Window flashing and WRB

What do you say about it?

Should the WRB be lapped over the top of the window or tucked inside?

The wrap gets tucked around the edges of the opening, then the window (with nail fin) is caulked and installed, then the tape flashing is applied starting at the bottom. Some builders use a separate sill pan flashing on the bottom of the opening as an added precaution.

Tucked at the sides and bottom only, not at the top. Overlapped at the top.


You would be technically correct if installing siding, however most work down here gets another layer of VP which does go over the window fin at the top, then wire lath and stucco.

Also, the OP’s window is under an overhang which protects the top for the most part. Most windows leak at the bottom, unless it is not protected at the top.

Why don’t you look at the fenstration instrucitons for the specific window. Thats really the answer

Actually, he would have to look at the instruction from the WRB manufacturer :smiley:

Yeah, Will. :slight_smile:

Here’s a quick Tyvek video for window installs:

And, here’s a bit longer one that is good, too:

Thanks Larry. As the first video demonstrated how easy it is to properly install window flashing/building wrap it makes you wonder why it’s so often done incorrectly.

Really, isn’t that the truth!..and, your welcome. :slight_smile:

When we first started doing phase inspections, we offered 3 phases (Pre-pour, pre-drywall and final). After about 5 inspections, I decided to add an extra phase which is the WRB inspection, because unfortunately it is more often than not improperly installed.
Most WRB in this area have 2 or 3 page instructions WITH drawings/sketches.
One does not even have to know how to read to understand how to properly install these. Sad but true…
The Houston market is booming, we perform multiple phase inspections a week. Monday we have 2 pre-drywalls and hopefully the builders won’t have covered the WRB yet…

Just took a bunch of photos of that from several homes being rebuilt in the tornado alley. None of them have it right. It drives me crazy. It’s so simple. Everything above should overlap what is below. Keep repeating that to yourself as you build the house.

Thanks everyone. The video illustrated what I’ve always thought was correct. Often times I see the WRB tucked inside all sides and the window flange sealed with tape at all 4 sides.

Yes, the same video for wrb is expressed in the window installation instrucitons for flanged windows. Get some. :smiley: :cool:*&isort=globalpop&method=and&view=grid&cnt=25&af=ttype:doublehung tdoctype:installationguide

I have only seen one builder up here installing windows correctly. All the other will install the windows directly on the osb sheathing and put a layer of self adhering flashing over the nail fin. It will be like that for a month or two until they put the WRB on. By that time all the self stick is flapping in the breeze. With this rainy climate, they leak and leak and leak.