Wood Sub Floor Timbers in Lounge

[onabudget]

Hi All

I am replacing some timbers in a sub-floor over a solid concrete base, the current one's are 3" by 3" so want to match as much as possible but cannoty see much 3" by 3" on sale so contacted some sawmills, one close to me produces treated fence posts up to 3.6 metres which would be perfect.

I'm assuming this is not kiln dried but is treated, would this be ok, I am assuming other people use this for similar things as it's in lengths up ti 3.6 meters and thats a bit long for just fence posts...

link to it below? hope I'm allowed to add link as I don't work for them, I don't have any interest in them except for buying some of this if it's the correct type of wood

http://www.beaumontforest.co.uk/tim...ls-accessories/treated-fence-post-75mm-x-75mm

basically I want to have some frame sections of this covered with sheets of ply, to replace the part that has rotted/cracked over time, would this be ok for the job?

thanks

thanks very much