I volunteer for a Georgia association that has a little over 2 miles of trails around a lake with some “low country” areas.  In the 80s they built a sort of boardwalk in the low-lying areas constructed of pressure treated framing (usually 4×6) and landscape timbers for “treads”.  These were built in the low (wet) areas the framing is rotting away on much of it.

We want to replace the “boardwalks” but haven’t found a good design for something new.  There are a lot of composite products that could replace the landscape timber treads, but they still recommend framing with pressure treated?  We also need to design a way to anchor the beams – in most areas they were just layed over 4 x 4 stacks.  

Trying to find something that will look natural but resist rot.

Any advice appreciated.  Thanks.