What type of roof material should I use?

Updated

2003
Harmony Hill Farm-Colo, IA after rehabilitation.

Answer:

Wood shakes or shingles are the most historically accurate roofing material for many barns. However, they can be relatively expensive compared with other choices.

Asphalt shingles are less expensive than wood shingles but may not be as durable or may violate the historical integrity of the barn. Asphalt shingles should be installed on decking or may be installed over one previous layer of shingles if the decking is still intact.

While modern metal roofing is not the most historically accurate material for old barns, it is less expensive than wood shingles and longer lasting than asphalt.

More information can be found in Barn Aid #4: Barn Roofs, and by reading the National Park Service's Preservation Brief #4.