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Community and Q&A

Flashing Tape Over Felt Paper

ssbdamion | Posted in General Questions on

Hi all, I have an odd situation to present. My house is a 70’s house with the exterior wall comprising of a single layer of felt paper, and stucco. There is no sheathing and the house in in Southern California climate zone 3. I had a shower redone and noticed after demo that the south facing felt paper wasn’t in great shape, but there were no signs of constant leaking, and if there was, it dried since it doesn’t rain much here.  My contractor said he would do something about it before the shower was redone. I didn’t think much of it, but looking back I realize that he used flashing tape to cover the felt paper. This seems odd since there is now a vapor barrier on the felt paper and I’m looking for advice on how much of an issue this may cause. Replacing the stucco from the outside will be a major project since the stucco is considered the shear wall and all the demo will likely ruin the waterproofing of the new shower that is now installed. The shower walls were waterproofed using felt paper and floating the walls, which is fairly standard in Southern California.  I’ve attached photos and looking for advice on how serious of an issue this may be and if/how I should act to fix it?

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  1. Steve Knapp CZ 3A Georgia | | #1

    I can't make out the brand from your photos, but I'm not sure this is a big deal (an expert may disagree). ZIP tape is rated at 3 perms, for example, and your tape may have a similar permeability rating.

    FWIW, I would be more concerned about keeping bulk water out of the wall cavity. If your contractor is using cement board in combination with something like Schluter or Redguard, you are probably fine.

    The only other thing I would look at is bathroom ventilation. You really want a high-quality fan (Panasonic Whisper fans are great) with sufficient CFM to vent moisture to the outdoors. If you have household members who avoid turning on fans, I'd install a motion sensor with an automatic timer to avoid issues over the long term.

  2. ssbdamion | | #2

    Steve, thank you for the reply. The flashing tape is Fortiflash and per the spec sheet it says it has a perm rating of less than 0.1. Regarding the bathroom fan, that has not been installed yet but it will be a panasonic, broan, or fantech which will exhaust out the roof and I will have a timer or sensor installed.

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