diff --git a/klamath/elements.py b/klamath/elements.py
index ba72d47..9a12b7d 100644
--- a/klamath/elements.py
+++ b/klamath/elements.py
@@ -319,9 +319,9 @@ class Path(Element):
         if self.path_type == 4:
             bgn_ext, end_ext = self.extension
             if bgn_ext != 0:
-                b += BGNEXTN.write(stream, bgn_ext)
+                b += BGNEXTN.write(stream, int(bgn_ext))
             if end_ext != 0:
-                b += ENDEXTN.write(stream, end_ext)
+                b += ENDEXTN.write(stream, int(end_ext))
         b += XY.write(stream, self.xy)
         b += write_properties(stream, self.properties)
         b += ENDEL.write(stream, None)