以下详细说明暂以英文提供。
Sheets, seams, and why the number rounds up
Drywall is sold in whole sheets, so the answer always rounds up — there is no such thing as 0.75 of a panel. The waste allowance covers cut-offs around doors and windows, broken corners, and the offcuts that never quite fit anywhere else. Ten percent is the usual planning figure for a plain rectangular room; complicated ceilings, many openings, or diagonal walls can push it to fifteen.
Choosing a sheet length
All three sizes are four feet wide, so the choice is about seam count, not coverage per hour of taping. Long walls that match a sheet length exactly — a 12-foot wall with 4×12 panels — finish with a single horizontal seam and less mudding. The trade-off is handling: a 4×12 sheet is awkward solo and often will not turn in a hallway, which is why 4×8 remains the default for most rooms.
中国本地参考
日常计算时值得知道的中国本地规则：
- 计量的单位习惯: 住房面积用平方米，土地常用亩（1 亩 ≈ 666.7 平方米）；里程用公里，油耗用 L/100km。
- 日期与数字格式: 日期写作 2026年10月13日（年-月-日）；大数习惯用万、亿（1 万 = 10,000，1 亿 = 100,000,000）。
- 法定节假日: 全年法定节假日 11 天，春节与国庆为长假；调休安排每年由国务院办公厅发布。
- 速度与限速: 高速公路最高限速 120 km/h，城市快速路多为 80 km/h，均以公里每小时计。
- 鞋服尺码: 鞋码用中国码（毫米制），服装常用 155/80A 这类身高围度组合，与欧美码不同。
数据核对：2026 年 10 月
常见问题
How do I include the ceiling?
Measure the floor and add that area to your wall total before entering it — a 12×15 room contributes another 180 ft². Many people board ceilings with the same sheet size as the walls.
What waste percentage should I use?
Ten percent is a safe default for typical rooms. Simple garages and basements with few openings can drop to five, while rooms with lots of angles, bulkheads, or window cutouts are happier at fifteen.
Does the cost include tape, mud, and screws?
No — the price row multiplies sheets by your per-sheet price only. A common rule of thumb adds about 15–20% to the board cost for joint compound, tape, fasteners, and corner bead.