diff --git a/region.cpp b/region.cpp
index a1f4048a..5338afb4 100644
--- a/region.cpp
+++ b/region.cpp
@@ -29,7 +29,7 @@ using namespace util;
 
 
 template <typename T>
-region<T>::region (T _x, T _y, T _w, T _h):
+region<T>::region (T _x, T _y, size_type _w, size_type _h):
     x (_x),
     y (_y),
     w (_w),
@@ -49,15 +49,15 @@ region<T>::operator+= (const vector<2> &rhs) {
 
 
 template <typename T>
-T 
+typename region<T>::size_type
 region<T>::area (void) const
     { return w * h; }
 
 
 template <typename T>
-T 
+typename region<T>::size_type
 region<T>::diameter (void) const {
-    return (T)sqrt (w * w + h * h);
+    return static_cast<size_type> (sqrt (w * w + h * h));
 }
 
 
diff --git a/region.hpp b/region.hpp
index 6d5e84d7..3aa6ce10 100644
--- a/region.hpp
+++ b/region.hpp
@@ -22,6 +22,7 @@
 #define __UTIL_REGION_HPP
 
 #include "point.hpp"
+#include "types/traits.hpp"
 
 namespace util {
     /**
@@ -29,15 +30,17 @@ namespace util {
      */
     template <typename T>
     struct region {
-        T x, y;
-        T w, h;
+        typedef typename always_unsigned<T>::type size_type;
 
-        region (T _x, T _y, T _w, T _h);
+        T x, y;                 
+        size_type w, h;
+
+        region (T _x, T _y, size_type _w, size_type _h);
 
         region& operator +=(const vector<2>& rhs);
 
-        T area     (void) const;
-        T diameter (void) const;
+        size_type area     (void) const;
+        size_type diameter (void) const;
 
         bool empty (void) const;