an eye on your caulking every few years and maintain it nothing last for ever as the say.
O and depending on your windows you may have to cut back your trim on the inside to fit. Thats another story really. Good luck
 
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