How long does expanding foam take to cure?
Short answer
tack-free 10-15 min, cut in 1 h
Expanding foam is tack-free in 10-15 minutes, cuttable in about an hour, and fully cured in 12-24 hours.
What changes the time
| Condition | Time | Why |
|---|---|---|
| for a thick bead | up to 24 hours | Thick foam cures slowly in the middle. |
| in very dry air | slower | Foam cures with moisture, so dry conditions slow it. |
Tips
- Lightly mist the gap with water first to speed curing.
FAQ
When can I trim expanding foam?
Usually after about an hour once it is firm.