There are basically three choices for walls

• Traditional stick frame -- Generally, contractors will only be familiar with stick frame as an enclosure option. In stick frame enclosures, the walls are built as if the timber frame were just another stud.The walls are built with studs between the posts or bents and the timber frame holds up the roof.
• Wrap and strap -- Many timber framers use a system called wrap and strap, usually done on site by the timber framing crew with rigid foam which uses less lumber and is more energy efficient than traditional stick framed walls.
• Panels -- More and more timber framers are recommending the use of enclosure panels to finish the enclosure. Panels are made in the factory by laminating rigid foam to oriented strand board (a new form of plywood) and other building materials to form a sandwich panel. Panels can provide substantial energy advantages compared to ordinary wood-framed walls.

-- Tips courtesy of HomeAdvisor.com