What does the sand represent in the novel "The House of Sand and Fog"?
I think the fog represent the appearances and not the reality.
For instance Behrani works very hard in a hot and dirty enviroment. But before he comes home, he puts this appearance of himself and where he works that isn't true by wearing a suit.
Lester is a cop, and puts this appearance of himself that he follows the law, and is a strong mancho guy. But when he does a flashback, yuou can tell his weaknesses and his low self-esteem.
The imagery represented in the "Sand" in the title has to do with the instability of life. When something is built on a foundation of sand, like the situation in the story, with the ownership of the house, things can sink and shift very quickly.
Just like a castle built of sand on the beach, a strong and powerful wave can destroy a beautiful, sculpted masterpiece and draw the sand down into the ocean, so too do the lives of Kathy and the Behranis' get drowned with a giant wave of destruction.
The fog in the title, like real fog, masks what is just ahead. Like when you are driving in the fog, you can barely see just ahead of you on the road. The fog, shrouds the tragic events just ahead. Clearly, on a sunny day, the house and its occupants look like normal, happy people. But the fog of San Franciso, masks the truth of what really goes on in this house. The fog acts as a blanket to cover the murder and suicide that takes place.
Behrani washes himself because he is a proud and dignified man and does not want to associate himself with dirty labor, nor does he want his family to see him doing this kind of work. It is an issue of dignity based on his cultural tradition.
Lester, even though he is a policeman, he is not a moral man. He is married and cheats on his wife with Kathy. He tries to intimidate the Behrani family, contributing to the tragic circumstances of the book.