Question

I am having my breakfast room remodeled. I know that premixed joint compound is toxic, but is dry mix mixed onsite OK?

Asked by Carole
Columbus, OH

Should I use a special drywall or tape?

Answer

Mary Cordaro

Answered by Mary Cordaro

Southern California Areas, CA

Mary Cordaro, Inc.

October 7, 2010

Dry mixes in general are a better option than ready-mix joint compounds.

In fact, a colleague at American Clay, in his search for less toxic fast-set products for manufactured housing, including for the chemically sensitive, recently spoke with a credible formulary technical expert at USG (US Gypsum) about this very topic. He was told that USG dry-mix products are biocide-free, and are generally made with minerals, with some starch and cellulose.

  • This is good news, as biocides, such as triclosan, are often not required to be listed on MSDSs, but can be very toxic, even in small amounts, and are common ingredients in many lifestyle, household, and building products.
  • There are many types of biocides in building products, and if possible, it’s best to avoid or at least minimize their use in a healthy home, particularly if you are chemically sensitive.

Although the description from the USG expert is a general one only, it does indicate that some mass-marketed, conventional dry mixes contain fewer toxic chemicals than ready-mix versions. You can find USG dry-mix products here.

Look carefully for toxic ingredients in dry mix joint compounds

However, here’s why it’s not possible to state that all dry-mix products are safe: if you take a close look at the MSDSs for dry-mix joint compounds on USG’s website, those products may still contain ingredients that are not contained in the list of least toxic products in my earlier joint compound Q&A here.

To give you an idea of how dry mixes can vary, here’s an ingredient comparison of three USG dry-mix joint compound products, with the assumption that the USG formulary tech’s generalized description is correct:

  1. Beadex Silver Set Lightweight Setting-Type Joint Compounds: The MSDS for these products reports no formaldehyde, aldehyde, vinyl alcohol polymer, or vinyl acetate monomer. So if this product is right for your particular application, this product looks to be nontoxic.
  2. Sheetrock brand AP Lite Lightweight All-Purpose Joint Compound: The MSDS for this product reports no formaldehyde, aldehyde or vinyl acetate monomer, but it does contain vinyl alcohol polymer. The amount is small by percentage, but if you are looking for a chemical-free product, this product may not be right for you.
  3. Sheetrock brand Durabond Setting-Type Joint Compounds: The MSDS for this product reports that it contains vinyl acetate monomer, acetaldehyde and formaldehyde. All of these ingredients are best avoided, particularly if you are chemically sensitive or have other health concerns.

So if your budget and timeline do not allow for the healthiest options available, and you are not chemically sensitive or suffering from other serious health conditions,

  • look carefully at conventional dry mixes, to make sure they are as chemical-free as possible, and
  • ensure the product you choose is the right one for the specific application.

By the way, a product that is LEED-certified and green labeled/tested is not necessarily chemical-free. Use the same critical analysis on green-labeled products as those that are not.

Still the safest joint compounds

If you want to be sure that the products you use are the healthiest possible, and if you don’t feel able to ascertain on your own if a conventional dry mix is both nontoxic and the right product for your job, then you can always rely on the following products.

If they fit into your budget and timeline, and/or you are pregnant, planning a family, or if anyone in your household has serious health concerns, I highly recommend them.

  • KEIM Dolomitspachtel, the only ready-to-use, premixed, chemical-free, biocide-free joint compound. The natural lime in this joint compound preserves the product without chemical biocides. This product is more expensive than conventional ready-mix joint compounds.
  • Murco M-100, a dry, chemical-free joint compound. Murco is a very popular alternative, successfully used by many contractors, but requires more labor time. Some contractors don’t feel that it provides a hard enough surface, however, or feel that it may crack more easily in earthquake-prone areas.
  • Hamilton Smooth Set and Smooth Set Light Weight, also called Westpac Fast Set and Fast Set Lite . To avoid biocides, purchase Hamilton Smooth Set or Smooth Set Light Weight, Westpac Fast Set and Fast Set Lite in bags only (not boxes), and do not purchase Eco-Finish or any other versions offered by Hamilton and Westpac.
  • Smooth Set and Fast Set are actually patching compounds, but as long as a contractor is skilled with applying fast-drying plasters, this is a great, healthy alternative product that dries very hard. However, it does require more labor and definitely more application skills.


For more information:

Read Mary Cordaro's Q&A "Is joint compound really safe? I'm concerned about polyvinyl acetate binders."

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