diff --git a/src/app-storage/app-storage.service.ts b/src/app-storage/app-storage.service.ts
index 0033827..4de9203 100644
--- a/src/app-storage/app-storage.service.ts
+++ b/src/app-storage/app-storage.service.ts
@@ -114,7 +114,13 @@ export class AppStorageService {
 
     set.storages = [...(set.storages || []), storage];
 
-    return this.formatStorageSetNoItems(set);
+    // Remove circular set reference
+    const respondWith = {
+      ...set,
+      storages: set.storages.map((storage) => omit(storage, ['set'])),
+    };
+
+    return this.formatStorageSetNoItems(respondWith);
   }
 
   async removeFromSet(set: StorageSet, storage: Storage) {
@@ -421,7 +427,7 @@ export class AppStorageService {
       ...omit(storage, ['room', 'set']),
       items: !!storage.items?.length
         ? storage.items.map((item) => this.formatStoredItem(item))
-        : null,
+        : [],
       addedBy: storage.addedBy && this.formatActor(storage.addedBy),
     };
   }
diff --git a/src/objects/building/building.module.ts b/src/objects/building/building.module.ts
index fb29785..5816a51 100644
--- a/src/objects/building/building.module.ts
+++ b/src/objects/building/building.module.ts
@@ -5,9 +5,18 @@ import { Building } from './entities/building.entity';
 import { BuildingService } from './building.service';
 import { Floor } from './entities/floor.entity';
 import { Room } from './entities/room.entity';
+import { UserBuildingAccessControl } from './entities/acl.entity';
 
 @Module({
-  imports: [GroupModule, TypeOrmModule.forFeature([Building, Floor, Room])],
+  imports: [
+    GroupModule,
+    TypeOrmModule.forFeature([
+      Building,
+      Floor,
+      Room,
+      UserBuildingAccessControl,
+    ]),
+  ],
   providers: [BuildingService],
   exports: [TypeOrmModule, BuildingService],
 })
diff --git a/src/objects/building/building.service.ts b/src/objects/building/building.service.ts
index 67c6df0..2192f02 100644
--- a/src/objects/building/building.service.ts
+++ b/src/objects/building/building.service.ts
@@ -2,6 +2,7 @@ import { Injectable } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import { Repository } from 'typeorm';
 import { GroupService } from '../group/group.service';
+import { UserBuildingAccessControl } from './entities/acl.entity';
 import { Building } from './entities/building.entity';
 import { Floor } from './entities/floor.entity';
 import { Room } from './entities/room.entity';
@@ -15,6 +16,8 @@ export class BuildingService {
     private readonly floorRepository: Repository<Floor>,
     @InjectRepository(Room)
     private readonly roomRepository: Repository<Room>,
+    @InjectRepository(UserBuildingAccessControl)
+    private readonly aclRepository: Repository<UserBuildingAccessControl>,
     private readonly groupService: GroupService,
   ) {}
 
diff --git a/src/objects/building/entities/acl.entity.ts b/src/objects/building/entities/acl.entity.ts
new file mode 100644
index 0000000..ec253b9
--- /dev/null
+++ b/src/objects/building/entities/acl.entity.ts
@@ -0,0 +1,37 @@
+import { ApiProperty } from '@nestjs/swagger';
+import { User } from 'src/objects/user/user.entity';
+import { Building } from 'src/objects/building/entities/building.entity';
+import { Column, Entity, ManyToOne, PrimaryGeneratedColumn } from 'typeorm';
+import { Group } from 'src/objects/group/group.entity';
+import { Access } from 'src/objects/enums/access-control.enum';
+
+@Entity()
+export class UserBuildingAccessControl {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @ApiProperty({ type: () => User })
+  @ManyToOne(() => User, {
+    onDelete: 'CASCADE',
+    onUpdate: 'CASCADE',
+  })
+  user: User;
+
+  @ApiProperty({ type: () => Building })
+  @ManyToOne(() => Building, {
+    onDelete: 'CASCADE',
+    onUpdate: 'CASCADE',
+  })
+  building: Building;
+
+  @ApiProperty({ type: () => Group })
+  @ManyToOne(() => Group, {
+    onDelete: 'CASCADE',
+    onUpdate: 'CASCADE',
+  })
+  group: Group;
+
+  @ApiProperty({ enum: Access })
+  @Column({ type: String })
+  access: Access;
+}
diff --git a/src/objects/enums/access-control.enum.ts b/src/objects/enums/access-control.enum.ts
new file mode 100644
index 0000000..e648ec3
--- /dev/null
+++ b/src/objects/enums/access-control.enum.ts
@@ -0,0 +1,8 @@
+export enum Access {
+  ADMIN = 'ADMIN',
+  EDIT_FLOOR_PLAN = 'EDIT_FLOOR_PLAN',
+  MANAGE_STORAGE = 'MANAGE_STORAGE',
+  MANAGE_ACCESS = 'MANAGE_ACCESS',
+  MANAGE_FINANCE = 'MANAGE_FINANCE',
+  TODOLIST = 'TODOLIST',
+}