I have a 3 yr. old home where the master bath was built over the 2 car garage. In winter, should 2nd level zone be set for 68 degrees, the MB is about 54 or less degrees. Pipes were repeatedly freezing and have finally burst even though we have used a heater to keep MB warm enough and rigid board was installed over back wall through a crawl space behind the shower/toilet/jacuzzi. Pipes had burst in garage...and I'm trying to determine if garage was properly insulated. Soffit runs the length of back wall (which now has to be repaired due to water damage. There is no insulation in the back wall of the garage and the ceiling had about 3-3.5 inches of insulation in a depth of 9 inches(bottom of floor to finished drywall). We live in Londonderry NH, so it's quite windy and cold. Plumber initially stated that there was no insulation around the pipes and he felt that the pipes could have benefited with blown insulation. He told the Home owner's claim rep. that the insulation was adequate..go figure. So there are 2 issues, was the builder in compliance, and what should I do to best prevent future freezes...should I use rigid board over the ceiling of the garage? should the back wall of the garage be insulated? Heat tape? Help...I know nothing about this!!