Being able to see light coming through siding may not be of any importance either. Many barns have been sided with green siding intentionally. When the siding boards shrink during drying, minor gaps appear along the edges that actually allow ventilation. Large areas of light, however, probably indicate something more. Larger openings (more than 1/4") can allow wind blown rain to enter and saturate timbers inside the barn. These openings need to be investigated. In some cases timbers may have moved due to damage at the joinery. In others, siding boards may become loose due to nails rusting or siding girts rotting. Often siding is "pushed" off the barn inadvertently while loading hay or moving equipment. These types of situations may or may not be within the scope of the owner, but need to be remedied expediently none the less.
Roofing failures are typically well beyond the capabilities or willingness of barn owners to undertake. In most cases this is a good situation. It is just as important, however, that the person chosen to do the work is well experienced and equipped. Again, the barn owner must be the sentry to prevent roof damage from causing expensive damage to the barn's structure. There are several types of roofing commonly found on barns. The oldest common roofing is wooden shakes, but in Ohio it is rare to see shakes on a barn except from the inside where they still show after being covered with a new roof that is usually metal. Shake roofs are nearly impossible to repair. If a barn still has a shake roof and it is leaking, it should be replaced immediately.
Metal roofs come in two forms in Ohio. The earliest, and still the highest quality metal roofs, are "standing seam" that are installed using concealed fasteners. These roofs can easily last 100 years, but do require repainting from time to time. The appearance of rust on a standing seam roof should not be ignored for any length of time. It will quickly penetrate the metal and weaken the roof, as well as shorten its life. When rust begins to show it's time to have the roof repainted with a paint designed specifically for that purpose. If the roof has been left rusting for years, it may have to be replaced. The other type of metal roof commonly found in Ohio is the exposed fastener or "ag panel" roof. These come in corrugated as well as ribbed patterns and are usually a lighter gauge than standing seam. Because they are thinner, and the fact that the exposed fasteners can fail, these types of roofs are more prone to blow off in high winds. Any loose or missing panels should be immediately taken care of, but first the wooden slats or skip sheathing should be inspected for damage or rot and repaired.
Slate roofs are the most beautiful barn roofs in our state. Often they are decorated with dates and names as well as images of farm animals. When slate roofs are installed the barn's steward has chosen the best roof money can buy, but unfortunately this doesn't always translate into a long lived roof. The reason for this is slate roofs require regular maintenance. Unlike manufactured metal or shingle roofs, slates are made from quarried stone that often has unseen defects. These defects include minor fractures that may cause a slate to fail and slide off the roof. This can also be caused by movement in the barn, and more often by an uneducated roofer walking on the slates. Every slate that gets stepped on will be broken. The barn owner should inspect the roof every spring to see if the snow has dragged off any broken slates. It is also important to inspect areas where valleys are formed by the addition of straw sheds. These are often metal that rusts out after 80-100 years. These problems can easily be repaired by a roofer with experience in such work.
Asphalt or composition shingle roofing is more typically found on houses than barns in Ohio. Shingles are not well suited to high wind areas like barn roofs. They are also quite heavy and require a solid wooden nailing surface, which most barns do not have. The weight of a shingle roof can also cause damage to a timber frame barn. Since the frame members were most likely sized for a much lighter roof such as metal or shakes, the added weight can cause premature failing. For these reasons we do not recommend putting composition shingles on barns. We would also recommend their removal, if they are at the end of their useful life, and replacement with a more suitable material. Unfortunately, they will most likely end up in a landfill since they are so difficult to recycle.