Window Flashing replaced?

Hi all,

Is this replacing window tape flashing? Thanks

It looks like some caulk smeared over the nail fins, to me.


Looks a lot like drywall mud. Also the bottom of the nail flange should always be left open to allow for any water that does get in there to drain out. The top, and sides should be taped, not smeared with some sort of mastic, glue, or caulking. They need to always follow the window manufacturer instructions. Just look them up.


Looks like mastic to me.

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Liquid flashings are available. Huber Engineered Woods (Zip System) makes one such product you can view here . This appears to be either a new build or major remodel. To determine if it is an acceptable flashing material you would need to consult the window and wall sheathing manufacturer requirements as well as any Code approvals by ICC and/or the AHJ.

Before you can verify that you need to know what was used and obviously there will be no markings on the material used. Therefore this is a good example of making an appropriate comment in your report to have the Builder/Contractor display what materials were used and the approvals for that material.


Makes sense. Thank you. House next door has same windows with tape flashing. I’m deferring to professional at this point

No flashing at the window sill:


This is what it should look like.


Window frame nailing fin, looks like nylon with, what looks like Liquid Waterproof Sealant.
Not the right way to flash a window and fenestration.


good catch


You are suppose to be the professional at this point. Also is your client on a new build now suppose to hire a second person to inspect just this condition?

Also as another item, and reason to pull the window manufacturer installation requirements, are the possible missing fasteners at the window fin corner(s). Some specifically require them at the corners and others are not specific about that. Was that covered in the report as needed by the window manufacturer installation requirements?


Liquid applied sealants have been around for decades. This is an acceptable replacement for tape and becoming more popular because tape can be, and often is, incorrectly installed.


Fluid applied flashing. Which is fine when applied properly; in this case, it is not. The builder likely selected this method because of the sheathing/wrb system.


Here’s a video on the Zip system liquid applied flashing.

I’m mixed on this system. So many builders screw up conventional flashing and it’s hard to inspect because of the layering. Yet every “50 year” caulk I have looked at after a decade or so is old cracked and hard. I’m skeptical of the lifetime claims of the liquid systems, and in my area 50 years is a young house… are we supposed to throw them away so soon?

And, mistakes in the liquid system are similarly hard to find, as it’s impossible to inspect “later”. If there’s a gap in the sections covered by the window flange you won’t know until decades later.


I think we are all skeptical about a system where the bottom of the window is sealed.