Question about separation and building house

Hi guys & girls

I have separated with my wife a few months ago.  We have an acreage, its under both our names.  Just before xmas my wife said she would like to sell it and I said I want to talk about it in the new year as we bought it because we both loved the property and it was for us and our two kids to live on.  Anyway, now Ive found out that she is getting quotes to build a house on it.  She hasn't said anything to me about it, I was thinking, woohoo, maybe she is having thoughts of getting back together and living on our property, but then the negative part of me thinks, could she be thinking of building on it and buying me out of it?

I would like to know legally though, if she is able to start building on that property without my consent?  Would the builder want both of our signatures to start?  Or would it be the shire that would need both our sigs?  

I'm a bit confused.  Yes I could ask her but its not on the cards right now,

thanks in advance

kind regards

Justin