diff --git a/src/p_mobj.c b/src/p_mobj.c
index 4fe59bfab..cd9d36089 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -4077,6 +4077,7 @@ static void P_PlayerMobjThinker(mobj_t *mobj)
 		// Crumbling platforms
 		for (node = mobj->touching_sectorlist; node; node = node->m_snext)
 		{
+			fixed_t topheight, bottomheight;
 			ffloor_t *rover;
 
 			for (rover = node->m_sector->ffloors; rover; rover = rover->next)
@@ -4084,8 +4085,11 @@ static void P_PlayerMobjThinker(mobj_t *mobj)
 				if (!(rover->flags & FF_EXISTS) || !(rover->flags & FF_CRUMBLE))
 					continue;
 
-				if ((*rover->topheight == mobj->z && !(mobj->eflags & MFE_VERTICALFLIP))
-				|| (*rover->bottomheight == mobj->z + mobj->height && mobj->eflags & MFE_VERTICALFLIP)) // You nut.
+				topheight = P_GetFOFTopZ(mobj, node->m_sector, rover, mobj->x, mobj->y, NULL);
+				bottomheight = P_GetFOFBottomZ(mobj, node->m_sector, rover, mobj->x, mobj->y, NULL);
+
+				if ((topheight <= mobj->z + 16*mobj->scale && topheight >= mobj->z && !(mobj->eflags & MFE_VERTICALFLIP))
+				|| (bottomheight >= mobj->z + mobj->height && bottomheight <= mobj->z + mobj->height - 16*mobj->scale && mobj->eflags & MFE_VERTICALFLIP)) // You nut.
 					EV_StartCrumble(rover->master->frontsector, rover, (rover->flags & FF_FLOATBOB), mobj->player, rover->alpha, !(rover->flags & FF_NORETURN));
 			}
 		}