How do I stop water damage to the foundation, siding, and sills?

Updated

1998
Layton Farm-Layton, UT after rehabilitation.

Answer:

Water damage is most often caused by improper drainage away from buildings. Where located next to unavoidable slopes, water must be redirected around a building. This can be done with the help of concrete gutters or with a linear French drain. The proper grade away from any structure is at least 3-5%. (Example: a 5% grade is a 6 inch drop in the first 10 feet)

A problem for barns built on relatively level ground may be the proximity of the ground to the sills and siding. It is recommended that at least 10 inches of foundation be exposed, any less will not allow for an adequate drying area for the sills or siding.

For more information about moisture abatement, read the National Park Service's Preservation Brief #39.