David writes from Lindsay, Ontario: "I am considering plaving a 1 1/2-Inch wide by 1/2-inch thick 200 rigid foam strips over interior wood studs prior to installing my drywall to improve both the sound and serve as a thermal break. What are your thoughts?"

Answer: Celfort® 200 extruded polystyrene foam boards are excellent for thermal break over wood studs. In order to offer the best thermal break, they should be installed on the exterior side of the studs, not from the inside.

However, in general, rigid foam boards do not provide good acoustical qualities due to their density. You will hear a little difference because of the air tightness of your home once the boards are installed, especially when the renovations include better windows and doors.

For interior walls, the acoustical principles are: absord sound and break the path of sound. To accomplish these objectives, add Quietzone® acoustical batts in the wall cavity and use resilient channels on one side of the interior wood studs prior to installing the drywall.

For exterior walls, use PINK Fiberglas®batt insulation which will provide both thermal and acoustical properties (R-12 or R-14 for 2x4 studs; and R-20, R-22 or R-24 for 2x6 studs).