I don't know what was done to it when it was brand new. I have stained it twice, once about 7 years ago and once about 5 years ago. Going by the partial cans in the garage and my own memory, the first time was done with a Behr transparent oil-based stain and the second time with Behr semi-solid urethane-enhanced acrylic stain. I don't recall doing much of any prep before either project.
The stain is actually in pretty decent shape considering I apparently put water based over oil based with no prep. The horizontal top of the fence is pretty much devoid of stain at this point and there is a fair amount of green mildew, but for the most part the vertical boards are looking decent.
This time around I've done more research, but in some ways it is only serving to confuse me. So far the plan is to pressure wash, hand scrub away any remaining mildew with a bleach solution, let dry, then stain. But:
how long does it take for the wood to be dry enough? This is Oregon, if we prep it one weekend it is likely to get rained on before the next weekend. But I'm guessing that doing it the next day may be too soon.
do I need to sand off the old finish in order for the new one to take properly? I would really rather not do this, partly due to the effort and partly because the boards are rough-sawn and I don't want to lose the texture. But I don't want it all to peel off right away either.
I've read conflicting reports of whether a colored stain needs to have a clear coat applied over it or not.
It seems that every brand of stain out there has it's fans and detractors. How in the world do you pick the best of what seems like a sorry lot?
In case it matters, I plan on using Woodmates stain applicators (pads) this time around, instead of brushing as we did last time. Also, I don't know what kind of wood it is - the posts look pressure treated but as far as I know the rest is not.
Any advice would be most welcome!