diff --git a/README.rst b/README.rst
index 89f48b741..5ab611f3d 100644
--- a/README.rst
+++ b/README.rst
@@ -86,6 +86,9 @@ To set up a suitable build environment for ``./build.sh``::
 An explanation of this, plus more recipes, can be found on the `sbuild wiki
 page <https://wiki.debian.org/sbuild>`_.
 
+If you need to pass additional options to sbuild, like "--arch=i386", then set
+the SBUILD_OPTS environment variable.
+
 Normally, ``./build.sh`` will fail early if not all the build dependencies are
 available in your local apt cache. If you are packaging a large dependency tree
 however, to avoid many round-trips through NEW it is possible to bypass this
diff --git a/build.sh b/build.sh
index 22b47bfe8..b76e3eb3e 100755
--- a/build.sh
+++ b/build.sh
@@ -14,6 +14,8 @@
 #     Release to something other than unstable, e.g. experimental
 # CHROOT=$chroot
 #     Build using another schroot than debcargo-unstable-amd64-sbuild
+# SBUILD_OPTS=
+#     will pass to sbuild; for example SBUILD_OPTS=--arch=i386
 set -e
 
 SCRIPTDIR="$(dirname $(readlink -f "$0"))"
@@ -154,6 +156,7 @@ SBUILD_CONFIG="$SCRIPTDIR/dev/sbuildrc" sbuild --no-source --arch-any --arch-all
   "${EXTRA_DEBS_AUTOPKGTEST_OPTS[@]}" \
   "${AUTOPKGTEST_OPTS[@]}" \
   "${LINTIAN_OPTS[@]}" \
+   ${SBUILD_OPTS} \
   "$SRCNAME.dsc"
 if [ "$SKIP_AUTOPKGTEST" != 1 ]; then
 	report "analyzing autopkgtest log: $BUILDNAME.test.log"