Walls – Should I use sugar soap or denatured alcohol to clean nicotine from painted walls

Fisrt, DON'T REPLACE THE FLOOR, that would lead to a lot of headaches and is probably un-nessassary. That floor shouldn't absorb oil that quickly if it had been sealed properly. My guess is that the floor either wasn't sealed correctly or it's been so long since it has been that it's all been worn off.

Try getting a wood oil soap (like Murphy's or Old English) these soaps have oils in them that are meant to be absorbed into wood. This won't take out the oil, but it might help to make it blend in. I don't think that stain is comming out, even if you sanded the floor, the stain would have absorbed into the wood too deeply.

It's important to remember that wood is pourous and the natural oils that are in it are evaporated over time and have to be replaced, or else the wood becomes discolored and brittle, which is probably the case here. I wash all my wood floors twice a year with an oil soap to help keep them hydrated.

Painting a pressure treated wood deck is always tricky. Pressure treated wood does not seem to hold paint well, even with a good primer. Stain is usually a better alternative, but since your deck already has paint, it would have to be stripped completely before using stain.

In order for the paint to stick fairly well, the surface needs to be as clean and dry as possible. Looking at your pictures, I see a fair amount of algae in the grain of the wood. This is a very normal condition. You should however, use the pressure washer and bleach/water/TSP shrub down method to clean it up. I'd wait until April or May when temps are up in the 60's to 70's to help dry the deck and open the grain.

Select a high grip primer rather than a stain blocking type. Many manufactures have come out with new formulas that are designed to bond better. When you apply the primer, don't rush. Simply rolling on primer too quickly is not good. The primer needs to be brushed into the grain as deeply as possible. Let it dry completely. Now you can apply your deck paint as normal.