# Does difficult terrain stack?

I was playing an encounter from the tales from the yawning portal hardcover and in this room every foot of movement is 3 feet of speed. We were bunched up by the door and needed to move through each other. We were not sure what to do for the combination of walking on a slick floor in the same space as an ally. Moving each space in the room was costing 15' of speed. Moving through an allies space would normally cost 10' of speed.

Do you just take the larger of the two effects or stack them?

• Commented Nov 8, 2021 at 23:59

# No, difficult terrain does not stack

Every foot of movement in difficult terrain costs 1 extra foot. This rule is true even if multiple things in a space count as difficult terrain.

An area is difficult terrain or it is not. But there is no area that is more difficult terrain by virtue of having stacking difficult terrain effects in it.

Regardless of the amount of effects that cause difficult terrain in one area, moment costs 1 extra foot per foot of moment.