diff --git a/.github/workflows/cmake.yml b/.github/workflows/cmake.yml
index ed3a79b..5113952 100644
--- a/.github/workflows/cmake.yml
+++ b/.github/workflows/cmake.yml
@@ -12,11 +12,12 @@
             os: ubuntu-latest
             compiler: gcc
 
-          - name: Ubuntu GCC ISB
+          # Test out of source builds
+          - name: Ubuntu GCC OSB
             os: ubuntu-latest
             compiler: gcc
-            build-dir: "."
-            src-dir: "."
+            build-dir: ../build
+            src-dir: ../zlib
 
           - name: Ubuntu Clang
             os: ubuntu-latest
@@ -50,13 +51,13 @@
       uses: actions/checkout@v3
 
     - name: Generate project files
-      run: cmake -S ${{ matrix.src-dir || '../zlib' }} -B ${{ matrix.build-dir || '../build' }} ${{ matrix.cmake-args }} -D CMAKE_BUILD_TYPE=${{ matrix.build-config || 'Release' }}
+      run: cmake -S ${{ matrix.src-dir || '.' }} -B ${{ matrix.build-dir || '.' }} ${{ matrix.cmake-args }} -D CMAKE_BUILD_TYPE=${{ matrix.build-config || 'Release' }}
       env:
         CC: ${{ matrix.compiler }}
 
     - name: Compile source code
-      run: cmake --build ${{ matrix.build-dir || '../build' }} --config ${{ matrix.build-config || 'Release' }}
+      run: cmake --build ${{ matrix.build-dir || '.' }} --config ${{ matrix.build-config || 'Release' }}
 
     - name: Run test cases
       run: ctest -C Release --output-on-failure --max-width 120
-      working-directory: ${{ matrix.build-dir || '../build' }}
+      working-directory: ${{ matrix.build-dir || '.' }}
diff --git a/.github/workflows/configure.yml b/.github/workflows/configure.yml
index 2c19e60..09f67b4 100644
--- a/.github/workflows/configure.yml
+++ b/.github/workflows/configure.yml
@@ -13,12 +13,13 @@
             compiler: gcc
             configure-args: --warn
 
-          - name: Ubuntu GCC ISB
+          # Test out of source builds
+          - name: Ubuntu GCC OSB
             os: ubuntu-latest
             compiler: gcc
             configure-args: --warn
-            build-dir: "."
-            src-dir: "."
+            build-dir: ../build
+            src-dir: ../zlib
 
           - name: macOS GCC
             os: macos-latest
@@ -31,9 +32,9 @@
 
     - name: Generate project files
       run: |
-        [ -d ${{ matrix.build-dir || '../build' }} ] || mkdir ${{ matrix.build-dir || '../build' }}
-        cd ${{ matrix.build-dir || '../build' }}
-        ${{ matrix.src-dir || '../zlib' }}/configure ${{ matrix.configure-args }}
+        [ -d ${{ matrix.build-dir || '.' }} ] || mkdir ${{ matrix.build-dir || '.' }}
+        cd ${{ matrix.build-dir || '.' }}
+        ${{ matrix.src-dir || '.' }}/configure ${{ matrix.configure-args }}
       env:
         CC: ${{ matrix.compiler }}