diff --git a/HISTORY.rst b/HISTORY.rst
index f6c3274e..82e88c12 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -24,6 +24,9 @@ PlatformIO 3.0
   (`pull #949 <https://github.com/platformio/platformio-core/pull/949>`_)
 * Fixed linter error "unity.h does not exist" for Unit Testing
   (`issue #947 <https://github.com/platformio/platformio-core/issues/947>`_)
+* Fixed issue when `Library Dependency Finder (LDF) <http://docs.platformio.org/page/librarymanager/ldf.html>`__
+  does not handle custom ``src_dir``
+  (`issue #942 <https://github.com/platformio/platformio-core/issues/942>`_)
 
 -------
 
diff --git a/platformio/builder/tools/piolib.py b/platformio/builder/tools/piolib.py
index 1daedc6b..4798f24d 100644
--- a/platformio/builder/tools/piolib.py
+++ b/platformio/builder/tools/piolib.py
@@ -411,6 +411,10 @@ class ProjectAsLibBuilder(LibBuilderBase):
         LibBuilderBase.__init__(self, *args, **kwargs)
         self._is_built = True
 
+    @property
+    def src_dir(self):
+        return self.env.subst("$PROJECTSRC_DIR")
+
     @property
     def lib_ldf_mode(self):
         mode = LibBuilderBase.lib_ldf_mode.fget(self)