what is the proper way to flash traditional windows with peel and stick?

[gerretw]

I have to install some wood sash and frame traditional windows and I would like to use the Typar building wrap. Of course, to maintain their warrentee, I have to use their flashing products. Tyvec makes a double sided peel and stick flashing, you stick one side to the side of the window frame - the opposite (after bending the flashing into an "L") you can stick to the plywood. I went to the Typar site, but it is woefully lacking in details of how to flash a traditional window using their product line.

Does anyone have any suggestions how best to do this? I am going to be installing Hardie lap siding.

Thanks,

Gerret

[charles]

Of course, to maintain their warrentee, I have to use their flashing products.

Typar and Tyvec are made by different companies.

[gerretw]

Yes, I understand that. The point is Tyvek has a method of using their double sided peel and stick to create a flange to flash a wood -non -flanged window. Typar does not have a similar double sided product. So how does one flash a traditional wood window with a one sided peel and stick product, such as Typar makes ( Or Protecto wrap for that matter?) - I can't seem to think of a good way to do it.

I would prefer to use the Typar since I like their WMB better than Tyvek.

G

[Zak S.]

Can you be more clear about what you mean by traditional wood windows? When you say that, I imagine a window with blind stop that is set flush with sheathing. Not something that is done much anymore. If you mean a normal wood jambed window with no nailing flange, the way that I've done it in the past is to cut adhesive flashing down to about 4" wide, peel the backing off of half of it, and install it on the window, covering the outside 2" of jamb. When the window is installed, fold the flashing out over the sheathing, and stick another strip of flashing over the first flashing and onto the sheathing. So you'll have a 2" strip of double thickness flashing stuck together, with an outer strip of the flashing stuck to the sheathing or building membrane. Depending on the exposure of the window, i might do that or I might do something like easy-seal adhered to the window, and then sikaflexed to the sheathing on the sides, and the above detail on the top.

[Bill Robinson]

I will try to get the time tomorrow to do a little demo video to show you how to do it.

[TSJHD1]

I just had to put new exterior casings on existing windows. The siding was entirely removed also (house got new vinyl). I used the p&s tape, and lapped it right onto the jambs. Then we used new PVC brickmold and sill material to trim the window, with a metal head flashing installed per Tyvek's instructions.

So if replacing the exterior trim might be an option, this method makes the flashing details pretty simple.

Tom

[gerretw]

It is a new room addition, but in a historical district, so we have to make it look original - meaning wood double hung windows, true divided lights, and though the existing house has wood siding, we are using Hardie Plank spaced to match the existing. So, it is a new installation - I just want an installation that won't leak. Homey don't like to do comebacks.

Zac's idea is pretty neat. In the old days we would just staple the flashing paper to the jamb, and nail on the casing over it. The peel and stick is too thick to make that work.

G

[TSJHD1]

In the old days we would just staple the flashing paper to the jamb, and nail on the casing over it. The peel and stick is too thick to make that work.

G

I don't know why you say that; If one layer of p&s will work, then how can one more layer cause it not to?

Tom

[gerretw]

Here is a sketch of what I believe you are suggesting. So basically the peel and stick is adheuring to 1/2" of jamb material. I guess it is ok. The problem is, other than Tyvek, the manufacturs don't give details on how to do non-flange windows. I would do the Tyvek system, however it is hunderds of $ worth of special order flashing that I didn't budget for.

G

[Allan Edwards]

I really don't see the point in covering the jamb edge partially with membrane. I would put the Tyvek on and wrap it into the frame on all 4 sides, then membrane over the Tyvek wrapping into the frame and covering the frame on 4 sides. I would do this after I did some sort of pan and of course head flashing, I would back prime the jambs, shim the window up 1/4" or so off of the pan in case water sits in the pan, and call it a day.

[gerretw]

Why not wrap 3 sides: the top and 2 sides, leaving the bottom open so it will drain into the pan and out?

Do you realize these wood windows have a redwood sill? They have those metal corner flashings stapled to the 2 bottom corners. I am not so sure about taping the bottom.

What is weird, is the pan drains behind the siding if you use the flex wrap to make the pan. How good can that be? Yet that is the way it is shown on their web sites.
G

[Allan Edwards]

I instruct my carpenters to wrap all 4 sides as a precaution, I want the interior of the framed opening protected. But the real protection in my opinion comes from a pan with an exit path, and while a pre-formed metal or even PVC pan is the best, we sometimes do them out of membrane with a back-dam piece, preferably with a sloped framed sill. I do like the Tyvek wrap because it creases in the corners, but yes it is expensive. And we do drain behind the cladding.

[gerretw]

When you say you wrap the frame are you referring to the window jambs or the trimmers and header?

[Allan Edwards]

When you say you wrap the frame are you referring to the window jambs or the trimmers and header?

I am referring to the frame, not the window jambs.

[steve demetrick]

What is weird, is the pan drains behind the siding if you use the flex wrap to make the pan. How good can that be? Yet that is the way it is shown on their web sites.
G

I tuck the second to the last course of siding (clapboard) or the third from the last course of siding (shingles) under the pan so that the water in directed over the siding. If the pan isn't wide enough to reach that point I'll cut a width of tar paper and tuck it under the pan and tuck the siding under the tar paper. This detail is most important under the vertical seam between the siding and the casing.

-Steve