Building inspectors are the first line of defense for homebuyers when contractors unwittingly don't comply with building codes. Due to the increasing use of metal studs, inspectors and contractors need to be made aware of a little-known nasty problem.
Replacing wood with metal studs permits much worse "thermal bridging" through exterior walls with two serious results: The effectiveness of the wall insulation is reduced by roughly half, i.e. an R-19 batt becomes in effect only R-10 or 11, an R-11 batt only R-5 or 6. This will, of course, increase fuel bills.The thermal bridging will also cause any light-colored wall to develop "zebra-stripes" over time, often in only a year or two. Because the inside wall surface is much colder over each stud than over the insulation-filled cavity, condensation and consequent surface soiling soon become visible as darker stripes on the wall.
If the contractor says these problems are solved, ask for proof or warranty.
Jerry Zenger
Salt Lake City