diff --git a/course/format/social/format.php b/course/format/social/format.php
index 0a2398601d7..7cf3f2b84b7 100644
--- a/course/format/social/format.php
+++ b/course/format/social/format.php
@@ -21,7 +21,7 @@
     $strgroupmy = get_string('groupmy');
     $editing    = $PAGE->user_is_editing();
 
-    echo '<table id="layout-table">';
+    echo '<table id="layout-table" cellspacing="0">';
     echo '<tr>';
 
     if (blocks_have_content($pageblocks, BLOCK_POS_LEFT) || $editing) {
diff --git a/course/format/topics/format.php b/course/format/topics/format.php
index ece13953549..5755cac1788 100644
--- a/course/format/topics/format.php
+++ b/course/format/topics/format.php
@@ -59,7 +59,7 @@
 
 
 /// Layout the whole page as three big columns.
-    echo '<table id="layout-table"><tr>';
+    echo '<table id="layout-table" cellspacing="0"><tr>';
 
 /// The left column ...
 
diff --git a/course/format/weeks/format.php b/course/format/weeks/format.php
index 1cca2cef8b1..7f1e9adbe43 100644
--- a/course/format/weeks/format.php
+++ b/course/format/weeks/format.php
@@ -50,7 +50,7 @@
 
 
 /// Layout the whole page as three big columns.
-    echo '<table id="layout-table"><tr>';
+    echo '<table id="layout-table" cellspacing="0"><tr>';
 
 /// The left column ...