Select Perfect Drywall to Conquer Bathroom Mold and Mildew
Bathrooms can be a breeding ground for mold and mildew due to the warm, humid conditions. Using the wrong drywall allows moisture damage to occur, enabling ugly black mold infestations. Selecting optimal drywall is crucial to safeguard your bathroom walls.
Drywall Vulnerabilities in Bathrooms
Traditional drywall is prone to moisture absorption and mold growth because of its paper facing and gypsum core. Bathrooms often have poor ventilation, allowing persistent humidity. Over time, this dampness seeps into porous drywall.
As moisture accumulates in drywall, mold spores germinate, forming extensive root networks that discolor and degrade surfaces. Mold colonies tend to first establish in ceiling corners then spread to wall crevices and tile grout.
Inhaling airborne mold spores triggers allergic reactions, asthma attacks, and respiratory issues for many people. Long-term exposure may cause chronic sinus congestion, skin irritation, and headaches.
Greenboard Drywall
Greenboard drywall contains moisture-resistant additives that curtail mold and mildew. Its green paper facing has an asphalt additive for enhanced water resistance compared to regular drywall.
Greenboard is suitable for bathroom walls and non-wet areas. While not waterproof, it resists humidity absorption better than basic drywall. Its mold inhibitors also limit fungal growth.
However, greenboard has some shortcomings. It remains vulnerable to significant or prolonged moisture exposure. Fiberglass mesh reinforcement makes it prone to delamination under flooding.
Advantages of Greenboard
- Affordable option for basic moisture resistance
- Specialized paper facing resists dampness
- Mold growth inhibited
Disadvantages of Greenboard
- Vulnerable to extensive water contact
- Not as durable as cement backerboard
- Prone to delamination when flooded
Purple Drywall
Purple drywall enhances moisture protection with added biocides that deter mold and mildew. Its purple facing has fiberglass mesh, moisture resistance, and antimicrobials making it extra durable.
Purple board stands up to high humidity and periodic water contact better than greenboard. Special resins prevent moisture wicking while biocides stop mold colonies from gaining footholds.
However, cement backerboard still surpasses purple board for direct water exposure. Under heavy flooding or pooling water, purple drywall loses its integrity.
Purple Board vs Greenboard
| Purple Board | Greenboard | |
|---|---|---|
| Mold Resistance | Superior antifungal properties | Moderate |
| Water Resistance | Withstands more moisture | Basic humidity resistance |
| Cost | Moderately expensive | Budget option |
Cement Backerboard
Cement backerboard consists of a cement and fiberglass mesh center sandwiched between a cement coating. This exceptional waterproofing makes it ideal for direct water contact areas.
In showers, cement backerboard endures routine soaking without swelling or decomposing. The miniscule pores throughout the cement are too small for water to infiltrate but allow vapor diffusion.
Although rugged against moisture, cement backerboard has some disadvantages. Installation requires specialized tools and materials. The rigid boards are also heavy, difficult to cut, and more expensive than drywall.
Cement Backerboard Drawbacks
- Rigid and heavy boards
- Difficult to cut without special saws
- Higher cost than drywall
- Special installation tools needed
Waterproof Coatings
Applying waterproof paints or coatings enhances moisture protection, especially for vulnerable drywall areas. Many modern options contain antimicrobials to also resist mold.
Membranes are thin, flexible barriers rolled or brushed onto surfaces. Liquid membranes deeply penetrate materials while flexible sheets mount on top. Both barrier types seal pores and microscopic cracks.
Epoxy and enamel paints contain tough resinous solids that water cannot permeate once cured. Some contain EPA registered fungicides that kill existing mold while preventing regrowth.
Coatings are useful for supplementing moisture resistant drywall. However, they may not withstand direct or prolonged wetness without an underlying cement board layer.
Proper Installation and Sealing
Specialized installation procedures for bathroom drywall optimize moisture resistance and durability.
Installation Tips
- Staggered seams prevent moisture wicking
- Seal corners with caulk before taping
- Apply mesh tape for crack resistance
- Waterproof drywall screws prevent rust stains
Applying quality vinyl or silicone sealant to all joints, corners, edges, and penetrations seals pathways for moisture ingress and air leakage. Using specialized corner beads and joint tape designed for bathrooms boosts bonds.
Hiring a drywall professional ensures correct installation. They have the expertise to identify and resolve problem areas.
Adequate Ventilation
Proper ventilation controls bathroom humidity before it damages surfaces and enables mold infestations.
Building codes mandate operable windows or exhaust fans in all bathrooms. Experts recommend 50 cubic feet per minute (CFM) capacity fans that completely exchange air 12 times per hour.
Strategic fan placement over showers or soaking tubs removes moisture laden air most effectively. Units mounted high on walls or ceilings optimize steam and vapor extraction.
Preventing bathroom mold and mildew requires moisture resistant drywall and stellar installation. For showers and tub surrounds, cement backerboard is ideal to withstand routine soaking.
Elsewhere, enhanced products like greenboard or purple drywall better resist humidity alongside waterproof paints and membranes. Ensure every seam is thoroughly sealed while maintaining adequate airflow.