diff --git a/src/lighting/Lightmap.cpp b/src/lighting/Lightmap.cpp
index cb077b8b..24581e24 100644
--- a/src/lighting/Lightmap.cpp
+++ b/src/lighting/Lightmap.cpp
@@ -2,16 +2,15 @@
 
 #include "util/data_io.hpp"
 
-#include <assert.h>
+#include <cassert>
+#include <cstring>
 
 void Lightmap::set(const Lightmap* lightmap) {
     set(lightmap->map);
 }
 
 void Lightmap::set(const light_t* map) {
-    for (size_t i = 0; i < CHUNK_VOL; i++) {
-        this->map[i] = map[i];
-    }
+    std::memcpy(this->map, map, sizeof(light_t) * CHUNK_VOL);
 }
 
 static_assert(sizeof(light_t) == 2, "replace dataio calls to new light_t");
diff --git a/src/util/WeakPtrsMap.hpp b/src/util/WeakPtrsMap.hpp
new file mode 100644
index 00000000..0d206d65
--- /dev/null
+++ b/src/util/WeakPtrsMap.hpp
@@ -0,0 +1,43 @@
+#include <mutex>
+#include <memory>
+#include <unordered_map>
+
+namespace util {
+    template <typename K, typename V>
+    class WeakPtrsMap {
+        std::unordered_map<K, std::weak_ptr<V>> map;
+        std::mutex mutex;
+    public:
+        std::weak_ptr<V>& operator[](const K& k) {
+            return map[k];
+        }
+
+        std::shared_ptr<V> fetch(const K& k) {
+            auto found = map.find(k);
+            if (found == map.end()) {
+                return nullptr;
+            }
+            auto ptr = found->second.lock();
+            if (ptr == nullptr) {
+                map.erase(found);
+            }
+            return ptr;
+        }
+
+        void erase(const K& k) {
+            map.erase(k);
+        }
+
+        size_t size() const {
+            return map.size();
+        }
+
+        void lock() {
+            mutex.lock();
+        }
+
+        void unlock() {
+            mutex.unlock();
+        }
+    };
+}
diff --git a/src/voxels/ChunksStorage.cpp b/src/voxels/ChunksStorage.cpp
index 26b4fbd3..60e3b544 100644
--- a/src/voxels/ChunksStorage.cpp
+++ b/src/voxels/ChunksStorage.cpp
@@ -17,34 +17,28 @@
 
 static debug::Logger logger("chunks-storage");
 
-ChunksStorage::ChunksStorage(Level* level) : level(level) {
+ChunksStorage::ChunksStorage(Level* level)
+    : level(level),
+      chunksMap(std::make_shared<util::WeakPtrsMap<glm::ivec2, Chunk>>()) {
 }
 
 std::shared_ptr<Chunk> ChunksStorage::fetch(int x, int z) {
-    std::lock_guard lock(mutex);
-
-    auto found = chunksMap.find(glm::ivec2(x, z));
-    if (found == chunksMap.end()) {
-        return nullptr;
-    }
-    auto ptr = found->second.lock();
-    if (ptr == nullptr) {
-        chunksMap.erase(found);
-    }
-    return ptr;
+    std::lock_guard lock(*chunksMap);
+    return chunksMap->fetch({x, z});
 }
 
-static void check_voxels(const ContentIndices& indices, Chunk* chunk) {
+static void check_voxels(const ContentIndices& indices, Chunk& chunk) {
     bool corrupted = false;
+    blockid_t defsCount = indices.blocks.count();
     for (size_t i = 0; i < CHUNK_VOL; i++) {
-        blockid_t id = chunk->voxels[i].id;
-        if (indices.blocks.get(id) == nullptr) {
+        blockid_t id = chunk.voxels[i].id;
+        if (id >= defsCount) {
             if (!corrupted) {
 #ifdef NDEBUG
                 // release
                 auto logline = logger.error();
                 logline << "corruped blocks detected at " << i << " of chunk ";
-                logline << chunk->x << "x" << chunk->z;
+                logline << chunk.x << "x" << chunk.z;
                 logline << " -> " << id;
                 corrupted = true;
 #else
@@ -52,33 +46,34 @@ static void check_voxels(const ContentIndices& indices, Chunk* chunk) {
                 abort();
 #endif
             }
-            chunk->voxels[i].id = BLOCK_AIR;
+            chunk.voxels[i].id = BLOCK_AIR;
         }
     }
 }
 
 std::shared_ptr<Chunk> ChunksStorage::create(int x, int z) {
-    std::lock_guard lock(mutex);
-
-    auto found = chunksMap.find(glm::ivec2(x, z));
-    if (found != chunksMap.end()) {
-        auto chunk = found->second.lock();
-        if (chunk) {
-            return chunk;
-        }
+    if (auto ptr = chunksMap->fetch({x, z})) {
+        return ptr;
     }
 
     World* world = level->getWorld();
     auto& regions = world->wfile.get()->getRegions();
 
-    auto chunk = std::make_shared<Chunk>(x, z);
-    chunksMap[glm::ivec2(chunk->x, chunk->z)] = chunk;
+    auto& localChunksMap = chunksMap;
+    auto chunk = std::shared_ptr<Chunk>(
+        new Chunk(x, z),
+        [localChunksMap, x, z](auto ptr) {
+            std::lock_guard lock(*localChunksMap);
+            localChunksMap->erase({x, z});
+            delete ptr;
+        }
+    );
+    (*chunksMap)[glm::ivec2(chunk->x, chunk->z)] = chunk;
     if (auto data = regions.getVoxels(chunk->x, chunk->z)) {
         const auto& indices = *level->content->getIndices();
 
         chunk->decode(data.get());
-        check_voxels(indices, chunk.get());
-
+        check_voxels(indices, *chunk);
         auto invs = regions.fetchInventories(chunk->x, chunk->z);
         auto iterator = invs.begin();
         while (iterator != invs.end()) {
diff --git a/src/voxels/ChunksStorage.hpp b/src/voxels/ChunksStorage.hpp
index 78bc03d0..62cccaf3 100644
--- a/src/voxels/ChunksStorage.hpp
+++ b/src/voxels/ChunksStorage.hpp
@@ -1,19 +1,16 @@
 #pragma once
 
-#include <mutex>
-#include <memory>
-#include <unordered_map>
-
 #define GLM_ENABLE_EXPERIMENTAL
 #include <glm/gtx/hash.hpp>
 
+#include "util/WeakPtrsMap.hpp"
+
 class Chunk;
 class Level;
 
 class ChunksStorage {
     Level* level;
-    std::mutex mutex;
-    std::unordered_map<glm::ivec2, std::weak_ptr<Chunk>> chunksMap;
+    std::shared_ptr<util::WeakPtrsMap<glm::ivec2, Chunk>> chunksMap;
 public:
     ChunksStorage(Level* level);
     ~ChunksStorage() = default;