--- a/testing/mozharness/configs/builds/releng_base_windows_32_builds.py
+++ b/testing/mozharness/configs/builds/releng_base_windows_32_builds.py
@@ -75,16 +75,18 @@ config = {
         'MOZ_CRASHREPORTER_NO_REPORT': '1',
         'MOZ_OBJDIR': 'obj-firefox',
         'PATH': 'C:/mozilla-build/nsis-3.0b1;C:/mozilla-build/python27;'
                 'C:/mozilla-build/buildbotve/scripts;'
                 '%s' % (os.environ.get('path')),
         'PDBSTR_PATH': '/c/Program Files (x86)/Windows Kits/8.0/Debuggers/x64/srcsrv/pdbstr.exe',
         'PROPERTIES_FILE': os.path.join(os.getcwd(), 'buildprops.json'),
         'TINDERBOX_OUTPUT': '1',
+        'TOOLTOOL_CACHE': '/c/builds/tooltool_cache',
+        'TOOLTOOL_HOME': '/c/builds',
     },
     'upload_env': {
         # stage_server is dictated from build_pool_specifics.py
         'UPLOAD_HOST': '%(stage_server)s',
         'UPLOAD_USER': '%(stage_username)s',
         'UPLOAD_SSH_KEY': '/c/Users/cltbld/.ssh/%(stage_ssh_key)s',
         'UPLOAD_TO_TEMP': '1',
     },

--- a/testing/mozharness/configs/builds/releng_base_windows_64_builds.py
+++ b/testing/mozharness/configs/builds/releng_base_windows_64_builds.py
@@ -73,16 +73,18 @@ config = {
         'MOZ_CRASHREPORTER_NO_REPORT': '1',
         'MOZ_OBJDIR': 'obj-firefox',
         'PATH': 'C:/mozilla-build/nsis-3.0b1;C:/mozilla-build/python27;'
                 'C:/mozilla-build/buildbotve/scripts;'
                 '%s' % (os.environ.get('path')),
         'PDBSTR_PATH': '/c/Program Files (x86)/Windows Kits/8.0/Debuggers/x64/srcsrv/pdbstr.exe',
         'PROPERTIES_FILE': os.path.join(os.getcwd(), 'buildprops.json'),
         'TINDERBOX_OUTPUT': '1',
+        'TOOLTOOL_CACHE': '/c/builds/tooltool_cache',
+        'TOOLTOOL_HOME': '/c/builds',
     },
     'upload_env': {
         # stage_server is dictated from build_pool_specifics.py
         'UPLOAD_HOST': '%(stage_server)s',
         'UPLOAD_USER': '%(stage_username)s',
         'UPLOAD_SSH_KEY': '/c/Users/cltbld/.ssh/%(stage_ssh_key)s',
         'UPLOAD_TO_TEMP': '1',
     },

--- a/testing/mozharness/configs/builds/releng_sub_windows_configs/32_debug.py
+++ b/testing/mozharness/configs/builds/releng_sub_windows_configs/32_debug.py
@@ -27,12 +27,14 @@ config = {
         'MOZ_CRASHREPORTER_NO_REPORT': '1',
         'MOZ_OBJDIR': 'obj-firefox',
         'PATH': 'C:/mozilla-build/nsis-3.0b1;C:/mozilla-build/python27;'
                 'C:/mozilla-build/buildbotve/scripts;'
                 '%s' % (os.environ.get('path')),
         'PROPERTIES_FILE': os.path.join(os.getcwd(), 'buildprops.json'),
         'TINDERBOX_OUTPUT': '1',
         'XPCOM_DEBUG_BREAK': 'stack-and-abort',
+        'TOOLTOOL_CACHE': '/c/builds/tooltool_cache',
+        'TOOLTOOL_HOME': '/c/builds',
     },
     'src_mozconfig': 'browser/config/mozconfigs/win32/debug',
     #######################
 }

--- a/testing/mozharness/configs/builds/releng_sub_windows_configs/32_mulet.py
+++ b/testing/mozharness/configs/builds/releng_sub_windows_configs/32_mulet.py
@@ -26,12 +26,14 @@ config = {
         'MOZ_CRASHREPORTER_NO_REPORT': '1',
         'MOZ_OBJDIR': 'obj-firefox',
         'PATH': 'C:/mozilla-build/nsis-3.0b1;C:/mozilla-build/python27;'
                 'C:/mozilla-build/buildbotve/scripts;'
                 '%s' % (os.environ.get('path')),
         'PROPERTIES_FILE': os.path.join(os.getcwd(), 'buildprops.json'),
         'TINDERBOX_OUTPUT': '1',
         'XPCOM_DEBUG_BREAK': 'stack-and-abort',
+        'TOOLTOOL_CACHE': '/c/builds/tooltool_cache',
+        'TOOLTOOL_HOME': '/c/builds',
     },
     'src_mozconfig': 'b2g/dev/config/mozconfigs/win32/mulet',
     #######################
 }

--- a/testing/mozharness/configs/builds/releng_sub_windows_configs/32_stat_and_debug.py
+++ b/testing/mozharness/configs/builds/releng_sub_windows_configs/32_stat_and_debug.py
@@ -30,13 +30,15 @@ clang.manifest",
         'MOZ_CRASHREPORTER_NO_REPORT': '1',
         'MOZ_OBJDIR': 'obj-firefox',
         'PATH': 'C:/mozilla-build/nsis-3.0a2;C:/mozilla-build/nsis-2.46u;C:/mozilla-build/python27;'
                 'C:/mozilla-build/buildbotve/scripts;'
                 '%s' % (os.environ.get('path')),
         'PROPERTIES_FILE': os.path.join(os.getcwd(), 'buildprops.json'),
         'TINDERBOX_OUTPUT': '1',
         'XPCOM_DEBUG_BREAK': 'stack-and-abort',
+        'TOOLTOOL_CACHE': '/c/builds/tooltool_cache',
+        'TOOLTOOL_HOME': '/c/builds',
     },
     'src_mozconfig': 'browser/config/mozconfigs/win32/debug-static-analysis',
     'purge_minsize': 9,
     #######################
 }

--- a/testing/mozharness/configs/builds/releng_sub_windows_configs/64_debug.py
+++ b/testing/mozharness/configs/builds/releng_sub_windows_configs/64_debug.py
@@ -26,12 +26,14 @@ config = {
         'MOZ_CRASHREPORTER_NO_REPORT': '1',
         'MOZ_OBJDIR': 'obj-firefox',
         'PATH': 'C:/mozilla-build/nsis-3.0b1;C:/mozilla-build/python27;'
                 'C:/mozilla-build/buildbotve/scripts;'
                 '%s' % (os.environ.get('path')),
         'PROPERTIES_FILE': os.path.join(os.getcwd(), 'buildprops.json'),
         'TINDERBOX_OUTPUT': '1',
         'XPCOM_DEBUG_BREAK': 'stack-and-abort',
+        'TOOLTOOL_CACHE': '/c/builds/tooltool_cache',
+        'TOOLTOOL_HOME': '/c/builds',
     },
     'src_mozconfig': 'browser/config/mozconfigs/win64/debug',
     #######################
 }

--- a/testing/mozharness/configs/builds/releng_sub_windows_configs/64_graphene.py
+++ b/testing/mozharness/configs/builds/releng_sub_windows_configs/64_graphene.py
@@ -26,13 +26,15 @@ config = {
         'MOZ_CRASHREPORTER_NO_REPORT': '1',
         'MOZ_OBJDIR': 'obj-graphene',
         'PATH': 'C:/mozilla-build/nsis-3.0b1;C:/mozilla-build/python27;'
                 'C:/mozilla-build/buildbotve/scripts;'
                 '%s' % (os.environ.get('path')),
         'PROPERTIES_FILE': os.path.join(os.getcwd(), 'buildprops.json'),
         'TINDERBOX_OUTPUT': '1',
         'XPCOM_DEBUG_BREAK': 'stack-and-abort',
+        'TOOLTOOL_CACHE': '/c/builds/tooltool_cache',
+        'TOOLTOOL_HOME': '/c/builds',
     },
     'src_mozconfig': 'b2g/graphene/config/mozconfigs/win64/nightly',
     'balrog_platform': 'win64',
     #######################
 }

--- a/testing/mozharness/configs/builds/releng_sub_windows_configs/64_horizon.py
+++ b/testing/mozharness/configs/builds/releng_sub_windows_configs/64_horizon.py
@@ -26,13 +26,15 @@ config = {
         'MOZ_CRASHREPORTER_NO_REPORT': '1',
         'MOZ_OBJDIR': 'obj-horizon',
         'PATH': 'C:/mozilla-build/nsis-3.0b1;C:/mozilla-build/python27;'
                 'C:/mozilla-build/buildbotve/scripts;'
                 '%s' % (os.environ.get('path')),
         'PROPERTIES_FILE': os.path.join(os.getcwd(), 'buildprops.json'),
         'TINDERBOX_OUTPUT': '1',
         'XPCOM_DEBUG_BREAK': 'stack-and-abort',
+        'TOOLTOOL_CACHE': '/c/builds/tooltool_cache',
+        'TOOLTOOL_HOME': '/c/builds',
     },
     'src_mozconfig': 'b2g/graphene/config/horizon-mozconfigs/win64/nightly',
     'balrog_platform': 'win64',
     #######################
 }

--- a/testing/mozharness/mozharness/mozilla/building/buildbase.py
+++ b/testing/mozharness/mozharness/mozilla/building/buildbase.py
@@ -1127,16 +1127,19 @@ or run without that action (ie: --no-{ac
             tooltool_manifest_path,
             c['tooltool_url'],
             c['tooltool_bootstrap'],
         ]
         cmd.extend(c['tooltool_script'])
         auth_file = self._get_tooltool_auth_file()
         if auth_file:
             cmd.extend(['--authentication-file', auth_file])
+        cache = c['env'].get('TOOLTOOL_CACHE')
+        if cache:
+            cmd.extend(['-c', cache])
         self.info(str(cmd))
         self.run_command_m(cmd, cwd=dirs['abs_src_dir'], halt_on_failure=True)
 
     def query_revision(self, source_path=None):
         """ returns the revision of the build
 
          first will look for it in buildbot_properties and then in
          buildbot_config. Failing that, it will actually poll the source of