The author concludes that within ten years, most new homes made in North America will have steel frameworks instead of wood ones. This is because the sizes of lumber most commonly used in home construction are getting worse in quality and are getting more expensive. In addition, steel has an advantage over wood in that steel will not warp, rot or split.

The author assumes that the steel required for houses is not getting worse in quality. The author also assumes that there aren’t other disadvantages about steel compared to wood that might outweigh the disadvantages brought up about wood.