Regular Drywall (Standard White Board)
Regular drywall is the standard gypsum board with a gray or off-white paper facing. It's what most interior walls and ceilings are made of.
This type works for any room without moisture or fire concerns. Bedrooms, living rooms, hallways, closets. Pretty much anywhere that stays dry and doesn't need special fire protection.
At my local Home Depot, a 4x8 sheet of 1/2-inch regular drywall runs about $13 to $15. Prices have bounced around a lot in the last few years. I remember paying $8 a sheet back in 2018. Those days are gone.
When to Use Regular Drywall
Use it for standard interior walls and ceilings in living areas. If the room isn't a bathroom, laundry room, kitchen, or garage attached to the house, regular drywall is probably fine.
Moisture-Resistant Drywall (Green Board)
Moisture-resistant drywall is a type of drywall with a water-resistant paper facing and gypsum core. The green color makes it easy to identify at the store.
Green board handles humidity better than standard drywall. It's designed for areas with occasional moisture exposure, like bathrooms (away from direct water contact), laundry rooms, and basements. The key word is "resistant," not waterproof. It can still fail if it gets consistently wet.
Price wise, green board costs about $18 to $22 for a 4x8 sheet around here. That's maybe $5 to $7 more than regular. My bathroom mistake cost me $2,300 to fix because I saved $40 on the initial material. Do the math.
When to Use Green Board
Use it in bathrooms (walls, not directly around showers), laundry rooms, and basements. Some codes require it in kitchens too. Check your local requirements before starting.
Don't use green board inside shower enclosures or anywhere that gets direct water. That's cement board territory.
Mold-Resistant Drywall (Purple Board)
Mold-resistant drywall is a type of drywall with a fiberglass mat facing instead of paper, treated to resist mold and mildew growth. The purple color is a branding thing, but it's become the industry shorthand.
Purple board takes moisture resistance further by eliminating the paper that mold likes to eat. It's more expensive but also more protective in high-humidity environments.
Expect to pay $28 to $35 per 4x8 sheet. Neighbor Dave used it when he redid his basement after a flood. "Not making that mistake twice," he said. His previous basement had standard drywall and grew enough mold to be a health hazard. The remediation cost him over $6,000.
When to Use Purple Board
Use it in basements, bathrooms, anywhere with known moisture problems, or if your area has high humidity year-round. Also good for homes with a history of water intrusion.
Overkill for dry bedrooms and living areas. Reasonable insurance for anything below grade or near plumbing.
Fire-Rated Drywall (Type X)
Type X drywall is a type of drywall with glass fibers embedded in the gypsum core that allows it to resist fire longer than standard drywall. A 5/8-inch Type X sheet provides about one hour of fire resistance.
Building codes often require Type X in specific locations. Garage walls and ceilings that adjoin living spaces are the most common example. It's also required in many commercial applications and multi-family housing.
Type X runs about $16 to $20 per sheet in 5/8-inch thickness. Not much more than regular drywall, and you might be legally required to use it anyway. Uncle Frank always says to check the code before buying anything.
When to Use Type X
Use it where code requires: attached garages, utility rooms with furnaces or water heaters, between units in multi-family buildings, and anywhere the inspector tells you to.
Even if not required, Type X makes sense in garages and around heating equipment. A few extra dollars per sheet for some fire resistance isn't a bad investment.
Quick Comparison
Here's what I'd buy today if I was starting a project:
For a bedroom or living room: regular drywall, $13 to $15 per sheet. For a bathroom (walls only): green board, $18 to $22 per sheet. For a basement: purple board if budget allows ($28 to $35), or at minimum green board. For an attached garage: Type X fire-rated, $16 to $20 per sheet (likely code-required anyway).
Pete at the hardware store once told me that mixing types in one project is fine. Use green board in the bathroom, regular in the adjacent hallway, Type X in the garage, whatever the room needs. You don't have to pick just one.
The Takeaway
Spend the extra money on specialty drywall where it matters. The price difference is small compared to fixing mold damage or failing an inspection. I learned that lesson the expensive way in my bathroom, and I've never bought the wrong type since.