--- a/taskcluster/ci/build/windows.yml
+++ b/taskcluster/ci/build/windows.yml
@@ -13,16 +13,17 @@ win32/debug:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win32.py
             - builds/taskcluster_sub_win32/debug.py
     toolchains:
         - win32-clang-cl
         - win32-rust
         - win64-sccache
 
 win32/opt:
@@ -40,16 +41,17 @@ win32/opt:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win32.py
             - builds/taskcluster_sub_win32/opt.py
     toolchains:
         - win32-clang-cl
         - win32-rust
         - win64-sccache
 
 win32-dmd/opt:
@@ -67,16 +69,17 @@ win32-dmd/opt:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win32.py
             - builds/taskcluster_sub_win32/opt.py
         custom-build-variant-cfg: dmd
     run-on-projects: []
     toolchains:
         - win32-clang-cl
         - win32-rust
         - win64-sccache
@@ -96,16 +99,17 @@ win32/pgo:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/releng.manifest"
     run:
         using: mozharness
         options: [enable-pgo, append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win32.py
             - builds/taskcluster_sub_win32/opt.py
     toolchains:
         - win32-clang-cl
         - win32-rust
         - win64-sccache
 
 win64/debug:
@@ -123,16 +127,17 @@ win64/debug:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/debug.py
     toolchains:
         - win64-clang-cl
         - win64-rust
         - win64-sccache
 
 win64/opt:
@@ -150,16 +155,17 @@ win64/opt:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/opt.py
     toolchains:
         - win64-clang-cl
         - win64-rust
         - win64-sccache
 
 win64-dmd/opt:
@@ -177,16 +183,17 @@ win64-dmd/opt:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/opt.py
         custom-build-variant-cfg: dmd
     run-on-projects: []
     toolchains:
         - win64-clang-cl
         - win64-rust
         - win64-sccache
@@ -210,16 +217,17 @@ win32-nightly/opt:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/releng.manifest"
     run:
         using: mozharness
         actions: [clone-tools, build, check-test, update]
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win32.py
             - builds/taskcluster_sub_win32/opt.py
             - disable_signing.py
             - taskcluster_nightly.py
     toolchains:
         - win32-clang-cl
         - win32-rust
         - win64-sccache
@@ -243,16 +251,17 @@ win64-nightly/opt:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
     run:
         using: mozharness
         actions: [clone-tools, build, check-test, update]
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/opt.py
             - disable_signing.py
             - taskcluster_nightly.py
     toolchains:
         - win64-clang-cl
         - win64-rust
         - win64-sccache
@@ -272,16 +281,17 @@ win64/pgo:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
     run:
         using: mozharness
         options: [enable-pgo, append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/opt.py
     toolchains:
         - win64-clang-cl
         - win64-rust
         - win64-sccache
 
 win32-add-on-devel/opt:
@@ -299,16 +309,17 @@ win32-add-on-devel/opt:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: "mozharness/scripts/fx_desktop_build.py"
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win32.py
             - builds/taskcluster_sub_win32/addondevel.py
             - balrog/production.py
     run-on-projects: ['mozilla-beta', 'mozilla-release', 'mozilla-esr45']
     toolchains:
         - win32-clang-cl
         - win32-rust
         - win64-sccache
@@ -328,16 +339,17 @@ win64-add-on-devel/opt:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: "mozharness/scripts/fx_desktop_build.py"
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/addondevel.py
             - balrog/production.py
     run-on-projects: ['mozilla-beta', 'mozilla-release', 'mozilla-esr45']
     toolchains:
         - win64-clang-cl
         - win64-rust
         - win64-sccache
@@ -357,16 +369,17 @@ win64-noopt/debug:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/noopt_debug.py
     run-on-projects: ['trunk', 'try']
     toolchains:
         - win64-clang-cl
         - win64-rust
         - win64-sccache
 
@@ -385,16 +398,17 @@ win32-noopt/debug:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win32.py
             - builds/taskcluster_sub_win32/noopt_debug.py
     run-on-projects: ['trunk', 'try']
     toolchains:
         - win32-clang-cl
         - win32-rust
         - win64-sccache
 
@@ -413,16 +427,17 @@ win32-rusttests/opt:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win32.py
             - builds/taskcluster_sub_win32/rusttests_opt.py
     run-on-projects: ['trunk', 'try']
     toolchains:
         - win32-clang-cl
         - win32-rust
         - win64-sccache
 
@@ -441,16 +456,17 @@ win64-rusttests/opt:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/rusttests_opt.py
     run-on-projects: ['trunk', 'try']
     toolchains:
         - win64-clang-cl
         - win64-rust
         - win64-sccache
 
@@ -469,16 +485,17 @@ win64-ccov/debug:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/ccov_debug.py
     run-on-projects: []
     toolchains:
         - win64-clang-cl
         - win64-rust
         - win64-sccache
 
@@ -498,16 +515,17 @@ win64-asan/debug:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
             PERFHERDER_EXTRA_OPTIONS: "debug asan"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/asan_debug.py
     run-on-projects: []
     toolchains:
         - win64-clang-cl
         - win64-rust
         - win64-sccache
 
@@ -527,16 +545,17 @@ win64-asan/opt:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
             PERFHERDER_EXTRA_OPTIONS: "opt asan"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/asan_opt.py
     run-on-projects: []
     toolchains:
         - win64-clang-cl
         - win64-rust
         - win64-sccache
 
@@ -558,16 +577,17 @@ win32-devedition-nightly/opt:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/releng.manifest"
     run:
         using: mozharness
         script: mozharness/scripts/fx_desktop_build.py
         options: [enable-pgo, append-env-variables-from-configs]
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win32.py
             - builds/taskcluster_sub_win32/opt.py
             - disable_signing.py
             - taskcluster_nightly.py
         custom-build-variant-cfg: devedition
     run-on-projects: ['mozilla-beta']
     toolchains:
         - win32-clang-cl
@@ -592,16 +612,17 @@ win64-devedition-nightly/opt:
         env:
             TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
     run:
         using: mozharness
         options: [append-env-variables-from-configs]
         script: mozharness/scripts/fx_desktop_build.py
         config:
             - builds/releng_base_firefox.py
+            - builds/taskcluster_base_windows.py
             - builds/taskcluster_base_win64.py
             - builds/taskcluster_sub_win64/opt.py
             - disable_signing.py
             - taskcluster_nightly.py
         custom-build-variant-cfg: devedition
     run-on-projects: ['mozilla-beta']
     toolchains:
         - win64-clang-cl

--- a/taskcluster/ci/static-analysis/kind.yml
+++ b/taskcluster/ci/static-analysis/kind.yml
@@ -91,16 +91,17 @@ jobs:
             env:
                 TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/releng.manifest"
         run:
             using: mozharness
             options: [append-env-variables-from-configs]
             script: mozharness/scripts/fx_desktop_build.py
             config:
                 - builds/releng_base_firefox.py
+                - builds/taskcluster_base_windows.py
                 - builds/taskcluster_base_win32.py
                 - builds/taskcluster_sub_win32/clang_debug.py
         toolchains:
             - win32-clang-cl
             - win32-rust
             - win64-sccache
 
     win32-st-an/opt:
@@ -118,16 +119,17 @@ jobs:
             env:
                 TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win32/releng.manifest"
         run:
             using: mozharness
             options: [append-env-variables-from-configs]
             script: mozharness/scripts/fx_desktop_build.py
             config:
                 - builds/releng_base_firefox.py
+                - builds/taskcluster_base_windows.py
                 - builds/taskcluster_base_win32.py
                 - builds/taskcluster_sub_win32/clang.py
         toolchains:
             - win32-clang-cl
             - win32-rust
             - win64-sccache
 
     win64-st-an/debug:
@@ -145,16 +147,17 @@ jobs:
             env:
                 TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
         run:
             using: mozharness
             options: [append-env-variables-from-configs]
             script: mozharness/scripts/fx_desktop_build.py
             config:
                 - builds/releng_base_firefox.py
+                - builds/taskcluster_base_windows.py
                 - builds/taskcluster_base_win64.py
                 - builds/taskcluster_sub_win64/clang_debug.py
         toolchains:
             - win64-clang-cl
             - win64-rust
             - win64-sccache
 
     win64-st-an/opt:
@@ -172,14 +175,15 @@ jobs:
             env:
                 TOOLTOOL_MANIFEST: "browser/config/tooltool-manifests/win64/releng.manifest"
         run:
             using: mozharness
             options: [append-env-variables-from-configs]
             script: mozharness/scripts/fx_desktop_build.py
             config:
                 - builds/releng_base_firefox.py
+                - builds/taskcluster_base_windows.py
                 - builds/taskcluster_base_win64.py
                 - builds/taskcluster_sub_win64/clang.py
         toolchains:
             - win64-clang-cl
             - win64-rust
             - win64-sccache

--- a/testing/mozharness/configs/builds/taskcluster_base_win32.py
+++ b/testing/mozharness/configs/builds/taskcluster_base_win32.py
@@ -1,49 +1,17 @@
 import os
-import sys
 
 config = {
-    'default_actions': [
-        'clone-tools',
-        'build',
-        'check-test',
-    ],
-    'app_ini_path': '%(obj_dir)s/dist/bin/application.ini',
-    # decides whether we want to use moz_sign_cmd in env
-    'enable_signing': True,
-    'vcs_share_base': os.path.join('y:', os.sep, 'hg-shared'),
-    'tooltool_script': [
-      sys.executable,
-      os.path.join(os.environ['MOZILLABUILD'], 'tooltool.py')
-    ],
-    'tooltool_bootstrap': 'setup.sh',
-    'enable_count_ctors': False,
-    'max_build_output_timeout': 60 * 80,
-
-    ###### 32 bit specific ######
     'base_name': 'WINNT_5.2_%(branch)s',
     'platform': 'win32',
-    'publish_nightly_en_US_routes': True,
     'env': {
         'BINSCOPE': os.path.join(
             os.environ['ProgramFiles(x86)'], 'Microsoft', 'SDL BinScope', 'BinScope.exe'
         ),
-        'HG_SHARE_BASE_DIR': os.path.join('y:', os.sep, 'hg-shared'),
-        'MOZBUILD_STATE_PATH': os.path.join(os.getcwd(), '.mozbuild'),
-        'MOZ_CRASHREPORTER_NO_REPORT': '1',
-        'MOZ_OBJDIR': '%(abs_obj_dir)s',
         'PDBSTR_PATH': 'C:/Program Files (x86)/Windows Kits/10/Debuggers/x86/srcsrv/pdbstr.exe',
-        'TINDERBOX_OUTPUT': '1',
-        'TOOLTOOL_CACHE': 'c:/builds/tooltool_cache',
-        'TOOLTOOL_HOME': '/c/builds',
-        'MSYSTEM': 'MINGW32',
-    },
-    'upload_env': {
-        'UPLOAD_HOST': 'localhost',
-        'UPLOAD_PATH': os.path.join(os.getcwd(), 'public', 'build'),
     },
     "check_test_env": {
         'MINIDUMP_STACKWALK': '%(abs_tools_dir)s\\breakpad\\win32\\minidump_stackwalk.exe',
         'MINIDUMP_SAVE_PATH': os.path.join(os.getcwd(), 'public', 'build'),
     },
     'mozconfig_platform': 'win32',
 }

--- a/testing/mozharness/configs/builds/taskcluster_base_win64.py
+++ b/testing/mozharness/configs/builds/taskcluster_base_win64.py
@@ -1,46 +1,14 @@
 import os
-import sys
 
 config = {
-    'default_actions': [
-        'clone-tools',
-        'build',
-        'check-test',
-    ],
-    'app_ini_path': '%(obj_dir)s/dist/bin/application.ini',
-    # decides whether we want to use moz_sign_cmd in env
-    'enable_signing': True,
-    'vcs_share_base': os.path.join('y:', os.sep, 'hg-shared'),
-    'tooltool_script': [
-      sys.executable,
-      os.path.join(os.environ['MOZILLABUILD'], 'tooltool.py')
-    ],
-    'tooltool_bootstrap': 'setup.sh',
-    'enable_count_ctors': False,
-    'max_build_output_timeout': 60 * 80,
-
-
-    ###### 64 bit specific ######
     'base_name': 'WINNT_6.1_x86-64_%(branch)s',
     'platform': 'win64',
-    'publish_nightly_en_US_routes': True,
     'env': {
-        'HG_SHARE_BASE_DIR': os.path.join('y:', os.sep, 'hg-shared'),
-        'MOZ_CRASHREPORTER_NO_REPORT': '1',
-        'MOZ_OBJDIR': '%(abs_obj_dir)s',
         'PDBSTR_PATH': 'C:/Program Files (x86)/Windows Kits/10/Debuggers/x64/srcsrv/pdbstr.exe',
-        'TINDERBOX_OUTPUT': '1',
-        'TOOLTOOL_CACHE': 'c:/builds/tooltool_cache',
-        'TOOLTOOL_HOME': '/c/builds',
-        'MSYSTEM': 'MINGW32',
-    },
-    'upload_env': {
-        'UPLOAD_HOST': 'localhost',
-        'UPLOAD_PATH': os.path.join(os.getcwd(), 'public', 'build'),
     },
     "check_test_env": {
         'MINIDUMP_STACKWALK': '%(abs_tools_dir)s\\breakpad\\win64\\minidump_stackwalk.exe',
         'MINIDUMP_SAVE_PATH': os.path.join(os.getcwd(), 'public', 'build'),
     },
     'mozconfig_platform': 'win64',
 }

new file mode 100644
--- /dev/null
+++ b/testing/mozharness/configs/builds/taskcluster_base_windows.py
@@ -0,0 +1,37 @@
+import os
+import sys
+
+config = {
+    'default_actions': [
+        'clone-tools',
+        'build',
+        'check-test',
+    ],
+    'app_ini_path': '%(obj_dir)s/dist/bin/application.ini',
+    # decides whether we want to use moz_sign_cmd in env
+    'enable_signing': True,
+    'vcs_share_base': os.path.join('y:', os.sep, 'hg-shared'),
+    'tooltool_script': [
+        sys.executable,
+        os.path.join(os.environ['MOZILLABUILD'], 'tooltool.py')
+    ],
+    'tooltool_bootstrap': 'setup.sh',
+    'enable_count_ctors': False,
+    'max_build_output_timeout': 60 * 80,
+
+    'publish_nightly_en_US_routes': True,
+    'env': {
+        'HG_SHARE_BASE_DIR': os.path.join('y:', os.sep, 'hg-shared'),
+        'MOZBUILD_STATE_PATH': os.path.join(os.getcwd(), '.mozbuild'),
+        'MOZ_CRASHREPORTER_NO_REPORT': '1',
+        'MOZ_OBJDIR': '%(abs_obj_dir)s',
+        'TINDERBOX_OUTPUT': '1',
+        'TOOLTOOL_CACHE': 'c:/builds/tooltool_cache',
+        'TOOLTOOL_HOME': '/c/builds',
+        'MSYSTEM': 'MINGW32',
+    },
+    'upload_env': {
+        'UPLOAD_HOST': 'localhost',
+        'UPLOAD_PATH': os.path.join(os.getcwd(), 'public', 'build'),
+    },
+}