Large-scale retailers are the most common source for joint compound. They typically stock a variety of formats, including small tubs for patches and large 4.5-gallon buckets for full-room finishing.
If you aren't in a rush, joint compound can be ordered online, though shipping costs can be high due to the weight.
For large-scale renovations or professional use, specialized building material suppliers often offer better bulk rates and higher-quality specialty muds.
: Typically carries standard sizes like the 3.5-quart premixed tubs for minor repairs. Specialized Supply Houses