Flashing old windows in new costruction wall- no nailing flange

[joseph moore]

I have a question that I'm hoping some of you have experience with. The back wall of my 100 year old house was in bad shape....sagging with a rotted corner post etc. It had novelty style drop siding(shiplap joint) on it with no sheathing whatsoever. It was just siding nailed directly to the balloon frame with heavy rosin paper in between. Since many changes were being made to the wall ( a window where there used to be a door for a 2nd floor egress, a door where there used to be a window on the 1st floor , a larger kitchen window etc.) I decided to add sheathing to the wall.... 1/2 OSB ( for strength and also so I could re-wrap it more easily).
I pretty much ended up reframing the entire thing by the time I had repaired the existing framing and made the changes I needed to make for the openings. I will be wrapping it in Tyvek later this afternoon.
So....my question is this. The windows and doors that I'm putting in are all wood frame. The 2nd floor windows (3 of them) are all old style double hung 6 over 6. The patio doors are Marvin but have no nailing flange and the kitchen window is this weird awning window (it tilts out from the bottom) also with a wooden jamb and no fins/flanges.
What is the best way to flash these? Adding fins/flanges is out of the question as I am already too far behind schedule with winter approaching and 3 other sides of the house that need my attention. There is a lot of info on the web regarding new windows in old houses but this is the opposite.....and perhaps it's a unique situation. Who on earth would want to use those old windows when everything else is shiny and new? Well, I guess I would.
Anyway......the best two methods that I've seen in my web searches are either-

1) stapling tar paper strips over the edge of the rough opening, with the head flashing lapping the side flashings, applying caulk to the tar paper, then installing the casings embedded in the caulk. I believe this is sort of the old school approach and it sounds easy....which would be great
2) another approach which I've seen with a few variations ( including a Dupont PDF on flashing fin-less windows) is......using a peel and stick membrane doubled back on itself in some complicated way, then applying the casing. I don't really understand this method and am not sure it's the way to go. At the same time I am already going to be using peel and stick flashing on the rough sill so I will have that material on hand (protecto wrap)

So does anyone have any experience with this? It seems like wooden windows were being installed in wood frame houses for a lot of years before modern technology changed the game. I can't imagine that they always leaked. There's got to be a simple way of doing it, right? And if so, such as with the tar paper strips described above, what happens with the house wrap? Does it wrap in to the R.O. on the sides? Or does it get trimmed flush? I figure whatever I do is going to be worth the 1/2 hour or so per window that it will be. I just want it not to leak and I also don't want to alter the window jambs.
Sorry for the long post....just trying to describe the situation in as much detail as I can. Any advice is most appreciated. Thanks

[Tom M King]

There are a number of adhesive tapes for this purpose now, instead of using tar paper. They are fairly new, and only have a ten year warranty, as far as the stuff I used this morning, but I have a lot more confidence in them than tar paper. Fine Homebuilding had a good article in the last issue on installing some European windows with the newer flashing tape. It would probably be worth you finding that issue. You can buy the window tape in Lowes and Home Depot even.

I just sealed everything with the tape, but didn't let it come out far enough on the jambs to be shown after the casing was nailed on. After a coat of paint, caulking sealed the little crack caused by the tape thickness. Low expansion foam around the jamb after the install is complete on the outside.

[Peter Quinn]

I installed an in swing french casement in my garage remodel of my own construction, solid wood, no nailing flange. My approach was to factory apply the casing using elastomeric caulking and trim head screws, it's the best nailing flange you can make. So windows go in with casing applied, siding butts hard to the windows, caulk those seems with same high quality elastomeric caulk, best protection you can get. I flashed the openings using flexible membrane, the sill rough sill was beveled down and out with a piece of FJ cedar clabboard (dirt cheap), I got these plastic corner protectors from Amazon so I could use a cheaper peal and stick membrane, the super flexible Dow stuff is great but terribly expensive for the privilege of having seamless corners. It's all about water shed. My garage/barn was sided with shiplap on 10mm rainbattens from Dow over tyvec to create a full rain screen. Tyvec wraps the rough openings to the inside, essentially a flashing pan is created working from rough sill up, precased window goes in.....rain stays out. My large window is on the side of the building hit by the prevailing winds, I've stood there in a driving rain, interior walls are still open for perfect visibility, no leaks. Most important thing is a good cap flashing with a drip hem if possible, this alone diverts 80% of the water away from your windows.

Forgot to mention the tyvec at the head gets cut back and held up out of the way, flash the sill, flash the sides, pull down the tyvec over the sides to create a path down and never behind using the layers, then tape the corners and flash the head. The cap flashing has to go behind the tyvec too so careful where you put the tape if using. I had 4" casing so the flashing was higher than the tape at the rough opening. With a basic brick mold they might interact.

[Tom M King]

I'm not sure that the way windows have been mounted for at least a century was something that really needed improving, other than for air infiltration, but foam has taken care of that for a long time now. I was in a house I was building when a small tornado hit it. It had Anderson double hung windows, with nothing special about the way they were put in. This was in the early '80s.

After the tornado passed, which included rain, there was no evidence of any water getting behind anything. One place it did come in was around the sash. A perfect outline of each sash, on the windward side, was highlighted by horizontal solid water coming in around every sash on that side of the house, into the house for about 20 feet. There were doors open on the opposite side of the house under a porch. They were the tilt-in windows.

This house had a large stone chimney open all around in the great room. I went and stood on the lee side of the chimney, thinking the house might come apart. No damage was done to amount to anything. The windward side was completely plastered with about an inch and a half of green leaf bits, and some shingles were gone.

The tornado twisted off the tops of about half of the trees all around, but they have since all filled back out.

In any case, that house is still fine, with nothing fancy for window installs through that. I think that was even before Tyvek.

I always built houses with generous overhangs though. The ones I see with the most trouble, are on walls with little to no overhang on the roof.

That house had White Oak siding put on with nailgun nails, and it didn't suffer a bit after we powerwashed the leaf bits off of it.

[Walter Plummer]

We just nailed through the brick mold (casing) to set the windows then added shims between the rough opening and the window inside. You can get pre-bent aluminum zee flashing for the tops of the windows at any home center or lumber yard. I have not used the tape but I think you would do the sill first then the sides, set the window and flashing and tape over it to the house wrap. Caulk which ever siding you use to the brick mold and paint the windows. Hope this helps. Good luck.

[Brian W Smith]

Oh my,Joseph....didn't even read one response and was thinking,dang.....what participation.Sorry for sounding like a dad,you need to thank these folks,am sure you are/will.Good stuff.

[joseph moore]

Hmm.....I'm pretty sure I said in my original post that I was going to be working on the house this afternoon. My house may be a construction zone but I don't think I want to drag my iMac out onto the scaffold.

[joseph moore]

Thanks for the reply. I looked for the article you mentioned but didn't have much time so I'll search some more. I like the Taunton press publications a lot....I'm sure the article will prove to be informative. I thought about doing something similar as far as lapping the flashing onto the jamb prior to installing the casing. I figured if the tape pushed the casing too far out I could always rabbet the casing . But you're right....caulk would probably fill that just fine. The 2nd story windows (the really old ones) actually have an interesting detail.....the outside stop is a 2 inch wide piece that caps the jamb instead of it just being a small strip nailed to the inside of the jamb. In other words- the jamb is not as deep as the cavity. Instead, the stop, capping it like a "T" brings it out to the sheathing. So that's even more surface area to lap the membrane onto.

[joseph moore]

Thanks for the reply. First of all, what's a "drip hem"? I am planning on using Azek or similar drip cap over the head casing with a metal z flashing over the drip cap and under the Tyvek. I also am planning on using a piece of beveled siding to slope the rough sill.
And also like you, although I didn't mention it in my post, I am planning on creating a rain screen with strips of 1/4 inch ply. I know that seems like not a lot but I don't want to bump the wall too far out. I might consider 3/8 inch. Just got it Tyveked today so I need to make a decision soon.
It sounds like a good idea with the pre-application of the casings. Did you caulk the jamb prior to screwing the casings into it? That was the only part I was unclear on.
As far as the rain screen strips....did you just use wider ones around the windows so that they could act as nailers for the window casings as well as the ends of siding butting into the casings? That seems like the simplest way to do it but I don't know if it creates a problem with the drainage. Also did you use the flexible membrane under or over the rain screen strips that surrounded the window? Lots of questions I know. I get a little obsessive with this stuff. Thanks again.

[joseph moore]

Good story. That wasn't in NC though was it?

[joseph moore]

Thanks. There's no brick mold on any of these windows/doors but Peter's idea of pre-applying the casing would result in a similar scenario. Definitely might be the way to go.

[Peter Quinn]

Thanks for the reply. First of all, what's a "drip hem"? I am planning on using Azek or similar drip cap over the head casing with a metal z flashing over the drip cap and under the Tyvek. I also am planning on using a piece of beveled siding to slope the rough sill.
And also like you, although I didn't mention it in my post, I am planning on creating a rain screen with strips of 1/4 inch ply. I know that seems like not a lot but I don't want to bump the wall too far out. I might consider 3/8 inch. Just got it Tyveked today so I need to make a decision soon.
It sounds like a good idea with the pre-application of the casings. Did you caulk the jamb prior to screwing the casings into it? That was the only part I was unclear on.
As far as the rain screen strips....did you just use wider ones around the windows so that they could act as nailers for the window casings as well as the ends of siding butting into the casings? That seems like the simplest way to do it but I don't know if it creates a problem with the drainage. Also did you use the flexible membrane under or over the rain screen strips that surrounded the window? Lots of questions I know. I get a little obsessive with this stuff. Thanks again.

I bent my own copper caps, had a friend help who is good with a brake, he put a hem, or extra bend at the bottom, then flared this out just a bit, like the last half inch of a piece of drip edge molding. A lot of the aluminum Z flashing I looked at had no such detail, this hem&flare sheds water much better. Instead of rolling down the exterior trim it just falls off at the head.

[Jim Andrew]

Good quality caulk is your friend. The sill on the wood windows should still be attached, as it is one piece which extends to the outside. The casing fits on top of the sill, and goes around both sides and the top. Caulk every surface the casing touches of the window frame. After you put the window units in, put head flashing over the top of the casing. Caulk between the window and the head flashing. As you install the siding, caulk between the siding and the window casing, and after you get done with siding go back over the window with the caulk. That way you have the caulk between and on the outer edge of the siding. Have never used the tape, but sounds like a good idea. And the way housewrap was installed, it was cut out of the window opening but lapped into the opening and stapled on the sides. And under the window.

[joseph moore]

Thanks. I believe the drip cap I'm going to use has a groove in it to keep the water from running horizontally back to the head casing. So that's a similar idea. But yeah.... I'm sure the custom copper looks way better than the aluminum z flashings.

[joseph moore]

Sounds good. Thanks for the response.