diff --git a/builder.py b/builder.py
index bb5cadc..5c8b4ea 100644
--- a/builder.py
+++ b/builder.py
@@ -76,7 +76,7 @@ class BuildJob:
                 return self._after2(1)
         state.stamp(dofile)
         unlink(tmpname)
-        ffd = os.open(tmpname, os.O_CREAT|os.O_RDWR|os.O_EXCL)
+        ffd = os.open(tmpname, os.O_CREAT|os.O_RDWR|os.O_EXCL, 0666)
         close_on_exec(ffd, True)
         self.f = os.fdopen(ffd, 'w+')
         # this will run in the dofile's directory, so use only basenames here
diff --git a/t/.gitignore b/t/.gitignore
index 5d5e603..608d5f9 100644
--- a/t/.gitignore
+++ b/t/.gitignore
@@ -7,3 +7,4 @@ d
 test.args
 test2.args
 /passfail
+mode1
diff --git a/t/clean.do b/t/clean.do
index 890b88c..20f1ef3 100644
--- a/t/clean.do
+++ b/t/clean.do
@@ -1,4 +1,4 @@
 redo example/clean curse/clean deps/clean "space dir/clean"
-rm -f c c.c c.c.c c.c.c.b c.c.c.b.b d
+rm -f c c.c c.c.c c.c.c.b c.c.c.b.b d mode1
 rm -f hello [by]ellow *.o *~ .*~ CC LD passfail
 
diff --git a/t/mode1.do b/t/mode1.do
new file mode 100644
index 0000000..2f08be9
--- /dev/null
+++ b/t/mode1.do
@@ -0,0 +1 @@
+echo hello
diff --git a/t/modetest.do b/t/modetest.do
new file mode 100644
index 0000000..a436baf
--- /dev/null
+++ b/t/modetest.do
@@ -0,0 +1,5 @@
+umask 0022
+redo mode1
+MODE="$(ls -l mode1 | cut -d' ' -f1)"
+[ "$MODE" = "-rw-r--r--" ] || exit 78
+
diff --git a/t/test.do b/t/test.do
index ec45825..9b94af4 100644
--- a/t/test.do
+++ b/t/test.do
@@ -1,6 +1,4 @@
 redo-ifchange all
 ./hello >&2
 redo deltest deltest2 test.args test2.args passfailtest \
-	curse/test deps/test "space dir/test"
-
-
+	curse/test deps/test "space dir/test" modetest