Log Cabin Playhouse

Submitted to Community Café

I'm working on a log cabin playhouse for my granddaughters. The "logs" are landscape timbers. They come flat on two sides, but I ripped one of the round sides off to make them all the same thickness and give the interior a flat surface. I later used the edges I ripped off for lap siding on the loft ends. The timbers are treated, but not the same as pressure treated lumber. Halfway through the project, the place I was buying timbers from originally almost doubled the price, so I went to another source. They were the same species (Southern Yellow Pine) and practically the same size, but the color was different. The first “logs” have a much greener tint than the last batch I used.

Once I get the rest of the windows installed, I would like to do something to the logs to make them a little more uniform in color (and maybe a little less green) but I want them to look as natural as possible. I don't want to paint them. I would also like to seal them to help protect against water damage. Any recommendations on what product(s) I could use?