I think you'll need to provide more details.
What do you have now? A point cloud? A surface?
What software are you using, and/or familiar with?
How good is the scan data? Holes? Roughness?
Pictures help everyone get an idea of what is involved.
Thickening a surface is not very difficult, but if the geometry is very complex you can end up with surfaces passing through each other.
Post the data, or a similar model and people can take a look at it to figure out a good process instead of guessing.