I have had an on again/off again relationship with This Old House since its earliest days. I think its recent project of rebuilding a house for a couple with a handicapped child is one of the bigger money pits for the sake of just spending money I have seen. Anyway it looks like all the interior wall lumber is 2x6 engineered. I get 2x6 for exteriors and for chases but everywhere? Are engineered 2x becoming common? Cost effective?