diff --git a/src/mem/superslab.h b/src/mem/superslab.h
index 50e6e16..93aabb9 100644
--- a/src/mem/superslab.h
+++ b/src/mem/superslab.h
@@ -81,7 +81,10 @@ namespace snmalloc
     {
       allocator = alloc;
 
-      if (kind != Super)
+      // If Superslab is larger than a page, then we cannot guarantee it still
+      // has a valid layout as the subsequent pages could have been freed and
+      // zeroed, hence only skip initialisation if smaller.
+      if (kind != Super || (sizeof(Superslab) >= OS_PAGE_SIZE))
       {
         if (kind != Fresh)
         {