Tornados pose a serious threat in the midsection and southern parts of the nation, but many other regions are also at risk. Designers and builders can choose from a variety of features to help minimize losses from high winds and the impact of flying debris. Measures are available to fortify all typical construction types, including concrete, masonry, wood frame, and structural insulated panels. Features may include structural strapping and bracing, wall cladding; roof sheathing and coverings; fortified entry doors, garage doors, windows, and skylights; and soffit and overhang design. Safe rooms are also recommended In high-tornado-risk areas. These are small rooms made of impact-resistant construction such as highly reinforced concrete. Unvented attics can minimize pressure differentials that can destroy roofs and can reduce opportunities for wind-driven rain to enter the structure. This can be accomplished with closed-cell spray foam applied under roof decks or with structural insulated panels.