Vapor barrier

[mclark]

Class 1 0r 2 Vapor barrier required. Currently Poly vapor barrier installed but it must meet 2018 IBC 720.2
We are Zone 5 Exterior walls. Used to be a old restaurant and now a bank. Has anyone heard of a paint that can be used for a barrier? Inspector wasnt helpful on this, Also said a Kraft faced Fiberglass that is more than 0.1 less than1.0

 

[khsmith55]

If the vapor barrier is covered then no requirements (720.2.1).

 

[walker.t]

Class 1 0r 2 Vapor barrier required. Currently Poly vapor barrier installed but it must meet 2018 IBC 720.2

Is there something wrong with the poly vapor retarder you have to make you think you need something else, IBC 1404.3.3 says that sheet polyethylene has a Class I rating.

I’m confused by how you cite a provision regarding insulation but are otherwise talking about vapor retarders, vapor retarders are addressed in IBC 1404.3 (Vapor Retarders.)

Has anyone heard of a paint that can be used for a barrier?

Here’s an article with a list of several low permeability paints:

https://www.jlconline.com/how-to/exteriors/q-a-vapor-retarder-paints_o

 

[Yankee Chronicler]

Answers: Moisture / Vapor Retarder Primer Paints - GreenBuildingAdvisor

Hi everyone, I did some research and found these paints that are qualified as moisture / vapour barriers: (The table shows the grams of VOC per litre, Brand, Model #, and coverage.) under 50g/l -- Kelly-Moore -- 95-500TDS - 250-300sqft-gal - <1 perm 73 g/l -- Miller Paint -- Vapor-Lok...

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