Answers

Depends on how dirty they are. If there is a lot of dirt and dust, yes. If they are just in need of some minor blemish touch up and rough areas, they should be Osborne brushed first then stain. The less water the better.

A month or so should be fine.

Per they label on the Boracare.

Never heard of it. I would be concerned also. Use a good latex stain for log homes.

You will have to strip it and start over again. Use a good quality latex stain made for log homes. I prefer Life Line.

Verticals are real tough to replace logs. If they are rotten along the bottom it may be better to cut lower area and replace with a treated 2x material, doubled up. Get gutters on it! As for the varnish it will have to be glass blasted, sanded and then stained.

Different chemical make-up to put up with standing water and foot traffic. Deck stains should never be used on a horizontal surface like a wall.

You only need to stain exposed side. If it is rough saw, you could use Sikkens. If it is smooth, you should sand lightly with some 80 grit to break up mill glaze and then use Life Line. Call Timeless Wood Care at 800-564-2987 for the materials you need.

Won’t bother the logs, but the smell will not be fun. Also, it will probably wash off the house over time and leach into your ground water. Just a couple of gallons of diesel fuel is considered a toxic spill!

It should work to prep the surface, but it will not strip the old stain. It will probably look a little blotchy, but will be protected.