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Guide to Non-Toxic Drywall: Types and Brands

July 11, 2019 by Corinne 22 Comments

This post contains affiliate links, upon purchase, I earn a small commission at no extra cost to you.

“Mudding Sheetrock” by Forest Service – Northern Region is licensed under CC BY 2.0

Drywall is also called gypsum board, sheetrock, plasterboard, or more generally, wallboard. We are going to look over the types and brands, and which chemicals they contain. Which ones have the least toxic additives, don’t offgas and are the healthiest choices.

For assistance with choosing the best wallboard for your needs, sensitivities, and budget, you can contact me for a one-on-one consult. 

What is Drywall Composed of?

The main ingredient in drywall is gypsum, so let’s start there and look at the health considerations of gypsum. There are two types of gypsum:

Natural Versus Synthetic Gypsum

Natural gypsum is a product mined from the earth. Synthetic gypsum is made from the byproduct of power plants, also called FGD gypsum. They are both technically gypsum.

Unless a product specifically states they use natural mined gypsum, it is exceptionally difficult to track which brands use which type, or if they use a mix.

  • 30% of all drywall in North America is synthetic
  • USG, the largest drywall manufacturer, has 21 drywall plants. 9 of those only use synthetic. 6 use a mix of the two Source
natural gypsum mineral

What Else is Drywall Made up of?

  • Drywall is 70-90% gypsum (synthetic, mined or mixed)
  • 10% paper, on the paper-backed types

Other additives may be included:

  • Cellulose fibers (in monolithic drywall)
  • Fiberglass fibers (fiberglass is in X and C types, and fiberglass backed drywall)
  • Plasticizers
  • Starch
  • Finely ground mica crystal as an accelerant
  • EDTA or other chelating agents
  • Boric acid/borates
  • Wax like paraffin or hydrocarbon, or silanes to hinder water absorption (on the greenboard types)
  • Potassium sulfate
  • Sodium sulfate
  • Vermiculite (in Type C fire resistant drywall)
  • EVA as an adhesive

Source 1, source 2, and SDS sheets

Does Synthetic Drywall Contain Mercury?

Both synthetic and natural gypsum contain low amounts of mercury. It is regulated by the UL standard (ULE 100).

How Much Mercury is in Drywall?

The amount of mercury in synthetic gypsum varies depending on the power plant it came from (source).

It is also a trace metal found in natural mined gypsum. One study found the amounts were 0.92 ng/m2-day for natural gypsum wallboard and 5.9 ng/m2-day for synthetic gypsum wallboard. This resulted in mercury levels in the rooms that were below the background levels normally found indoors and within or below the levels found in outdoor air (source).

Therefore, mercury in drywall has not been a major concern of mine in the past. If you wanted to avoid all gypsum board you would be looking at alternatives like MgO board, covered here, tongue and groove wood (not allowed by all codes due to fire risk), or plaster and lath (wood or metal lath).

Or you could minimize the amount of mercury by going with natural gypsum.

Non-Toxic Drywall – Types & Brands

Natural Gypsum

nationalgypsum.com

National Gypsum makes natural gypsum boards that are VOC-free (the paper backed ones).

Their standard line is the regular Goldbond. LITE may also work well for sensitive folks. More on Light drywall below. The type X is a fire-rated drywall, it contains fiberglass.

You can source this through your contractor’s suppliers. You can get a test sheet at Lowes.

I would rather not have recycled paper-backed drywall. But the other major brands also use recycled paper.

Synthetic Gypsum (and Mixed)

USG, Georgia-Pacific and CertainTeed are the three main drywall producers in North America along with National Gypsum above. These are all easy to source at all building supply stores and through contractors.

The gypsum could be natural, synthetic or mixed, and it’s very difficult to find out which drywall line contains which type of gypsum.

USG SheekRock

usg.com

This is the largest drywall brand and the easiest to source. The SDS sheets claim 0-VOC. They also have GreenGuard Gold certification, which I discuss more below.

The “regular” drywall should contain the least amount of additives (in all the brands). They have the recycled paper, but there should be no mildewcide, fiberglass or other major additives.

USG Sheetrock Ultralight – I have been happy with their Sheetrock Ultralight, I did not pick up any offgassing or moldiness in the paper. Although we don’t know what the blowing agent is, I would feel comfortable using this one in my home due to my own testing of it.

This one is inexpensive and easy to find. You can get it at Home Depot or through your contractor.

USG Firecode X – Research that a very sensitive client revealed that USG was the cleanest gypsum on the West Coast (as it contained more natural gypsum). Though these things change over time, and that same brand could be made in a different factory on the East Coast.

It does not contain a flame retardant, it does contain glass fibers (fiberglass). More on type X below.

Georgia-Pacific

buildgp.com

Georgia-Pacific Gypsum boards are all GreenGuard Gold Certified. Their exact VOC levels are not listed on the SDS.

Like the other brands, they have a “standard” which is what I would recommend as the safest bet. The light can be considered as well.

GP DensArmor Plus is the most popular fiberglass backed drywall. No paper here. They recently made a statement that the Dens line can be treated with biocides.

Certainteed

certainteed.com

CertainTeed Gypsum boards claim 0 VOC (no reportable VOCs), and they have GreenGuard Gold certification.

They have all the same categories of drywall types as the others.

Should you use Paper-Backed or Fiberglass backed?

Many drywall companies use recycled paper which some folks are reluctant to use in their homes. One study showed that paper is already full of mold spores (source). The other concern is that if it gets wet it will mold faster than other materials.

If that is a concern of yours, I would check out the fiberglass backed drywall and see if that is tolerable for you. Fiberglass has some offgassing.

If it isn’t, keep in mind that you should not have moisture or condensation behind your wall if your wall is designed and built right. If you have a big leak you are likely to find that quite quickly. I would not rule out paper-backed drywall, personally.

USG Fiberock Monolithic Drywall

Another type of drywall is called monolithic drywall – no paper and no fiberglass – such as the USG Fiberock line.

It does not have a backing, instead, it contains cellulose fibers dispersed throughout the gypsum. This is a more unusual type, but you should try and test this out for you if you have to rule out the other two types.

Paper backed is the least expensive type, followed by fiberglass backed, and then monolithic.

Behind wet areas, concrete backer board should be used (not drywall), that is discussed in the post on bathrooms.

Types of Drywall with Special Properties – Which Chemicals are Added?

Fire-Rated Drywall

USG SheetRock Firecode C

Type X drywall means it meets requirements for fire codes (that could be required in certain rooms of a house). This type contains glass fibers, is denser, and is 5/8th thick (regular drywall is ½ inch).

It is 10-20% more expensive than regular drywall.

Type C is another type of fire-rated drywall, with a higher rating than type X. It also contains fiberglass and a form of vermiculite. It is more expensive than type X and may be specified for certain areas.

Drywall that Reduces Formaldehyde

Certainteed AirRenew

CertainTeed’s AirRenew (GreenGuard Gold), claims to soak up formaldehyde. However, it contains a biocide that is likely not healthy.

It is a little harder to source than the ones above. In Canada, you can find it at Lowes. Some have reported an odor with this one that might indicate that an additive used to soak up formaldehyde might not work for everyone.

This patent might be related to this brand.

Light Drywall 

USG SheetRock Ultralight

The major drywall companies all have lines that are lighter in weight, and these are very commonly used. We don’t know what is in light drywall that makes it light.

From my testing of it, I did not find that it had chemical offgassing, but we don’t know what the blowing agent is (it could be air or something that dissipates quickly) source.

I did well with USG Sheetrock UltraLite, and I don’t suspect a toxic blowing agent.

Borates are likely to be found in light drywall (source). The SDS will sometimes list borax.

Mold Resistant Drywall 

Both the monolithic (homogenous) drywall and fiberglass backed are slightly less prone to going moldy (or at least to going moldy as quickly) compared to paper backed.

Fiberglass backed may be promoted as more mold-resistant, the brands I have looked at including Dens line does contain mildewcide.

Biocides are commonly used in the paper backed lines, if they are labeled as mold resistant.

USG SheetRock Mold Tough line

Paperbacked brands with mildewcide in them include:

  • Georgia-Pacific’s ToughRock Mold Guard (unclear what it is treated with)
  • Certainteed’s M2Tech (unclear what it is treated with)
  • National Gypsum Goldbond XP (treated with thiabendazol, azoxystrobin and fludioxonil)
  • USG Sheetrock Mold Tough line (treated with sodium pyrithione)

Greenboard is a generic term for green colored drywall like these that have treated paper and are meant for areas with more moisture. It is still paper backed.

GP’s ToughRock Mold-Guard, American Gypsum’s Aquabloc and Sheetrock Mold Tough are greenboard.

Purple drywall by National Gypsum is similar to greenboard. They claim it is treated for mold prevention.

Additional Health Concerns with Drywall

Greenboard

Use the Schulter system over backer board

It is not best practice to use greenboard (including purple) behind tiles that get wet. Best practice here is to use concrete backer boards with the Schluter system discussed in this post on bathrooms. If you want to create a mold preventative shower, Schulter is no question the best system.

Using greenboard behind wet tiles can lead to mold if there is moisture.

They also contain added mildewcides, so I prefer to avoid these types of drywall.

Sulphur Emitting Drywall

The “Chinese Drywall” debacle is the best-known case of a major problem in the drywall industry. For a time (2001-2009) some drywall offgassed sulfur to the point of causing major problems. There have also been lawsuits against American made drywall, but they were dismissed source). I have not seen any issues with sulfur and drywall lately.

In every industry, these kinds of problems do crop up from time to time. Those very sensitive should use their own reactions to guide them. Drywall should never smell like sulfur, and if you react to it that won’t be good for you.

Those who are healthy or less sensitive should go with well-respected companies and do the best you can with the research that we have. Made in America may be better, but is no guarantee that there will not be problems.

The problematic drywall also contained strontium.

Silica Dust 

When drywall is cut and when joint compound is in dust form (straight out of the bag or after sanding), silica, the same substance that glass is made of is, is harmful to breathe in. Silica is perfectly safe when in solid form.

Be sure to take great caution when mixing up drywall mud, when cutting drywall and when sanding the mud.

Use an N95 mask or better when around the dust. I use these masks all the time for many purposes.

The dust is very fine and difficult to remove, I have seen it in builds that are 2 years old. It clings to the wall so you have to clean it very thoroughly.

Make sure the central HVAC is off when drywall and drywall mud work is being done, there should never be drywall/silica dust in your ducts.

Products containing silica dust/quartz will have a Prop 65 warning, keep in mind it’s safe when in solid form.

Should your Drywall be Certified – GreenGuard Gold or UL?

The only benefit to a Greenguard Gold product is it might catch these unusual problems with offgassing that have cropped up – either sulfur or formaldehyde.

More than a decade ago, some drywall did test positive for formaldehyde, in that sense, GreenGuard Gold is the best certification for this case, as it ensures the levels are extremely low, the same as outdoor air. More details on GreenGuard levels in this post on certifications.

Those who do not want to over-research should go with a big brand Greenguard Gold line that does not contain mildewcides. National Gypsum Goldbond if you want natural mined gypsum.

Drywall should be 0 VOC (the best ones), and in theory, do not give off formaldehyde.

UL 100 is somewhat helpful in that it regulates mercury, but I expect all drywall to have very extremely minuscule levels of mercury.

For drywall mud (spackle/joint compound), drywall tape, and mud for textured walls see my dedicated post on this topic.

For assistance with choosing the best wallboard for your needs, sensitivities, and budget, you can contact me for a one-on-one consult. 

Did you find this post helpful? If so you can buy me a coffee to support the research behind this blog. Thank you!

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Sources:

1) https://www.buildinggreen.com/primer/synthetic-gypsum
2) https://www.thespruce.com/what-is-drywall-made-of-1821482
3) SDS sheets for all the major brands
4)http://www.teledyneleemanlabs.com/resource/Application%20Notes/AN1301%20Determination%20of%20Mercury%20in%20Synthetic%20Gypsum.pdf
5) www.ncbi.nlm.nih.gov/pubmed/19452875
6) https://www.researchgate.net/publication/298054499_Pre-contamination_of_new_gypsum_wallboard_with_potentially_harmful_fungal_species
7) http://www.freepatentsonline.com/y2011/0113961.html
8) https://www.thespruce.com/ultra-light-drywall-1821478
9) https://www.borax.com/BoraxCorp/media/Borax-Main/Resources/Brochures/borates-gypsum-board.pdf?ext=.pdf
10) https://www.propublica.org/article/american-made-drywall-emerges-as-potential-danger

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Filed Under: Healthy Building Tagged With: Healthy building

Reader Interactions

Comments

  1. Sarah says

    January 13, 2021 at 10:32 am

    Thank you for this very helpful post. I am doing a reno at my house in Texas and thought I would share that I reached out to USG about their drywall. They told me that the drywall coming from their Sweetwater, TX plant is all natural. So if you are able to source from that plant, you should be getting natural gypsum. Hopefully this is helpful to others.

    Reply
    • Corinne says

      January 13, 2021 at 10:38 am

      Thank you!

      Reply
  2. Ana says

    January 9, 2021 at 8:57 pm

    What type of drywall would you recommend for a basement? It seems that you don’t recommend green boards?

    Reply
    • Corinne says

      January 11, 2021 at 12:15 pm

      Ideally the basement walls are unfinished (painted or plastered concrete). I personally would not finish them out. But if you do it should be designed in a way that regular drywall will work just fine. For high humidity I have a slight preference for fiberglass backed over green board as green board still has the paper but it is soaked in more chemicals. I don’t think that is the solution in any situation for high humidity. There are also construction methods to keep the drywall off of the floor in case of flooding.

      Reply
  3. Jessica A Pearlman says

    December 18, 2020 at 1:42 pm

    Hi Corine, I just spoke with National Gypsum. It sounds like they do still use synthetic gypsum although they are phasing it out.

    —Jessics

    Reply
  4. Joan says

    December 10, 2020 at 11:53 am

    My contractor is using USG compound that is dustless. I have been having burning sinuses, sore throat, bad headache now for almost a week. What could it be that’s causing this?

    Reply
    • Corinne says

      December 11, 2020 at 9:53 am

      The premixed compound definitely offgasses.

      Reply
  5. Paula says

    November 12, 2020 at 8:11 pm

    I’m unclear about your stance on mildewcides and your section on “Mold Resistant Drywall”… are you recommending those? Or not, because they contain mildewcides? Mold is bad, but aren’t mildewcides also “bad”? If so, what type of drywall should be used in areas like an untiled bathroom?

    Reply
    • Corinne says

      November 13, 2020 at 1:04 pm

      They are not great, but they’re also not the worst chemical out there. I would prefer to use concrete backer board in almost all situations.

      Reply
      • Paula says

        November 13, 2020 at 2:24 pm

        It’s my understanding concrete backer board is for use behind tiles…but I’m using acrylic surrounds for my showers and I’m not tiling my remaining bathroom walls. Concrete backer board can’t be used in place of drywall for entire bathroom walls (that aren’t behind showers), can it?

        Reply
  6. Ali says

    August 3, 2020 at 5:58 pm

    Hi there, so over all-would you day USG is safe to use? And I can not find where it states that they have green guard gold cert? Any ideas where they may have that listed? Are all types of USG safe or only specific lines? Thanks so much!

    Reply
    • Corinne says

      August 3, 2020 at 7:17 pm

      The drywalls I checked out by USG are well below Greenguard gold. There are some slight variations of the gypsum between factories but the other ingredients will be the same across that brand. https://usg.gcs-web.com/news-releases/news-release-details/usg-earns-greenguard-gold-certification

      Reply
  7. elije burge says

    March 15, 2020 at 8:41 am

    hempcrete with lime wash and clay based skim, non toxic , environmentally friendly big time, and self healing

    Reply
  8. Michael says

    March 10, 2020 at 8:46 pm

    So Lowes carries the only natural gypsum which I guess is the best stuff to go with for MCS? The link you provided says it’s a fireshield panel? So this has fiberglass? I’m so confused.

    Reply
    • Corinne says

      March 11, 2020 at 7:20 pm

      National Gypsum has lines that are regular, lite and fire rated. The fire rated types do have fiberglass.

      Reply
      • Michael says

        March 12, 2020 at 6:52 pm

        Thank you for your reply. So would the lowes brand, National gypsum(or goldbond?) be natural gypsum and therefore the best choice as far as drywall for MCS people?

        Reply
  9. Stacey says

    February 25, 2020 at 12:20 pm

    Has anyone tested USG Fiberock Monolithic Drywall for detectable off-gassing? Curious to hear people’s feedback. If not, other than potentially price, it seems like there’s no downside?

    Reply
  10. Anna says

    November 10, 2019 at 5:27 am

    People buy these mold resistant drywall units and then use regular joint compound or paper tape. That never made sense to me. Why spend extra on your special mold resistant drywall if the joint compound and paper tape is predisposed to mold…

    Schluter system is the most logical thing you can do. I was about to purchase MgO or DensArmor Plus boards for a higher humidity room and in areas directly behind sinks, and then I was baffled by zero selection of mold resistant joint compounds. It logically made no sense to me to invest in this mold resistant drywall only to get mold prone joint compound. And if I did decide to go with a mold resistant joint compound with a fiberglass tape (to truly make it a mold resistant system), then I would have a biocidal chemical product, which would defeat the purpose of my non toxic theme home. That's when I started to read up on the Schluter system for showers and tubs and Caliwell paint in higher humidity rooms of the house.

    Reply
  11. Corinne says

    September 17, 2019 at 6:42 am

    There is no special drywall mud for bathrooms. Your humidity should not stay over 60% for long periods of time though.

    Reply
  12. Anna says

    September 13, 2019 at 11:08 pm

    What type of drywall mud is compatible in high humidity areas?

    Reply
  13. Anaphylaxing says

    January 25, 2015 at 5:13 am

    Love this post. Aerated Autoclaved Concrete appeals the most to me. They can ship it to Canada but the trucking fee was significant.

    Reply
    • Corinne says

      January 25, 2015 at 5:14 am

      that's good to know!

      Reply

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Hi, I’m Corinne, I am a Certified Building Biologist Practitioner with 6 years of experience helping people create healthy homes.

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