Drywall, also called wallboard, plasterboard, or gypsum board, forms the flat surfaces of walls and ceilings in most modern homes. It replaced plaster because it installs faster, repairs more easily, and cracks less. Panels share one clever detail: tapered edges on the long sides form a shallow recess for tape and joint compound, which allows invisible finished joints. Choose the wrong board for a damp basement or an attached garage, though, and you will fight mold or fire code problems for years. Projects that add a partition or close off a room often involve taping new drywall to existing painted drywall, so the seam work has to blend with what is already there.
What Drywall Is Made Of and Why the Edges Matter
Most drywall consists of a gypsum core sandwiched between two sheets of heavy paper. Gypsum is ground, mixed with water and additives, extruded between the paper facings, and dried in continuous sheets. The result is a rigid panel that cuts with a utility knife, scores on one side, and snaps cleanly along the score line.
Plaster still outperforms drywall in some ways: a three-coat plaster wall is harder and more durable, and historic homes often need lime plaster for authentic repairs. Drywall wins on speed, cost, and repairability, which is why it dominates new residential construction. A damaged plaster wall needs a skilled professional, while a damaged drywall panel can be patched in an afternoon.
Gypsum, Paper, and Additives
Additives change how the panel behaves. Fiberglass reinforcement improves fire resistance, wax and water repellents protect against moisture, and special facings resist mold growth. The same core recipe can therefore produce very different boards depending on the coating and the additives mixed in.
Tapered Edges and Invisible Joints
When two panels meet, the tapered edges create a shallow recess. Joint compound fills the recess while paper or mesh tape bridges the seam. After two or three coats, sanding, and primer, the joint disappears. The technique is identical whether you finish new work or taping new drywall to existing painted drywall during a remodel. Cutting a panel takes four steps:
- Score the face paper along a straightedge.
- Snap the board away from the score line.
- Cut the backing paper with the knife.
- Sand or shave the edge to fit tight against the studs.
Seven Types of Drywall at a Glance
Manufacturers color-code most boards so a quick look at the facing identifies the type. A refresher on bathroom drywall types and how they resist moisture makes the rest of the selection straightforward. The seven common options are standard white board, moisture-resistant green board, mold-resistant purple board, fire-rated Type X, soundproof board, VOC-absorbing board, and ECO board made from recycled material.
| Type | Facing color | Key property | Best use |
|---|---|---|---|
| Standard | White | General purpose | Living rooms, bedrooms, ceilings |
| Moisture-resistant | Green | Water-repellent core | Bathrooms, laundry rooms |
| Mold-resistant | Purple | Fungus-inhibiting facings | Basements, crawl spaces |
| Type X | White or pink | Fire-rated core | Garage walls, stairwells, code assemblies |
| Soundproof | Various | Denser core dampens noise | Bedrooms, home theaters, shared walls |
| VOC-absorbing | Blue or white | Adsorbs formaldehyde | New construction, nurseries |
| ECO board | Gray | Recycled material, concrete look | Feature walls, commercial spaces |
Cost separates the types as much as performance. Standard half-inch board runs about $0.40 to $0.60 per square foot at typical retail prices, while green, purple, and Type X boards cost 30 to 60 percent more, and soundproof or VOC-absorbing panels can double the price. Buy the cheapest board that meets the room’s real requirements.
Color Coding and Labels
Green board is not waterproof, a common misconception. It resists moisture better than standard board but still fails when exposed to standing water. Purple board adds mold resistance, and paperless fiberglass facings remove the paper that mold feeds on entirely.
Thickness Options
Panels come in 1/4-inch, 3/8-inch, 1/2-inch, and 5/8-inch thicknesses. Half-inch board handles most residential walls, 5/8-inch is required for fire-rated Type X assemblies, and thin 1/4-inch board curves over arches or patches damaged surfaces. Longer panels, 10 to 16 feet, reduce the number of joints on tall walls and ceilings.
Moisture-Resistant and Mold-Resistant Board for Wet Areas
Bathrooms, laundry rooms, and basements need board that tolerates humidity. Green board works in bathrooms that are ventilated and painted with a waterproof coating, while purple board suits mold-prone basements and crawl spaces. Even moisture-resistant panels need proper detailing: outside corners in wet areas should be finished with corrosion-resistant corner beads, because standard metal trim rusts in humid air.
Green Board in Bathrooms
Install green board around tubs, showers, and vanities, then cover it with tile, waterproofing membrane, or a vapor-retarding paint. Do not rely on the board alone: grout and caulk failures let water reach the core, and no gypsum panel survives prolonged soaking. Green board runs roughly 20 to 30 percent more than standard board, a small premium for a space that stays wet for years.
Purple Board and Paperless Facings
Purple board combines moisture resistance with a mold-inhibiting additive in the core and facings. Paperless fiberglass-faced panels go further and are specified in commercial kitchens and locker rooms. All three options cost more than standard board, so reserve them for spaces that actually see water.
Fire-Rated Type X and Soundproof Panels
Type X drywall contains glass fibers that hold the gypsum core together under heat, giving the assembly a one-hour fire rating when installed per code. Local building codes specify where it is required, typically attached garages, stairwells, and furnace rooms. Soundproof board uses a denser core and sometimes a viscoelastic layer to absorb sound energy.
Type X for Code Compliance
Check the code before you frame: many jurisdictions require 5/8-inch Type X on the wall between a house and an attached garage. Standard board there fails inspection and exposes the home to unnecessary risk. Fire caulk, properly taped joints, and sealed penetrations complete the assembly.
Soundproofing for Bedrooms and Media Rooms
Soundproof panels cut noise transfer between bedrooms or a home theater and the rest of the house. Pair them with insulation in the cavity and resilient channels for the best result. Finishing these panels creates fine gypsum dust, and dust-free drywall sanders keep the cleanup from spreading through the whole house.
VOC-Absorbing and ECO Boards
VOC-absorbing board carries a carbon or mineral layer that pulls formaldehyde and other volatile organic compounds out of indoor air. It suits new construction, nurseries, and offices where off-gassing from paint, cabinets, and furniture is a concern. ECO board is made from recycled gypsum and paper, and some versions are finished to look like concrete for feature walls without the weight of real concrete. The concrete-look finish hides joints less forgivingly than flat white board, so panel layout needs extra care on feature walls.
ECO Board and Recycled Content
Recycled-content panels reduce landfill waste and can contribute to green building certifications. Contractors weigh the different types of drywall and their benefits before specifying panels, because the price premium for specialty boards has to earn its way back in performance.
VOC Adsorption in New Construction
Formaldehyde levels are highest in the first months after construction, when new paint, particleboard, and engineered wood release gases. VOC-absorbing board adsorbs these compounds onto its surface over time, and some manufacturers claim measurable reductions in indoor concentrations when panels are paired with ventilation.
Matching the Board to Your Project
Start with the room, then the code, then the budget. The board that works in a dry bedroom fails in a shower alcove, and the cheapest panel cannot satisfy a fire-rated assembly. Bring room dimensions and a list of openings such as windows and doors when you order, so the supplier can estimate waste accurately.
Questions to Answer Before Ordering
- Does the space get wet? Green or purple board for bathrooms, laundry, and basements.
- Does the code demand a fire rating? Type X for garage and stairwell walls.
- Does noise travel between rooms? Soundproof board for bedrooms and media rooms.
- Is indoor air quality a priority? VOC-absorbing board in nurseries and offices.
- Does the design call for a concrete look? ECO board for feature walls.
Ordering and Storing Panels
Order 10 percent extra for cuts, mistakes, and damaged sheets, and store panels flat on blocks off the concrete floor so they do not absorb moisture. For long finishing runs, a self-mudding drywall tape dispenser speeds up taping considerably and keeps compound off your hands.
The right board only performs when paired with correct installation methods and finishing techniques. Match the panel to the environment, hang it with proper fastener spacing, tape and mud the joints, and prime before painting, and a drywall wall will stay flat and crack-free for decades.