diff --git a/src/core/geometry.ts b/src/core/geometry.ts
index cfa905b..6413581 100644
--- a/src/core/geometry.ts
+++ b/src/core/geometry.ts
@@ -33,6 +33,8 @@ export const DIM = {
   padThickness: 0.05,
   padSize: 1.0,
   blockSize: 1.2,
+  /** W11 (제안 2026-11-10): 받침블럭 콘크리트(패드 제외) 최소 높이 = 피복 50 + D13 = 63 mm (교대 I01과 같은 기준). */
+  blockMinHeight: 0.063,
   footingL: 10.4,
   footingW: 8.15,
   footingH: 2.0,
diff --git a/src/core/validate.ts b/src/core/validate.ts
index 8026b06..726e822 100644
--- a/src/core/validate.ts
+++ b/src/core/validate.ts
@@ -85,6 +85,13 @@ export function validatePier(input: PierInput, model: PierModel, issues: Issue[]
   if (minBlock <= 0) {
     issues.push({ code: 'W02', level: 'W', pier: input.name, message: '받침블럭 콘크리트 높이가 0 이하입니다. 블럭을 생략합니다.' });
   }
+  // W11 (2026-11-10): every block between 0 and the minimum height, from its own 교좌면 EL and z.
+  for (const b of model.blocks) {
+    const h = b.top - b.bottom;
+    if (h > 0 && h < DIM.blockMinHeight - 1e-9) {
+      issues.push({ code: 'W11', level: 'W', pier: input.name, message: `${b.row} 받침 ${b.no}번 받침블럭 콘크리트 ${Math.round(h * 1000)} mm가 최소 ${DIM.blockMinHeight * 1000} mm보다 낮습니다. 교좌면 EL과 받침 z를 확인하세요.` });
+    }
+  }
   // W03: bearing centre closer than half a block width to a step boundary (interior boundaries only).
   const halfBlock = DIM.blockSize / 2;
   for (const b of model.bearings) {
diff --git a/tests/seat-el.test.ts b/tests/seat-el.test.ts
index ffc466c..39709bd 100644
--- a/tests/seat-el.test.ts
+++ b/tests/seat-el.test.ts
@@ -73,4 +73,19 @@ describe('교좌면 EL 입력 (2026-11-03)', () => {
     validatePier(input, m, issues);
     expect(issues.filter((i) => i.code === 'W10').map((i) => i.level)).toEqual(['I']);
   });
+
+  it('W11 when a block is thinner than 63 mm (피복 50 + D13), from its own 교좌면 EL; none for P1', () => {
+    const p1 = withSeat(loadP1(), SEAT);
+    const ok: Issue[] = [];
+    validatePier(p1, buildPier(p1, P1CTX), ok);
+    expect(ok.filter((i) => i.code === 'W11')).toEqual([]);
+    // Bearing 1: z 43.561 − pad 50 − 50 mm block → 교좌면 43.461.
+    const thin = withSeat(loadP1(), [43.461, ...SEAT.slice(1)]);
+    const m = buildPier(thin, P1CTX);
+    const issues: Issue[] = [];
+    validatePier(thin, m, issues);
+    const w = issues.filter((i) => i.code === 'W11');
+    expect(w.length).toBe(1);
+    expect(w[0].message).toContain('받침 1번');
+  });
 });