Scaffold board for outdoor bench - treating required?

Along the river towpath near where I live a bench has lost its top, literally a plank nailed on to two wooden posts. I want to replace it as a bit of a gift to the community. This is not my strong suit - can I just use a brand new 38mm scaffold board (it's about the same dimensions as the plank that has been destroyed)? Do I need to treat it with anything, or am I better off going for reclaimed oak or something?

Also, is it better to use galvanized nails or screws?

Thanks!

 

Depends on the span, scaffold board may be too thin.

 

About 190cm

 

I wouldn't waste money on oak if you think it's likely to be stolen or vandalised. Yes, it's worth treating. Nobody wants to sit on a damp, splintery plank.

 

Too thin

 

How about using 2 boards
And make sure you sand it down well on all accessible edges.

 

the span in this instant is the unsupported distance between supports
is that still 1.9m ??

 

Thanks all for your input so far! Sorry, I misunderstood. The span would be 130cm.

 

Use shuttering boards -- they're generally 9" x 2" and come in various lengths. Where I am I can get 6ft lengths for £4 (used) and any good reclaim yard sell them.

Give it a sand and wood preservative and it'll last years. I'd just drive 4" minimum self-driving decking screws through it into the posts.

 

untreated scaffold boards would be fine would expect at least 5 years possibly 8-10+years as long as it gets the sun or wind to keep the moisture content changing

 

Thanks! Might just go for those for simplicity and cost reasons, then!

 

An untreated sleeper would be more sturdy

 

Seems like that would need some much heavier duty fixings as well, though?!

 

Yes but would look way better.

 

Suggested fixings?