[rfuerst911sc]

I have a detached carport that I store my RV project under. It is aprox. 14 ' wide x 20 ' deep. I layed down pressure treated 4 x 6 around the perimeter and the metal framework of the carport sits on top of this. So I basically have a 3.5 " tall framework around three sides. This is all on hard packed Georgia clay. Been in place for a year now so everything is settled/solid so now I'd like to have a black top company come in and put down a base. Other than getting rid of grass/weeds is there any other prep I need to do ? Is 3.5 " of blacktop good enough or do I have to dig down some and put a gravel base ? We don't get harsh winters so not concerned about frost heave. I'm thinking blacktop will be cheaper than concrete is that correct ? Any ideas how much this should cost ? This is an open storage space meaning it just has a roof no sides/front/back it is just for protecting the RV from rain/sun/minimal snow.