IBHS: Attached Structures often Magnify Damage

Structures attached to manufactured homes fail about 80 percent of the time during high wind conditions such as tornadoes and hurricanes, an analysis of closed insurance claim files from 2004’s Hurricane Charley concluded.

According to the Insurance Institute for Business & Home Safety, which conducted the study, failure of attached structures such as carports, awnings and porches can result in damage not only to host buildings but to nearby structures as well.

One reason that attachments to site-built or manufactured houses often fail is that they are typically designed to lower building standards than those of the homes to which they are attached.

If replacing a deficient carport is not in the picture, the IBHS suggests a few retrofits to upgrade the wind resistance of existing units:

• Replace any small, weak or damaged posts, and strengthen post connections to the foundation/carport slab using appropriate brackets, bolts and anchors;
• Supplement attachments of roof pans fastened with corroded fasteners, or fasteners without washers, by adding larger-size fasteners that use combination metal/neoprene washers — and installing fasteners no more than 4″ apart across each panel;
• Unless the home included specific anchorage designed to support the roof of the attached structure, install posts and a support beam near the side of the home and attach roof pans to this beam.