Heating a garage is a waste of money and actually encourages your car to rust out in the winter.

I hade my master bath toilet and the cold water feed for the washer in the adjacent laundry room freeze up twice last year. The master bathroom bumps out 18" from the rest of the house. These pipes run up the outside wall and thru the subfloor of that 18" bumpout section. FOr whatever stupid reason, the builder's design didn't put the piping on an interior wall. The attempted fixes last year included adding more insulation inside the soffit of that bumpout, and then adding an second wall vent in the laundry room behind the washer so that warm air could circulate behind the wall, and that was supplemented by encasing the pipes behind there with insluated foam board of some kind.

Anyway,the same pipes froze again last night. BY the time my wife got the builder's site foreman over to the house, the pipes thawed out. Toilet bowl filled back up and the cold water runs again on the washer. How that happened overnight is beyond me. It had to be in the teens during the overnight, if not colder. Well, he first tried to blame the frozen pipe situation on the fact that he says we leave our garage door open for great periods of time. That’s crap, IM! How can that seriously be a contributing factor to the pipes in question?? My master bedroom is fully above the garage space (it's not abnormally cold and the proper insulation is in the garage ceiling, according to code), and adjacent is the master bath, and adjacent is the laundry room. The feed pipes for the toilet and washer are located about 14 feet to the side of the garage area on the backside of the house and in the area of the first floor ceiling/second floor subflooring. And he's claiming that cold air from the garage is causing or contributing to these pipes freezing? It's not like we leave the garage open for extended periods of time in freezing weather, and we certainly don't leave it open overnight! The master shower and jacuzzi tub don't freeze up, and they are phjysically closer to the garage than the toilet. GIVE ME A BREAK!!! In addition to that, I’d also point out the fact that the toilet area of the master bath is directly above the first floor pantry, which is extremely warm, with a floor vent in there and the pantry door closed most all the time. All that warm air in the ceiling of the pantry. What a real jerk this guy is, trying to peddle this lame excuse as the contributing factor to the pipes freezing!! Two different plumbing contractors that have worked for the home builder in the past year, they both said the piping didn't belong on the outside wall. But the foreman says they aren't going to tear up the tile flooring and walls to move the pipes. They want the issue to be shored up via insulating methods.

Any comments? The garage excuseby the foreman is bull$hit, right?

New builder, yep, 2.5yr old house.

We keep the heat at about 46-48. We still have an issue with the toilet supply freezing if the temp outside hits 0 or below. I've looked at the construction pics and determined it is because that pipe is too close to the outside wall and there is a dip in it. We have PEX, so it doesn't break when it freezes. We just run the hot water in one of the sinks and the toilet supply defrosts. We plan to take down a small section of the ceiling and fix the pipe there (get rid of the dip, move it in a little and insulate the area better).

Many people around here heat their garages. Even if the garage would stay 20 degrees above outside, that is too cold. I don't want my garage to go below freezing.

Do you know where your pipes run?
Heating the garage won't necessarily work. Let's say the issue is that the pipes are against the rim joist, insulating the walls won't help because too much cold air migrates in from there compared to the amount of heat that will.

How cold was it when the pipes froze? Insulating and finishing the garage is not cheap, neither is adding the heat source, that is why most garages only have the house-shared walls finished (required by fire code).