diff --git a/compilerplugins/clang/bufferadd.cxx b/compilerplugins/clang/bufferadd.cxx
index 5327384c4ec3..9d49f7fdc40b 100644
--- a/compilerplugins/clang/bufferadd.cxx
+++ b/compilerplugins/clang/bufferadd.cxx
@@ -83,6 +83,7 @@ public:
 
     bool VisitStmt(Stmt const*);
     bool VisitCallExpr(CallExpr const*);
+    bool VisitCXXMemberCallExpr(CXXMemberCallExpr const*);
     bool VisitCXXConstructExpr(CXXConstructExpr const*);
     bool VisitUnaryOperator(UnaryOperator const*);
 
@@ -143,6 +144,35 @@ bool BufferAdd::VisitCallExpr(CallExpr const* callExpr)
     return true;
 }
 
+bool BufferAdd::VisitCXXMemberCallExpr(CXXMemberCallExpr const* expr)
+{
+    if (ignoreLocation(expr))
+    {
+        return true;
+    }
+    auto const e = dyn_cast<DeclRefExpr>(expr->getImplicitObjectArgument()->IgnoreParenImpCasts());
+    if (e == nullptr)
+    {
+        return true;
+    }
+    auto const d = dyn_cast<VarDecl>(e->getDecl());
+    if (d == nullptr)
+    {
+        return true;
+    }
+    auto const tc = loplugin::TypeCheck(d->getType());
+    if (!(tc.Class("OStringBuffer").Namespace("rtl").GlobalNamespace()
+          || tc.Class("OUStringBuffer").Namespace("rtl").GlobalNamespace()))
+    {
+        return true;
+    }
+    if (!isMethodOkToMerge(expr))
+    {
+        badMap.insert(d);
+    }
+    return true;
+}
+
 bool BufferAdd::VisitCXXConstructExpr(CXXConstructExpr const* callExpr)
 {
     if (ignoreLocation(callExpr))
diff --git a/compilerplugins/clang/test/bufferadd.cxx b/compilerplugins/clang/test/bufferadd.cxx
index 464214461083..b7712b31f464 100644
--- a/compilerplugins/clang/test/bufferadd.cxx
+++ b/compilerplugins/clang/test/bufferadd.cxx
@@ -117,6 +117,16 @@ void f7()
     OStringBuffer noelf7("xxx");
     noelf7 = "xxx" + noelf7 + "xxx";
 }
+char16_t rnd();
+void f8(sal_Int32 n)
+{
+    OUStringBuffer buf;
+    auto p = buf.appendUninitialized(n);
+    for (sal_Int32 i = 0; i != n; ++i)
+    {
+        *p++ = rnd();
+    }
+}
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */