Vapor Barrier Video
Older homes had tar paper to prevent water from getting to the wood framing. Today, houses are built with air and water infiltration barriers. They won't let water in, but they will let water vapor out. These vapor barriers come on large rolls. Installation of the vapor barriers can be done with either special nails or staples.
The most important installation step is to tape over the seams. There is a special tape to seal the seams so water does not leak in behind the barrier.
Allow the barrier to extend about an inch down over the foundation. This will prevent any water from leaking in as it runs down off the siding. These new water infiltration barriers will protect your house.