"dg" wrote in message
...
Floor boards will contract and expand differentially and the resulting
gaps
will look rubbish.

The answer to that is to chamfer the edges, so that the gaps look
intentional.

As Grunff says, pressure treated timber will last far longer, but I would
also suggest that, if you do use that, also use a nail that will last too. I
made a couple of gates over 20 years ago with pressure treated timber and
bronze ring barb nails, from my local yacht chandler. Apart from needing to
replace some of the weather edge along the top, they have hardly needed any
maintenance since I put them up.

Colin Bignell