diff --git a/CMakeLists.txt b/CMakeLists.txt
index 23a96b89f..ab7f415dc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -146,7 +146,8 @@ elseif(${CMAKE_CXX_COMPILER_ID} MATCHES "Clang")
 elseif(MSVC)
   # Visual Studio pedantic build settings
   # warning C4512: assignment operator could not be generated
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4 /WX /wd4512")
+  # warning C4316: object allocated on the heap may not be aligned
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4 /WX /wd4512 /wd4316")
 endif()
 
 if(FLATBUFFERS_CODE_COVERAGE)
diff --git a/include/flatbuffers/flexbuffers.h b/include/flatbuffers/flexbuffers.h
index 2c7a25ec7..3853d50f7 100644
--- a/include/flatbuffers/flexbuffers.h
+++ b/include/flatbuffers/flexbuffers.h
@@ -1281,7 +1281,7 @@ class Builder FLATBUFFERS_FINAL_CLASS {
     // Write vector. First the keys width/offset if available, and size.
     if (keys) {
       WriteOffset(keys->u_, byte_width);
-      Write<uint64_t>(1U << keys->min_bit_width_, byte_width);
+      Write<uint64_t>(1ULL << keys->min_bit_width_, byte_width);
     }
     if (!fixed) Write<uint64_t>(vec_len, byte_width);
     // Then the actual data.