Under floor Insulation

[NRB]

We have a holiday house that is brick veneer on stumps etc. and runs east-west , the north part of the house gets good sun exposure but in winter very little sun( sometimes none) gets to the south facing side. As we are only there on weekends when we open up the house it often feels damp on that south side.
The house was built in 2001(which I was the owner builder) and after many years the soil under the floor slowly dried out as I would expect but over the past couple of years and the drought breaking (we are in south Gippsland which is know for lots or rain some times 20mm week on week) there is some dampness back.
My question is,would spray foam applied up to the floor boards,bears,joists etc. as well as insulating keep out this dampness?
After the house was completed and on suggestion after final inspection I put in several more under floor vents (approx.250 X 250) knowing that the vents that are just gaps between the brickwork at floor level may not be enough, so I think that under floor air circulation is not too bad.
I see on many of those USA building shows that spray foam is used a lot to keep out moisture and question is that used here in Aus.
Thanks for any advice:)

[NRB]

For those who have been looking at my post,I have found a supplier who will spray foam 25mm of closed foam which will stop moisture and also insulate.
There is a DIY kit you can get but it is more expensive (and a bit tricky,cost a lot more if you don't get it right) than having done by the Pros.

[Larry McCully]

No, I am not a big fan of spraying foam on joists or framing members where there is a possability of future moisture containment.
As far as your sub floor is concerned. You can find on the web information on the amount of vents needed per sq mt of volume of space under the floor. As long as you have adiquite venting, you will never need to worry. More venting is good.