Would there be any advantage to applying (2) coats of sealer / preservative to the deck after all preparations are made?

Is there anything special that needs to be done when refinishing a deck that has 2 stain colors in it? We want it to look uniform through out.

I put some rugs on my wood deck and the color from the rugs has left black stains on the wood. How do I remove these stains?

I applied a solid deck stain by Sherwin Williams, color grey, within 6 months it started turning black. What caused that?

I began to stain my new outside deck. I had a family emergency and could not finish the job. I went back to finish and I guess it was too cold outside because the layer I put on the second time became all white and crusty. Now the temperature is

Where can I purchase trisodium phosphate to treat a mold problem on my back deck?

Do I go with the grain of wood when sanding the deck?

Can I use the same exterior primer and flat paint I purchased for my house on my back porch which is a pressure treated wood?

I’m still not sure what to use on my exposed ext back steps (there are 4 steps). I plan to sand them down to good wood. The tread will be gray and the risers white. They were painted with alkyd 14 yrs ago which lasted 9 yrs. Then 2 treads

Can I paint over varnish as long as it is scuffed and rough edges sanded? Would I use an oil base paint?