Drywall, also known as gypsum board, wallboard, or plasterboard, has revolutionized interior construction in North America. Its quick installation, ease of use, and cost-effectiveness have made it a preferred alternative to traditional lath and plaster for creating smooth wall and ceiling surfaces. But what exactly is drywall made of, and what should you know about its properties and potential issues?
Drywall Composition: The Inside Story
The core component of drywall is gypsum, a naturally occurring mineral composed of calcium sulfate dihydrate. This gypsum core provides fire resistance, a key safety feature. In its natural state, gypsum isn’t directly usable. It undergoes a process of crushing, heating, and rehydration to create a workable material. Additives are mixed with the gypsum to enhance its properties. Common additives include:
- Mica: Improves flexibility and reduces cracking.
- Clay: Enhances workability and consistency.
- Resin: Increases water resistance.
The prepared gypsum mixture is then sandwiched between two layers of paper. This paper facing provides a smooth surface for painting or wallpapering and also adds strength to the board.
Understanding Drywall Dust and Safety
Working with drywall generates dust composed of gypsum and silica. This dust can irritate the lungs, eyes, and skin. Always wear appropriate personal protective equipment (PPE) when cutting, sanding, or installing drywall. Essential PPE includes:
- Safety glasses: Protect your eyes from dust and debris.
- Gloves: Prevent skin irritation.
- Dust mask or respirator: Safeguard your lungs from inhaling dust particles.
Furthermore, drywall is susceptible to water damage. When exposed to moisture, it loses its structural integrity and becomes a breeding ground for mold. Promptly address any leaks or water intrusion to prevent costly repairs.
The “Problem Drywall” Crisis: A Lesson Learned
In the aftermath of the devastating hurricane seasons of 2004 and 2005, a surge in demand for building materials led to drywall imports from China. Unfortunately, some of this imported drywall was contaminated with toxic chemicals, leading to widespread problems in newly constructed homes.
Homeowners, primarily in Florida and Louisiana, reported a range of health issues, including:
- Upper respiratory irritation
- Headaches
- Irritated and itchy eyes/skin
- Difficulty breathing
- Persistent cough
- Runny nose and sinus congestion
- Sore throats
- Frequent nosebleeds
- Asthma attacks
Additionally, residents noticed a distinct sulfur smell and premature corrosion of metal components, such as air conditioner coils and electrical wiring. The culprit was identified as microbial conversion of excess sulfur in the drywall, resulting in the release of sulfuric acid and hydrogen sulfide.
Identifying Problem Drywall: Key Indicators
The US Consumer Product Safety Commission (CPSC) has established criteria to identify “problem drywall.”
Step 1: Conduct a visual inspection for blackened copper electrical wire or air conditioning evaporator coils in homes with drywall installed between 2001 and 2009.
Step 2: If drywall was installed between 2005 and 2009, look for at least two of the following: for installations between 2001 and 2004, at least 4 conditions must be met:
- Elemental sulfur in the drywall core*
- Black copper sulfide on labels, grounding wires, or air conditioning coils*
- Chinese markings on drywall
- Elevated sulfide gas emissions from drywall*
- Corrosion induced by drywall in test chambers*
*Lab testing is required for confirmation.
The CPSC concluded a strong correlation between Chinese drywall and corrosion issues in US homes. The Drywall Safety Act of 2012 mandated proper labeling (including origin) and sulfur content standards for drywall.
Alt text: Blackened copper pipe, a sign of potential “problem drywall” in homes.
Alt text: Corroded and blackened copper coils in an air conditioner, indicating possible “problem drywall”.
Mold Growth on Drywall: Prevention and Remediation
Standard drywall is vulnerable to mold growth when exposed to moisture. Mold digests the paper covering, leading to dark stains and potential structural damage. Mold can spread to supporting studs, especially if the drywall is concealed behind tiles or other finishes.
Choosing Mold-Resistant Drywall: Green Board vs. Mild-Resistant Options
For areas prone to moisture, such as bathrooms and basements, consider using mold-resistant drywall. Two primary types are available:
- Green board: Offers moisture resistance due to a wax-infused paper facing. The back side is typically untreated. While more resistant than regular drywall, it can still fail if exposed to prolonged or excessive moisture.
- Mild-resistant drywall: Features a fiberglass coating instead of paper, providing superior mold prevention. It’s generally more expensive than green board.
It’s important to note that no drywall is completely waterproof. Proper ventilation and moisture control are crucial in preventing mold growth, regardless of the type of drywall used.
Drywall Ingestion or Eye Contact: First Aid Measures
If drywall is swallowed, do NOT induce vomiting. Immediately consult the webPOISONCONTROL online tool or call Poison Control at 1-800-222-1222 for guidance.
In case of drywall dust entering the eyes, flush them immediately with copious amounts of room temperature water. Remove contact lenses if present. For children, gently pour water onto the bridge of the nose, allowing it to flow into the eyes. Encourage blinking. Seek further assistance from webPOISONCONTROL or Poison Control if irritation persists.
Prevention is Key: Safety Tips for Working with Drywall
- Always wear safety glasses, gloves, and a dust mask during drywall installation and sanding.
- Opt for domestically manufactured drywall that adheres to US safety standards.
- Consider using mold-resistant drywall in moisture-prone areas.
- Ensure proper ventilation to minimize moisture buildup.
Real-Life Scenarios: Poison Control Cases Involving Drywall
Case 1: A 10-month-old girl playing near drywall installation had dust on her hands. Her mother contacted Poison Control and followed instructions to bathe the child and provide food and drink. The child vomited a small piece of drywall but recovered fully.
Case 2: A 3-year-old boy dislodged a towel rack, exposing drywall dust to his eyes and possibly his mouth. His mother called Poison Control, flushed his eyes, and gave him a drink. The boy experienced no further symptoms.
These cases highlight the importance of proactive safety measures and prompt action when drywall exposure occurs.
Additional Resources:
- Chinese-made drywall causing home and health hazards. Consumer Reports. March 19, 2009. Accessed September 29, 2024.
- How can I tell if my home has problem drywall? US Consumer Products Safety Commission. 2009. Accessed September 29, 2024.
- Remediation guidance for homes with corrosion from problem drywall as of March 15, 2013. Accessed September 29, 2024.
References:
- Allen JG, MacIntosh DL, Saltzman LE, et al. Elevated corrosion rates and hydrogen sulfide in homes with ‘Chinese Drywall.’ Sci Total Environ. 2012;426:113-119
- Public health implications of Chinese-manufactured drywall. US Agency for Toxic Substances and Disease Registry. May 2, 2014. Accessed February 25, 2025.
- Hooper DG, Shane J, Straus DC, et al. Isolation of sulfur reducing and oxidizing bacteria found in contaminated drywall. Int J Mol Sci. 2010;11(2):647-655.
- Methner MM. Identification of potential hazards associated with new residential construction. Appl Occup Environ Hyg. 2000;15(2):189-192.
- Tomei Torres FA. Case study: microbial ecology and forensics of Chinese drywall-elemental sulfur disproportionation as primary generator of hydrogen sulfide. Microb Ecol. 2018;76(1):37-48.
