diff --git a/packages/core/src/Helm.ts b/packages/core/src/Helm.ts
index 5ce0e2c..11a1a71 100644
--- a/packages/core/src/Helm.ts
+++ b/packages/core/src/Helm.ts
@@ -71,7 +71,7 @@ export class Helm {
             let tmpValuesDir = '';
             if (args.valuesObject) {
                 try {
-                    const content = yaml.stringify(args.valuesObject);
+                    const content = yaml.stringify(args.valuesObject, { schema: 'yaml-1.1' });
                     tmpValuesDir = fs.mkdtempSync(path.join(os.tmpdir(), 'k8skonf-helm-values-'), {
                         encoding: 'utf-8',
                     });
diff --git a/packages/core/src/K8sApp.ts b/packages/core/src/K8sApp.ts
index 9df3dab..5954a78 100644
--- a/packages/core/src/K8sApp.ts
+++ b/packages/core/src/K8sApp.ts
@@ -24,7 +24,7 @@ export class K8sApp {
     }
 
     toYaml() {
-        return `---\n${this.resources.map((resource) => yaml.stringify(resource)).join('---\n')}`;
+        return `---\n${this.resources.map((resource) => yaml.stringify(resource, { schema: 'yaml-1.1' })).join('---\n')}`;
     }
 
     save() {
@@ -41,7 +41,7 @@ export class K8sApp {
                 );
                 fs.writeFileSync(
                     path.join(this.outputName, `${r.kind}.${r.metadata.name}.yaml`),
-                    yaml.stringify(r),
+                    yaml.stringify(r, { schema: 'yaml-1.1' }),
                 );
             }
         } else {