diff --git a/docs/Lua API.rst b/docs/Lua API.rst
index 28b90f0d0..f9c6c1e60 100644
--- a/docs/Lua API.rst	
+++ b/docs/Lua API.rst	
@@ -1617,12 +1617,13 @@ General
   using width and height for flexible dimensions.
   Returns *is_flexible, width, height, center_x, center_y*.
 
-* ``dfhack.buildings.checkFreeTiles(pos,size[,extents,change_extents,allow_occupied,is_civzone])``
+* ``dfhack.buildings.checkFreeTiles(pos,size[,extents,change_extents,allow_occupied,allow_wall])``
 
   Checks if the rectangle defined by ``pos`` and ``size``, and possibly extents,
   can be used for placing a building. If ``change_extents`` is true, bad tiles
   are removed from extents. If ``allow_occupied``, the occupancy test is skipped.
-  Set ``is_civzone`` to true if the building is a civzone (like an activity zone).
+  Set ``allow_wall`` to true if the building is unhindered by walls (such as an
+  activity zone).
 
 * ``dfhack.buildings.countExtentTiles(extents,defval)``
 
diff --git a/library/include/modules/Buildings.h b/library/include/modules/Buildings.h
index 256e3b7e6..94bf75499 100644
--- a/library/include/modules/Buildings.h
+++ b/library/include/modules/Buildings.h
@@ -143,7 +143,7 @@ DFHACK_EXPORT bool checkFreeTiles(df::coord pos, df::coord2d size,
                                   df::building_extents *ext = NULL,
                                   bool create_ext = false,
                                   bool allow_occupied = false,
-                                  bool is_civzone = false);
+                                  bool allow_wall = false);
 
 /**
  * Returns the number of tiles included by the extent, or defval.
diff --git a/library/modules/Buildings.cpp b/library/modules/Buildings.cpp
index 3d708dc92..976ade441 100644
--- a/library/modules/Buildings.cpp
+++ b/library/modules/Buildings.cpp
@@ -576,7 +576,7 @@ bool Buildings::checkFreeTiles(df::coord pos, df::coord2d size,
                                df::building_extents *ext,
                                bool create_ext,
                                bool allow_occupied,
-                               bool is_civzone)
+                               bool allow_wall)
 {
     bool found_any = false;
 
@@ -611,7 +611,7 @@ bool Buildings::checkFreeTiles(df::coord pos, df::coord2d size,
             else
             {
                 auto tile = block->tiletype[btile.x][btile.y];
-                if (!is_civzone && !HighPassable(tile))
+                if (!allow_wall && !HighPassable(tile))
                     allowed = false;
             }