diff --git a/packages/layout-engine/painters/dom/src/table/border-utils.test.ts b/packages/layout-engine/painters/dom/src/table/border-utils.test.ts
index ebadd10b2d..da9cdca1a8 100644
--- a/packages/layout-engine/painters/dom/src/table/border-utils.test.ts
+++ b/packages/layout-engine/painters/dom/src/table/border-utils.test.ts
@@ -39,10 +39,19 @@ describe('applyBorder', () => {
     expect(element.style.borderTop).toMatch(/2px solid (#FF0000|rgb\(255,\s*0,\s*0\))/i);
   });
 
-  it('should apply border with double style', () => {
+  // SD-3308: CSS `double` only renders two distinct rules at >= 3px (1px rule + 1px gap +
+  // 1px rule); below that it collapses to a single solid-looking line, while Word always
+  // shows two rules for w:val="double". The painter clamps the width up, never down.
+  it('clamps a double border below 3px up so both rules render', () => {
     const border: BorderSpec = { style: 'double', width: 2, color: '#FF0000' };
     applyBorder(element, 'Top', border);
-    expect(element.style.borderTop).toMatch(/2px double (#FF0000|rgb\(255,\s*0,\s*0\))/i);
+    expect(element.style.borderTop).toMatch(/3px double (#FF0000|rgb\(255,\s*0,\s*0\))/i);
+  });
+
+  it('keeps an authored double width that is already >= 3px', () => {
+    const border: BorderSpec = { style: 'double', width: 4, color: '#FF0000' };
+    applyBorder(element, 'Top', border);
+    expect(element.style.borderTop).toMatch(/4px double (#FF0000|rgb\(255,\s*0,\s*0\))/i);
   });
 
   it('should apply border with dashed style', () => {
diff --git a/packages/layout-engine/painters/dom/src/table/border-utils.ts b/packages/layout-engine/painters/dom/src/table/border-utils.ts
index 1285d0aae0..ccf9803796 100644
--- a/packages/layout-engine/painters/dom/src/table/border-utils.ts
+++ b/packages/layout-engine/painters/dom/src/table/border-utils.ts
@@ -83,7 +83,11 @@ export const applyBorder = (
   const width = border.width ?? 1;
   const color = border.color ?? '#000000';
   const safeColor = isValidHexColor(color) ? color : '#000000';
-  const actualWidth = border.style === 'thick' ? Math.max(width * 2, 3) : width;
+  // CSS `double` only renders two distinct rules at >= 3px (1px rule + 1px gap + 1px rule);
+  // below that it collapses to a single solid-looking line. Word always shows two rules for
+  // w:val="double", so clamp the rendered width up (never shrink an authored width). (SD-3308)
+  const minStyleWidth = style === 'double' ? 3 : 0;
+  const actualWidth = border.style === 'thick' ? Math.max(width * 2, 3) : Math.max(width, minStyleWidth);
   element.style[`border${side}`] = `${actualWidth}px ${style} ${safeColor}`;
 };