diff --git a/src/core/parseWorkbook.ts b/src/core/parseWorkbook.ts
index 38d3b1f..e2fc47b 100644
--- a/src/core/parseWorkbook.ts
+++ b/src/core/parseWorkbook.ts
@@ -78,9 +78,28 @@ function parseSheet(grid: Grid, sheet: string, issues: Issue[]): PierInput[] {
   }
 
   const piers: PierInput[] = [];
+  if (pierHeaders.length === 0 && (ipHeaders.length > 0 || bearingHeaders.length > 0)) {
+    issues.push({
+      code: 'E05',
+      level: 'E',
+      message: `${sheet}: 교각 정보 표가 이 시트에 없습니다. 교각 1기의 세 표(교각 정보·IP·받침)를 한 시트에 두세요 (시트 1장 = 교각 1기).`,
+    });
+  }
   for (const h of pierHeaders) {
     for (const { cells, index } of readBlock(grid, h)) {
       const name = String(cells[0]);
+      const pierIps = ips.filter((p) => p.pier === name);
+      const pierBearings = bearings.filter((b) => b.pier === name);
+      if (pierIps.length === 0 || pierBearings.length === 0) {
+        const missing = [pierIps.length === 0 ? 'IP' : null, pierBearings.length === 0 ? '받침' : null].filter(Boolean).join('·');
+        issues.push({
+          code: 'E05',
+          level: 'E',
+          pier: name,
+          message: `${index + 1}행: ${missing} 표가 이 시트에 없습니다. 교각 1기의 세 표를 한 시트에 두세요 (시트 1장 = 교각 1기).`,
+        });
+        continue;
+      }
       const bad = bearings.find((b) => b.pier === name && !b.azimuthOk);
       if (bad) {
         issues.push({
diff --git a/src/main.ts b/src/main.ts
index cb15382..6dc7fcc 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -454,6 +454,12 @@ function updateApply(): void {
 function loadBytes(bytes: Uint8Array, fileName: string): void {
   const { piers, sheets } = parseWorkbook(XLSX.read(bytes, { type: 'array' }));
   const entries = piers.map((input) => buildEntry(input, false));
+  // A sheet is selectable only if every pier in it builds. Show the reason next to the sheet.
+  for (const sheet of sheets) {
+    const own = entries.filter((e) => e.input.sheet === sheet.name);
+    for (const e of own) sheet.issues.push(...e.issues.filter((i) => i.level === 'E'));
+    sheet.ok = sheet.ok && own.every((e) => e.model !== null);
+  }
   const pending: Pending = { fileName, entries, sheets, preview: null };
   for (const e of entries) e.checked = selectable(pending, e);
   pending.preview = entries.find((e) => selectable(pending, e))?.input.name ?? entries[0]?.input.name ?? null;
diff --git a/tests/parse.test.ts b/tests/parse.test.ts
index dd08d1c..d7350fe 100644
--- a/tests/parse.test.ts
+++ b/tests/parse.test.ts
@@ -49,3 +49,14 @@ describe('sheet report (spec §2.3)', () => {
     expect(piers).toHaveLength(0);
   });
 });
+
+describe('tables split across sheets (spec §2.2: 시트 1장 = 교각 1기)', () => {
+  it('reports E05 and drops the pier when the IP table is not on the same sheet', () => {
+    const wb = loadWorkbook();
+    wb.Sheets['intent.PR']['B25'].v = '기타';
+    const { piers, sheets, issues } = parseWorkbook(wb);
+    expect(issues.map((i) => i.code)).toContain('E05');
+    expect(piers).toHaveLength(0);
+    expect(sheets[0].ok).toBe(false);
+  });
+});