diff --git a/src/js/game/building_codes.js b/src/js/game/building_codes.js
index 78240c31..5e2b717b 100644
--- a/src/js/game/building_codes.js
+++ b/src/js/game/building_codes.js
@@ -19,7 +19,7 @@ import { Vector } from "../core/vector";
 
 /**
  * Stores a lookup table for all building variants (for better performance)
- * @type {Object<number, BuildingVariantIdentifier>}
+ * @type {Object<number|string, BuildingVariantIdentifier>}
  */
 export const gBuildingVariants = {
     // Set later
@@ -27,13 +27,13 @@ export const gBuildingVariants = {
 
 /**
  * Mapping from 'metaBuildingId/variant/rotationVariant' to building code
- * @type {Map<string, number>}
+ * @type {Map<string, number|string>}
  */
 const variantsCache = new Map();
 
 /**
  * Registers a new variant
- * @param {number} code
+ * @param {number|string} code
  * @param {typeof MetaBuilding} meta
  * @param {string} variant
  * @param {number} rotationVariant
@@ -54,9 +54,20 @@ export function registerBuildingVariant(
     };
 }
 
+/**
+ * Hashes the combination of buildng, variant and rotation variant
+ * @param {string} buildingId
+ * @param {string} variant
+ * @param {number} rotationVariant
+ * @returns
+ */
+function generateBuildingHash(buildingId, variant, rotationVariant) {
+    return buildingId + "/" + variant + "/" + rotationVariant;
+}
+
 /**
  *
- * @param {number} code
+ * @param {string|number} code
  * @returns {BuildingVariantIdentifier}
  */
 export function getBuildingDataFromCode(code) {
@@ -70,8 +81,8 @@ export function getBuildingDataFromCode(code) {
 export function buildBuildingCodeCache() {
     for (const code in gBuildingVariants) {
         const data = gBuildingVariants[code];
-        const hash = data.metaInstance.getId() + "/" + data.variant + "/" + data.rotationVariant;
-        variantsCache.set(hash, +code);
+        const hash = generateBuildingHash(data.metaInstance.getId(), data.variant, data.rotationVariant);
+        variantsCache.set(hash, isNaN(+code) ? code : +code);
     }
 }
 
@@ -80,10 +91,10 @@ export function buildBuildingCodeCache() {
  * @param {MetaBuilding} metaBuilding
  * @param {string} variant
  * @param {number} rotationVariant
- * @returns {number}
+ * @returns {number|string}
  */
 export function getCodeFromBuildingData(metaBuilding, variant, rotationVariant) {
-    const hash = metaBuilding.getId() + "/" + variant + "/" + rotationVariant;
+    const hash = generateBuildingHash(metaBuilding.getId(), variant, rotationVariant);
     const result = variantsCache.get(hash);
     if (G_IS_DEV) {
         if (!result) {
diff --git a/src/js/game/components/static_map_entity.js b/src/js/game/components/static_map_entity.js
index c76a298e..a3d6a8ca 100644
--- a/src/js/game/components/static_map_entity.js
+++ b/src/js/game/components/static_map_entity.js
@@ -19,7 +19,7 @@ export class StaticMapEntityComponent extends Component {
             originalRotation: types.float,
 
             // See building_codes.js
-            code: types.uint,
+            code: types.uintOrString,
         };
     }
 
@@ -99,7 +99,7 @@ export class StaticMapEntityComponent extends Component {
      * @param {Vector=} param0.tileSize Size of the entity in tiles
      * @param {number=} param0.rotation Rotation in degrees. Must be multiple of 90
      * @param {number=} param0.originalRotation Original Rotation in degrees. Must be multiple of 90
-     * @param {number=} param0.code Building code
+     * @param {number|string=} param0.code Building code
      */
     constructor({
         origin = new Vector(),
diff --git a/src/js/savegame/serialization.js b/src/js/savegame/serialization.js
index 78642ceb..9a0ce3a5 100644
--- a/src/js/savegame/serialization.js
+++ b/src/js/savegame/serialization.js
@@ -22,6 +22,7 @@ import {
     TypeString,
     TypeStructuredObject,
     TypeVector,
+    TypePositiveIntegerOrString,
 } from "./serialization_data_types";
 
 const logger = createLogger("serialization");
@@ -38,6 +39,7 @@ export const types = {
     vector: new TypeVector(),
     tileVector: new TypeVector(),
     bool: new TypeBoolean(),
+    uintOrString: new TypePositiveIntegerOrString(),
 
     /**
      * @param {BaseDataType} wrapped
diff --git a/src/js/savegame/serialization_data_types.js b/src/js/savegame/serialization_data_types.js
index 9d3b689f..df352e78 100644
--- a/src/js/savegame/serialization_data_types.js
+++ b/src/js/savegame/serialization_data_types.js
@@ -213,6 +213,53 @@ export class TypePositiveInteger extends BaseDataType {
     }
 }
 
+export class TypePositiveIntegerOrString extends BaseDataType {
+    serialize(value) {
+        if (Number.isInteger(value)) {
+            assert(value >= 0, "type integer got negative value: " + value);
+        } else if (typeof value === "string") {
+            // all good
+        } else {
+            assertAlways(false, "Type integer|string got non integer or string for serialize: " + value);
+        }
+        return value;
+    }
+
+    /**
+     * @see BaseDataType.deserialize
+     * @param {any} value
+     * @param {GameRoot} root
+     * @param {object} targetObject
+     * @param {string|number} targetKey
+     * @returns {string|void} String error code or null on success
+     */
+    deserialize(value, targetObject, targetKey, root) {
+        targetObject[targetKey] = value;
+    }
+
+    getAsJsonSchemaUncached() {
+        return {
+            oneOf: [{ type: "integer", minimum: 0 }, { type: "string" }],
+        };
+    }
+
+    verifySerializedValue(value) {
+        if (Number.isInteger(value)) {
+            if (value < 0) {
+                return "Negative value for positive integer";
+            }
+        } else if (typeof value === "string") {
+            // all good
+        } else {
+            return "Not a valid number or string: " + value;
+        }
+    }
+
+    getCacheKey() {
+        return "uint_str";
+    }
+}
+
 export class TypeBoolean extends BaseDataType {
     serialize(value) {
         assert(value === true || value === false, "Type bool got non bool for serialize: " + value);