## Pre-installation Preparation

1. **Inspect framing and layout** – Before drywall arrives, ensure studs and ceiling joists are plumb, true and securely fastened. National Gypsum’s installation guide recommends verifying the on-center spacing of the framing and marking receptacles or other penetrations before cutting boards【641681652487939†L234-L240】.

2. **Cut to length and mark openings** – Measure the wall or ceiling and cut boards to length using a drywall saw or utility knife. Mark out electrical boxes and other openings so that cuts can be made prior to hanging【641681652487939†L243-L256】.

## Hanging Drywall

1. **Orientation matters** – Standard residential construction uses 4-ft-wide panels. For ceilings, boards are often hung perpendicular to the joists because the board edges are supported by the framing at each joint. For walls, boards may be hung horizontally (perpendicular to studs) or vertically. National Gypsum advises hanging boards at right angles to the framing, starting at the top and working down【641681652487939†L243-L256】.

2. **Fastening** – Use bugle-head drywall screws rather than nails for improved holding power. Screws should be 1¼ inches long for ½-inch drywall (longer for thicker board) so they penetrate at least ½ inch into wood framing. The Spruce notes that for a standard sheet, 1¼-inch screws are typical【54236383197167†L416-L419】. When driving screws, set the head just below the surface without tearing the paper. Fine Homebuilding stresses that the screw should leave a slight dimple; if driven too deep it will tear the face paper and reduce holding power【331675774179357†L69-L81】.

3. **Fastener spacing** – Local building departments follow the International Residential Code (IRC). Placer County’s drywall inspection checklist (used throughout California) summarizes IRC Table R702.3.5: for ½-inch board on walls, screws are spaced 16 inches on center with framing at 16 inches and 12 inches with framing at 24 inches【100967013599658†L34-L41】. Ceilings require 12-inch screw spacing【100967013599658†L34-L41】. For 5/8-inch board, the spacing is typically 7 inches on ceilings and 12 inches on walls【311291640836506†L214-L267】.

### Using Adhesive

Screws can be supplemented with construction adhesive to strengthen the bond and reduce the number of fasteners. Fine Homebuilding notes that a 3/8-inch bead of adhesive on each framing member reduces fastener requirements by up to 75 percent and creates a stronger bond【331675774179357†L207-L227】. Adhesive is applied along studs and joists, with perimeter screws installed immediately to hold the panel in place【331675774179357†L217-L225】. Panels hung horizontally on walls may require fasteners only at butted seams and along the edges when adhesive is used【331675774179357†L217-L225】. However, adhesive must not be applied over polyethylene vapor barriers or kraft-paper insulation, and panels should be “pre-bowed” (stacked face up overnight) so they press against the glue as it cures【331675774179357†L230-L237】. Allow at least 48 hours for the adhesive to dry before taping and finishing【331675774179357†L236-L237】.

## Why 5/8-inch Type-X Drywall Is Required in Many Southern California Applications

The 5/8-inch Type-X gypsum board, often called **fire-code drywall**, contains special additives to enhance fire resistance. Unlike standard ½-inch board, Type-X is rated to resist fire for at least one hour when installed correctly, making it suitable for separating garages from living spaces. Several code references illustrate the requirement:

- **International Residential Code (IRC) Section R302.6 – Dwelling/Garage Separation** – A private garage beneath habitable rooms must be separated by **not less than 5/8-inch Type X gypsum board or equivalent**【903662164484461†L14-L17】. This requirement was introduced in the 2006 IRC and remains in later editions, including California’s adoption. The IRC does not require the ceiling assembly to be formally fire-rated; a single layer of Type-X board satisfies the separation requirement【903662164484461†L14-L23】.

- **Local building department guidance** – MyBuildingPermit.com’s Tip Sheet 6 (used in many California jurisdictions) reiterates that garages beneath habitable rooms require **5/8-inch Type X board** on the ceiling. Fasteners must be 6 inches on center with 6d cooler nails or 1¼-inch Type-W screws on framing spaced up to 24 inches【652070553923825†L13-L47】. Placer County’s inspection checklist also notes that Type X board on garage ceilings must be fastened at 6 inches on center【311291640836506†L214-L267】.

- **InterNACHI inspection guidance** – The InterNACHI home inspector training notes that garage ceilings with living space above require **5/8-inch Type X gypsum board (fire code)**【922260885897320†L172-L175】. The article contrasts this with ½-inch gypsum board for ceilings with attic space above and underscores the need to weatherstrip pull-down stair openings【922260885897320†L172-L177】.

These requirements ensure that a fire originating in the garage has sufficient resistance to delay spreading into the living space, giving occupants time to escape and firefighters time to respond. Southern California jurisdictions enforce the IRC separation because garages typically store flammable liquids (gasoline, paint thinner) and have gas-powered vehicles or equipment.

## Installation Tips Specific to 5/8-inch Type-X Drywall

1. **Plan for weight** – 5/8-inch panels are heavier (~70–75 lbs per 4×8 sheet) than ½-inch panels, so use a drywall lift or extra help. Ensure framing is adequate; the maximum framing spacing for 5/8-inch board on ceilings is 24 inches on center【311291640836506†L214-L267】.

2. **Fastener pattern** – For 5/8-inch Type-X board on garage ceilings, nails or screws must be spaced 6 inches on center to meet code【652070553923825†L13-L47】. On walls, 12-inch spacing is typical【311291640836506†L214-L267】.

3. **Avoid over-driving screws** – Because the gypsum core is thicker, screws must be driven just enough to dimple the paper without breaking it. Over-driving will weaken the board and reduce fire resistance.

## Summary

When installing drywall in Southern California, follow the IRC and local building department guidance. Use 5/8-inch Type-X gypsum board on garage ceilings beneath living spaces to comply with separation requirements and protect your home from garage fires【903662164484461†L14-L23】. Hang boards perpendicular to framing, use the correct screw spacing, and supplement with adhesive when appropriate. Proper preparation and adherence to local codes ensure a safe, durable and code-compliant drywall installation.