Brandon writes from West Des Moines, Iowa: "I am refinishing a finished attic in a house that was built in the early 1940s. The insulation I removed was "KIM SUL". Evidently, this was a product manufactured by Kimberly-Clark in the 1930s & 1940s. The ceiling rafters are 3 3/4" in depth. I have been to several home improvement stores and have deduced that the highest R-value I can achieve with rolled insulation is R-13. Living in central Iowa, this doesn't provide for an optimal thermal barrier. I can place thicker insulation behind the knee walls and along the upper, flat portion of the ceiling. However the area between the top of the knee wall and the flat part of the ceiling (the angled portion) provides only a 3 3/4" depth. Are any alternative types of insulation available? Any ideas on how to insulate the angled portion of the ceiling?"

Answer: The only thing I can think of to suggest is building out the current construction to provide more space for insulation. For example, if you build out the current framing with 2x6's you would have enough space to accommodate an R-30 insulation.