Need correction : A Wall and My Friendship

I have a small home and have been living here since I graduated from my university. Next to my house is a neighbor. I generally always greeted him with a little smile early in the morning. But one day, he built a wall and fence between our houses. Now I can't greet him anymore because the wall has separated our homes, but hopefully not our friendship. I think, the wall is just preventing me from greeting him.