I'm finishing off a bedroom renovation and just applied the first coat of joint compound to some patches. Want to know the actual drying time before I can sand and apply the next coat. Does it depend on humidity or room temperature?
The biggest thing is that standard joint compound usually needs 24 hours between coats, but humidity and temperature absolutely matter - high humidity can stretch that to 48 hours or more, while dry warm conditions might let you go faster. Are you using regular all-purpose mud or a quick-set product, and what's your room humidity like?
I've learned this the hard way - joint compound dries way slower than you'd think, especially if your bedroom isn't getting good air circulation. Most standard stuff needs a solid 24 hours minimum, but humidity really does kill the timeline; if it's sticky and damp where you are, you might be looking at 36-48 hours before it's actually ready to sand.
The sneaky part that catches people is that it can *feel* dry on the surface while still being soft underneath, so if you sand too early you'll just gunk up your sandpaper and end up with a mess.
Keep a fan going in there and crack a window if you can - that'll help way more than just waiting.
Joint compound gets rock hard when it's fully cured, not just surface-dry - the trick is to put your hand on it and feel if it's still cool to the touch, because that means moisture is still escaping; once it feels room temperature all the way through, you're good to coat again, which typically takes 24 hours but can stretch to 48 in humid conditions. If you're impatient, crack a window or run a fan in that room - air movement cuts drying time noticeably, and I've found that even a cheap box fan pointing at the wall makes a real difference between "maybe today" and "definitely tomorrow.
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