diff --git a/internal/build/lifecycle_execution.go b/internal/build/lifecycle_execution.go
index ccad060a34..89f4f477fa 100644
--- a/internal/build/lifecycle_execution.go
+++ b/internal/build/lifecycle_execution.go
@@ -813,7 +813,8 @@ func (l *LifecycleExecution) hasExtensions() bool {
 }
 
 func (l *LifecycleExecution) hasExtensionsForBuild() bool {
-	fis, err := os.ReadDir(filepath.Join(l.WorkingDir, "generated", "build"))
+	// the directory is <layers>/generated/build inside the build container, but `CopyOutTo` only copies the directory
+	fis, err := os.ReadDir(filepath.Join(l.WorkingDir, "build"))
 	if err != nil {
 		return false
 	}
diff --git a/internal/build/lifecycle_execution_test.go b/internal/build/lifecycle_execution_test.go
index d1b0c2688b..85fdcfb468 100644
--- a/internal/build/lifecycle_execution_test.go
+++ b/internal/build/lifecycle_execution_test.go
@@ -125,9 +125,10 @@ func testLifecycleExecution(t *testing.T, when spec.G, it spec.S) {
 			lifecycle.WorkingDir, err = os.MkdirTemp("", "pack.unit")
 			h.AssertNil(t, err)
 			if extensionsForBuild {
-				err = os.MkdirAll(filepath.Join(lifecycle.WorkingDir, "generated", "build"), 0755)
+				// the directory is <layers>/generated/build inside the build container, but `CopyOutTo` only copies the directory
+				err = os.MkdirAll(filepath.Join(lifecycle.WorkingDir, "build"), 0755)
 				h.AssertNil(t, err)
-				_, err = os.Create(filepath.Join(lifecycle.WorkingDir, "generated", "build", "some-dockerfile"))
+				_, err = os.Create(filepath.Join(lifecycle.WorkingDir, "build", "some-dockerfile"))
 				h.AssertNil(t, err)
 			}
 			if extensionsForRun {