Walls – How to adjust vent location in siding

The purpose of the extension on a frost free faucet is to get the valve itself in a heated space inside of your home so that it could never freeze (see the below diagram). If you only have an inch or so of insulation that's being penetrated by these plumbing pipes, it's likely that the valve would still reach the freezing point inside of your wall. So any type of build out on the outside of your home to mount the faucet is defeating the purpose of the extension. The proper way to use this type of faucet would be to build out something on the inside of your home, which I'm guessing isn't possible, or at least unattractive in your situation.

Therefore, I'd recommend getting in the habit of shutting off the water on the inside, possibly replacing the shutoff valve with a quarter turn ball valve so that it's quick, easy, and obvious when it's been done. You want to open the outside faucets when the water has been shut off so that the lines are empty when they do eventually freeze. After they've been left to drain for a day, I cover my outdoor faucets with insulating covers. This is also a good time to drain the hoses and bring them into a protected location (e.g. a garage or shed).

1. Depends on the finish you select. A high-quality product won't be so dependent on a high-quality primer. The issue is mostly sealing, as the thin factory-applied primer bonds well, and facilitates a good bond with your topcoat, but doesn't necessarily seal well itself. Typically you'd plan on a re-coat after only a few years anyway to establish a hearty, protective finish.

2. I've never seen rabbeted siding buckle vertically, and I'm in a part of the world with extremes of temperature and humidity. Typically only thicker, more stable siding is rabbeted, and it's done so that the profile isn't so deep. There's really no drawback to it, in my opinion.

3. Cedar siding is prone to cracking along the grain if it's too thin. I'd be more concerned with the thickness at the top of the boards than the bottom. Ideally, you have a full 3/8" at the top. Some cheaper siding is barely 1/4", and you can feel the difference. If the boards are easy to flex across the vertical with your fingers, look for a better product.

4. Grade A (which I assume means "clear" in this case) will obviously be less prone to structural breakdown due to greater consistency. However, knotty cedar isn't necessarily a durability risk. Take a close look at the structure of the knotty boards and check for looseness and obvious weakness. When installing, cut out knots that look like they'll fall out--ones with sharp edge lines and which penetrate at a 90 degree angle.