The short answer is that you should multiply the height and width of all wall areas, add up the totals and add another 5% to 10% to cover trim and waste. Consider a detached 22'x30' 2.5-car garage with 10-foot ceilings: 2 walls 22'x10' = 220 + 220 or 440 total square foot. 1 wall 30'x10' = 300 square foot.
If you're tackling a single-car garage, you can expect the total cost to land somewhere between $360 and $840. For a two-car garage, the cost rises to $660 to $1,540. And if you have a larger three-car garage, you could be looking at $930 to $2,170 to drywall the entire space. Keep in mind that these are just averages.
A good rule of thumb is to use one gallon of joint compound for every 500 square feet of drywall.
The drywall estimating rule of thumb suggests that you estimate one drywall sheet (4 ft x 8 ft) for every 32-48 square feet of wall surface. When estimating paint, estimate around one gallon for every 350-400 square feet of wall area.
Rule of Thumb: Estimate approximately 1 sheet of drywall (4 ft x 8 ft) for every 32 to 48 square feet of wall surface. For paint, estimate 1 gallon for every 350 to 400 square feet of wall area.
Understanding Drywall Coverage
A rough calculation would be 3000 sq ft (floor area) multiplied by 2.5 (to account for both walls and ceiling), giving you approximately 7500 sq ft of wall space. Dividing this by the coverage of one drywall sheet (32 sq ft) means you'll need around 234 sheets of drywall.
Always leave a 1/2-inch gap at the floor.
5/8″ is required in some applications. All commercial requires it and residential garages typically have 5/8″ drywall. It is better than 1/2″. Warning, do not use on walls in a residential application as the door jambs will not fit, unless you have specifically purchased larger frame door jambs.
Step 3: Follow with a vapor barrier
In the garage, like other spaces in the home, condensation results from moisture in the air. Excess condensation and humidity levels in your garage can damage your garage's foundation and cause tools, vehicles, and cabinets to rust faster.
In general I use 1 box per 10 sheets. Depending on how many angles, texture, etc.
There are several simple ways to texture a wall. One option is to roll texture on using a pre-mixed texture compound. Another method is to add texture to paint. Alternatively, faux techniques, such as rolling paint on or off with rags or applying a pattern with a sponge, can also create a textured wall appearance.
Calculate how many drywall sheets you will need by dividing the total square footage of area by 32 (if you're using 4-by-8 sheets) or by 48 (if you're using 4-by-12 sheets). If you want to get the cost, just multiply the total number of sheets by the price per sheet. Remember to add local taxes and delivery charges.
That's approximately 35 sheets of 4x8, which you'll probably want to use if you're relative newbie hanging solo. At 100 a sheet that's 3500.
You'll likely need a permit since this project may require soil grading to avoid drainage issues. Repairing your floor may be more cost-efficient than replacing it if grading is necessary. No permit may be required to hang drywall on exposed wooden wall studs in your garage.
You can save a lot of money by installing drywall yourself—usually around an average of $1,400 per project, or between $40 and $70 per panel, depending on the level of finish you want.
Consider 1/2-inch drywall to be the default thickness of drywall for most wall applications.
⅝” Drywall – Drywall of this thickness will usually be made in a fire resistant form since it is mostly used on ceilings and in garages.
Heat and flame rise vertically, and so the ceiling of a garage receives more heat more rapidly. When habitable space is built over the garage, the ceiling of the garage must be protected with 5/8-in. type X gypsum board. Any walls or posts supporting that habitable space must also be protected, but only with 1/2-in.
Because of its moisture resistance, it will fare better in a garage setting where such conditions are common. Plywood, when applied to the walls of your garage, acts as an additional soundproofing and insulating barrier. You may paint or stain the plywood to improve the appearance and make the walls simpler to clean.
Generally speaking, drywall screws should be placed 8-16 inches apart on each side of a 4×8-foot sheet of drywall. If using a larger sheet of drywall, such as a 4×10 or 4×12, then the screws should be spaced 10-20 inches apart.
Drywall absorbs moisture. If drywall sits directly on a concrete floor, it will wick up any moisture that is present in the floor, either now or in the future. Wet drywall has the potential to rot and flake apart. It also provides an ideal space for mold to grow.
One key difference between the two is that sheetrock is a brand name of drywall made by the United States Gypsum Corporation. Another difference lies in their production process; sheetrock has a slightly denser core than drywall due to the addition of a small amount of wood fiber to the gypsum core.