Suggestions on heating detached garage - running gas? Furnace type?

if the line is still intact a pro MAY be able to run a new plastic line thru the existing old one saving a ton of excevating. replacement service lines are nearly always done this way locally.

metal detector wouldnt work at 3 feet

That depth wasn't a code requirement, but the distance between the gas line and electrical line was important, and it is easier to make one trench at 3' than two at 2'.

JK

Heat... to what temp? For what purpose? Is it electracitified? -----

- gpsman

Through maybe a 3/4" gas pipe?

Small service lines are likely run just like cables, with a mole or cable plow.

JK

I just realized that no one really answered your original question.

Depending on where you are, you might be able to run soft copper for gas line, but it seems that most underground gas piping in my area is done in polyethylene tubing (or pipe). I'm not sure that you can buy it from anywhere but a heating supply house, who probably wouldn't sell it to you. I supposed you could run CSST through maybe 2" PVC, since it isn't suitable for direct burial. What was the old line made of?

JK

The old line looks like a steel type typical pipe. The garage was from 1942. Not sure if the gas line was that old. My guess it was added in the early 70's