Is there such a thing as residual alcohol build up?

No: Alcohol is metabolized and excreted pretty quickly (watch the lavatory at a bar or saloon; pretty busy place). Chronic alcoholics wouldn't keep needing to drink alcohol built-up. Obviously there are secondary effects from long-term alcohol on the body (cirrhosis and other earlier liver disease; neuropathy, mental confusion for instance); but if you mean does alcohol itself build up, no.

No: Alcohol is generally metabolized at the rate of one ounce per hour. Once all the alcohol is metabolized, it is gone from the body. It does not build up. One can, however, have residual effects from alcohol, especially with heavy drinking. Alcohol can adversely affect every organ in the body, except, interestingly, the kidneys.