I had a frost proof faucet outside of the house that was leaking around the handle and not thru the spout. I pulled the stem out of the faucet and took it to a faucet store (really). They replaced the graphite string with a sillicone washer and the washer in the end. I brought it home and re-installed it. Now there is a very tiny leak coming out of the spout (I doubt it would leak a cup a month) but I am worried about it freezing this winter. I assume the problem is in the seat in the faucet.
Half of the water line that feeds the faucet is covered up by the basement ceiling including where the faucet leads to the basement, but is exposed for about 15 feet from the feeder line. I really don't want to tear out the ceilling to replace the faucet, but was wondering if it would be acceptable to install an in-line water valve and shut the water off for the winter. Later next spring, I would replace the outside faucet and could do it without shutting the water off for the whole house. Is this OK? Also there is about an inch between the stringer and copper pipe. Is this enough room to solder on a shutoff valve? I plan on wetting a towel and nailing it on the stringer to protect it from the torch.

Thanks

CJ