diff --git a/doc/manual/command-ref/nix-store.xml b/doc/manual/command-ref/nix-store.xml
index bf12d06f1..2ecc63db7 100644
--- a/doc/manual/command-ref/nix-store.xml
+++ b/doc/manual/command-ref/nix-store.xml
@@ -247,8 +247,15 @@ printed.)</para>
 </variablelist>
 
 <para>With the <option>--keep-going</option> flag it's possible for
-multiple build failures to occur, in this case the 1xx status codes
-are or combined.</para>
+multiple failures to occur, in this case the 1xx status codes are or combined
+using binary or. <screen>
+1100100
+   ^^^^
+   |||`- timeout
+   ||`-- output hash mismatch
+   |`--- build failure
+   `---- not deterministic
+</screen></para>
 
 </refsection>
 
diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index abfae3c7c..350ac4092 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -4471,15 +4471,29 @@ void Worker::waitForInput()
 
 unsigned int Worker::exitStatus()
 {
+    /*
+     * 1100100
+     *    ^^^^
+     *    |||`- timeout
+     *    ||`-- output hash mismatch
+     *    |`--- build failure
+     *    `---- not deterministic
+     */
     unsigned int mask = 0;
+    bool buildFailure = permanentFailure || timedOut || hashMismatch;
+    if (buildFailure)
+        mask |= 0x04;  // 100
     if (timedOut)
-        mask |= 1;
+        mask |= 0x01;  // 101
     if (hashMismatch)
-        mask |= 2;
-    if (checkMismatch)
-        mask |= 4;
+        mask |= 0x02;  // 102
+    if (checkMismatch) {
+        mask |= 0x08;  // 104
+    }
 
-    return mask ? 100 + mask : 1;
+    if (mask)
+        mask |= 0x60;
+    return mask ? mask : 1;
 }
 
 
diff --git a/tests/check.sh b/tests/check.sh
index aa1e5cd26..bc23a6634 100644
--- a/tests/check.sh
+++ b/tests/check.sh
@@ -7,8 +7,8 @@ nix-build dependencies.nix --no-out-link --check
 
 nix-build check.nix -A nondeterministic --no-out-link
 nix-build check.nix -A nondeterministic --no-out-link --check 2> $TEST_ROOT/log || status=$?
-[ "$status" = "104" ]
 grep 'may not be deterministic' $TEST_ROOT/log
+[ "$status" = "104" ]
 
 clearStore
 
@@ -44,4 +44,4 @@ nix-build check.nix -A hashmismatch --no-out-link --check --hashed-mirrors '' ||
 # Multiple failures with --keep-going
 nix-build check.nix -A nondeterministic --no-out-link
 nix-build check.nix -A nondeterministic -A hashmismatch --no-out-link --check --keep-going --hashed-mirrors '' || status=$?
-[ "$status" = "106" ]
+[ "$status" = "110" ]