diff --git a/app/constants.ts b/app/constants.ts
index d26b8a7e..6729ba5a 100644
--- a/app/constants.ts
+++ b/app/constants.ts
@@ -111,6 +111,8 @@ const constants: AppConfig = {
   },
 };
 
+export const BODY_TILE_RADIUS = 5;
+
 export const BUILDING_WINDOW_WIDTH = 800;
 export const BUILDING_WINDOW_SCROLL = 400;
 export const BUILDING_WINDOW_SCROLL_SMALL = 200;
diff --git a/app/helpers/rearrangeBuildings.ts b/app/helpers/rearrangeBuildings.ts
index 2175fea7..0a05b06d 100644
--- a/app/helpers/rearrangeBuildings.ts
+++ b/app/helpers/rearrangeBuildings.ts
@@ -1,21 +1,28 @@
 import _ from 'lodash';
 import { types } from '@tlecommunity/client';
 import { BuildingCoordinates, Matrix } from 'app/interfaces/rearrangeBuildings';
+import * as util from 'app/util';
+import { BODY_TILE_RADIUS } from 'app/constants';
 
 type Buildings = types.Body.GetBuildingsResponse['buildings'];
 type Arrangement = types.Body.RearrangeBuildingsParams['arrangement'];
 
-//
-// Pure translations between the server's building map and the 11x11 grid the rearrange window
-// edits. These moved here from app/services when that layer was replaced by app/queries.
-//
+const createEmptyMatrix = (): Matrix => {
+  // Ensure x columns are populated so that we don't get index access errors
+  const matrix: Matrix = [];
+
+  for (let i = 0 - BODY_TILE_RADIUS; i <= BODY_TILE_RADIUS; i++) {
+    matrix[i] = [];
+  }
+
+  return matrix;
+};
 
 export const buildingsToMatrix = (buildings: Buildings): Matrix => {
-  const matrix: Matrix = [];
+  const matrix: Matrix = createEmptyMatrix();
 
   _.each(buildings, (building) => {
-    matrix[building.x] ||= [];
-    matrix[building.x][building.y] = building;
+    matrix[util.int(building.x)][util.int(building.y)] = building;
   });
 
   return matrix;