Helpful? 0

Window flashing with exterior rigid insulation

I operate in climate zone 5B which has about 6,600 HDD. Homes built here generally do not require cooling systems -- only heating. My question has to do with where the water resistive barrier should be placed on the construction detailed below:

Form the inside out:
1. 1/2" sheetrock
2. 2x6 framing filled with dense-packed cellulose insulation
3. 7/16" OSB sheathing
4. 2" XPS rigid insualation
5. Jumbo Tex-type WRB -- bassically 2 layers of 15# impregnated roofing felt
6. Stucco wire
7. 3-coat stucco system

My thinking is that the flashing, particularly the bottom window flashing, should extend from the window nailing fins over the 2" XPS rigid insulation and then down between the two layers of Jumbo Tex WRB. My thinking is that the 1st layer of the Jumbo Tex bonds to the back of the stucco system so any moisture should be allowed to run down between the 2 layers of Jumbo Tex.

Is that right?

Asked by Steve Vollstedt
Posted Thu, 02/03/2011 - 16:14
Edited Thu, 02/03/2011 - 16:38

Tags:

2 Answers

Select your preferred way to display the comments and click "Save settings" to activate your changes.
1.
Helpful? 0

Hi Steve,
Why wouldn't you extend flashing out beyond the stucco? There may be a good reason.. but I can't come up with one.
Cheers.

Answered by Chris Koehn
Posted Thu, 02/03/2011 - 16:36

2.
Helpful? 0

Steve,
You can install your windows as "innie" windows or "outie" windows. (If you are unfamiliar with those terms, see ‘Innie’ Windows or ‘Outie’ Windows?)

If you want to install your WRB on the outside of the rigid foam, I suggest that you install your windows as outies.

Answered by Martin Holladay, GBA Advisor
Posted Thu, 02/03/2011 - 16:37

Other Questions in Plans Review

The differences between mass and insulation

In Green products and materials | Asked by Nathaniel G | Sep 15, 14

Most cost-effective method for achieving 3 ACH 50?

In Green building techniques | Asked by Nick Sisler | Sep 17, 14

Tudor half-timber battens and exterior stucco — rainscreen assembly

In General questions | Asked by Ani Brown | Sep 17, 14

Has the Oak Ridge study on convective heat loss in blown fiberglass been updated to cover newer materials?

In Energy efficiency and durability | Asked by Neil Weinstock | Jul 21, 14

Liability insurance - what would that cover?

In General questions | Asked by George G | Sep 12, 14
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!