Decks, Patios, Porches and Docks - Refinishing exterior timbers

I want to re-treat the exterior beams on an old house. The eaves are large rough cut open grain beams originally treated with creosote. They are dark brown to black but show some bleaching and wood rot where they have weathered.

I would like to preserve and stain the wood with the same product if possible.

I have two copper-based preservative products I am looking at, one is an oil/solvent base with a green tint, the other is water base light brown. Once applied they will both repel water somewhat making it difficult to stain afterwards. I want the preservative to penetrate as deeply into the wood as possible, but the same is true for the stain. The best option seems to be to mix in a colorant.

Assuming I want a walnut brown to black result, what would I mix into an oil/solvent product? What would I mix into a water based product? Something that fully dissoves and is cheap is preferred.

Welcome to the diy forums!

Cresote isn't available anymore. I'd be leary of applying latex over cresote.

I'd recomend going to a paint store and getting an oil base stain tinted to the color you desire. Be sure to let them know that it will be going over old cresote.

A stain alone does not provide much insect/fungal control, and mixing equal amounts of stain+preservative would probably result in something that does neither well. That is why I thought to get a concentrated colorant.

What I have found is the universal tints, aniline dyes, colorants for dark brown to black are either expensive, or they are restricted use (coal tar, creosote). I read where some finishers have used india ink, but I assume this will only mix with a water base.

There is a product, Woodlife Creocoat, which is supposed to preserve and stain black at the same time. This may be the best choice.