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Concerned About Drywall Product Type

lekawa | Posted in General Questions on

Wondering if anyone can enlighten me regarding drywall types.  My drywall guy just sent his crew out to start hanging today and I didn’t go out there until they were gone for the day (playing it safe due to COVID-19) and when I did, I noticed they used a significant amount of “bright blue” drywall.  At first I thought it must be the “moisture resistant” drywall we agreed would go in the entire bathroom…even though it’s significantly (darker/brighter/more “saturated”?) in color than any drywall I’ve personally seen…but I’m no expert.  I also noticed they’ve used it in “part” of the kitchen, and we didn’t discuss using moisture resistant drywall in the kitchen.  I will get some answers tomorrow, but wanted to pass this by any of you who might be able to help me understand what specifically this is (moisture resistant or not?) and whether the color is normal.  I suppose I’m just a little concerned that it could be some unknown product from China, or somewhere else with a fake “American Gypsum” label.  Is this color normal for American Gypsum wallboard?  I might be over-thinking here, but I know there was a serious problem with Chinese drywall a few years ago, causing health and corrosion problems.  The last thing I’d want is to eventually have to tear this out and start over again.

I don’t see anything on the board or the label on the edge that specifically suggests “moisture resistance”…..nor am I finding any bright blue drywall on American Gypsums website….nor am I able to pull anything up based on the bar code number.  None of this is very confidence inspiring.  Is it possible that this is what is referred to as “pre-decorated” drywall?  Photos posted below for anyone who might be able to decipher whether or not I need be concerned.

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  1. creativedestruction | | #1

    ASTM C 1396 is the spec for moisture resistant gypsum board and tile backer. Its suitable for a bathroom. I've usually just seen green board but I wouldn't be concerned with the color.

  2. Expert Member
    Akos | | #2

    Most likely it is mold resistant drywall. It is fine for bathrooms but should not be used as a substrate for tiles around a tub or shower without a membrane like Kerdi. The stuff you can directly tile over has a fiberglass facer not paper.

  3. lekawa | | #3

    Thanks Jason...I did see that page earlier but the way it reads, it seams to suggest that ASTM C 1396 is a general category that covers multiple types of drywall (when you scroll down) It also refers to "ASTM C1396M" which was kind of making me wonder if the "M" meant "moisture board"...and this doesn't have the "M" on its label....nor do I see anything further on the page about what distiguishes ASTM C1396 from ASTM C1396M :(

    I think I'm just going to have to call American Gypsum in the morning....maybe email a picture....and ask them specifically what it is.

  4. Expert Member
    BILL WICHERS | | #4

    Drywall is usually printed with a product identifier, usually in a strip on the face along the edge of a full sheet. If you have a bunch of cut pieces it might take a while to find, but you should be able to find that info. The printed product information means a lot more than the color.

    I’ve seen white, yellow, purple, blue and green drywall. Best to go with the written info and not the color if you need to know what you have.


  5. lekawa | | #5

    Bill, yes...the photos above show that strip, but the only identifying info is where it mentions ASTM C 1396 Section 5. (which used to be categorized as C36) from what I've been able to gather this evening after looking around, this was standard gypsum wallboard...not moisture resistant...and the ASTM C 1396 is a new "broad category" covering many different types. There is nothing on it indicating moisture resistance...and I believe American Gypsums moisture resistant wallboard is identified with "M-BLOC" on the label.

    I'll know more tomorrow after giving American Gypsum a call, and will post the answer just in case anyone's interested.

    In the mean time, here's a link anyone can check out if you're interested in a better explanation of what ASTM C1396 replaced.

    1. Expert Member
      BILL WICHERS | | #6

      There is usually a printed strip on the actual face of the drywall too near one edge which is the one I was referring to. The strip you pointed out is different (but shows similar info, so probably moot).

      Hopefully you can get some info from the manufacturer when you call.


  6. lekawa | | #7

    I'm beginning to think this guy got this bright blue stuff for nothing and either was "told" it was moisture resistant or knows it's not and figured I wouldn't know the difference. It smells weird as an airport (jet fuel? Kerosene?) It's hard to imagine why else he would have way more of it here on site than we agreed to use, and why he put it in the kitchen when I didn't ask for it there. I'm pretty sure it will take multiple coats of paint to cover the color too. Also realized he didn't use cement backer around the shower as agreed. It never ceases to shock me the petty things people will try and pull off. Looks like another hairy confrontation is in order.

  7. lekawa | | #8

    Ok....I spoke with the technical guy at American Gypsum. He tells me it is, in fact M-Bloc....doesn't know why the end part of the label has been torn off every board (the rest of the drywall here still has their full labels attached. He also explained that drywall is "in very short supply" right now ....and thought that might explain why the drywaller is using more of it than he needed to. I do find it a little "odd" that they would use such a bright color for their moisture resistant board....I've had two people tell me "well you'll need to prime it"... which, of course, I'd need to do anyway, but I believe it will still need either extra primer and/or extra paint to keep the blue from showing through. Wondering now if what makes it moisture resistant is the fact that it such an intolerable blue that just about anyone/everyone would be painting multiple layers of primer and paint over it to cover the color! lol ...Now all I'll need is a boatload of "jet fuel smell-blocking paint" and I'll be good!

    Sorry, I'm getting a little sarcastic, I know......Just soooo tired of this project and can no longer contain it.

    1. BurkeHouse | | #12

      Your tone on these posts hits the nail on the head for how I'm feeling these days! We're starting drywall in a couple weeks and nerves are running high. Just wanted to say you're not alone, haha. Stay vigilant my friend and we can both hope in the end we will forget all the issues from the build and enjoy the house.

      1. lekawa | | #13

        BurkeHouse+ Thanks for the understanding and words of encouragement...I've been telling myself that exact same thing...That I plan to let it all go once it's done (told my sister I'm going to have to burn a LOT of sage to clear the energy first though!) :)

  8. tjanson | | #9

    I like the blue drywall for the contrast with the tape and joint compound. I haven't had any problems with a single coat of primer covering it, but they stuff I've used wasn't quite as dark blue.

  9. Expert Member
    BILL WICHERS | | #10

    When you go to prime that blue drywall, have the paint store tint the primer for you. A few drops of black usually helps with hide, or have them tint the primer to a full-on gray since a neutral color will be less likely to show through your color coat.


  10. lekawa | | #11

    👍🏼 Thank you!

  11. Expert Member
    Dana Dorsett | | #14

    Blue gypsum board facers are usually subtly textured to offer better grip skim-coat hard plaster (with no scratch coat, no lath) than the more generic gypsum board (that is light paper so as to not affect paint color.) The moisture ratings for blue board aren't anything special.

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