We had a low stack wall installed as part of our front walk and the contractor used the cheapest cement available . That along with a bad New eng winter has caused the top layer of stone to loosen and we are not sure if this is just a simple cement patch or do we need to do something more to insure the wall does not keep falling apart. Advise is appreciated. Thanx

Here is a link that might be useful: Stone Wall, Front Walkway