Hello:

Before I continue, I thought that I should get the answer to this question:

Should the Tyvec be placed over the 2" Roxul ComfortBoard IS or should it be placed under this insulation, between it and the OSB sheathing.

Boy, I sure hope that it should be placed over the insulation 'cause I just completed my 46' x 9' wall that way!

Thanks for your help.

Rob.

The placement of the Tyvek depends on how you are mounting and flashing the windows & doors.

An "outie" window installation will have the window's exterior glass on nearly the same plane as the siding, and the flashing would extend to the exterior side of the rigid rock wool, in which case the Tyvek has to be exterior to the ComfortBoard to lap properly with the flashing.

An "innie" window installation puts the glass nearer the plane of the OSB, in which case the Tyvek has to go between the ComfortBoard and the OSB to lap properly with the flashing.

Hi Dana1, thanks for responding to my post. :)

The details on my windows are as follows:

The casement windows have a nailing flange on the outside to attach the window to the 1x4 strapping that runs around the perimeter of the rough opening. The outside glass is set back from this flange about 1 1/2". This means that the glass is 3/4" into the 2" Roxul because the strapping is 3/4" thick. This means that the glass is 1 1/4" beyond the OSB. The window frame was ordered to come flush with the sheetrock, which is attached to 1x4 strapping on the 2x6 studs - this means that the inside glass, of the triple glazed windows, is about 6 3/4" in from sheetrock.

There is a "J" channel on the outside of the window into which the horizontal siding slides to cover the nailing flange.

Before I installed the 2" Roxul, I sealed the OSB joint around the R/O 2x6's with RESISTO RED ZONE WATERPROOFING TAPE (4-in-wide).

At present, the Tyvec is on top of the 2" Roxul, under the siding strapping.

I have only on wall done so far so I guess that I could redo it, if need be.

I have not yet installed any windows.

Your opinion would be truly appreciated.

Rob.

Rob - the important thing is that if you run water against the house wrap at the top of the wall before installing the siding, the water will always be force to the outside and never allowed to get behind flashings. as per Dana's "to lap properly with the flashing". On the way down, the house wrap always goes over the flashing. If the flashing is applied after the wrap the water gets in behind and causes trouble.

Thanks all! :)

Rob.