I have a whole wall that I need to block off with some sort of door. I'm thinking that a bi-fold door would be awesome. However, my husband kind of wants a sliding door. I just think how cool it'd be to have a whole wall made up of a door that could easily be tucked away when needed. This would make outdoor barbecues a lot easier. It would sure save me from having to open the door every time. http://www.superiorwindows.com.au/content/Products/BifoldDoors.aspx 

As an manufacturer of bifolding doors, this is always a discussion point with our clients - there are a range of choices Crimsafe make a bifolding security screen door - functions like a typical bifold but with the added security that only Crimsafe can offer There are retractable insect screens like Freedom, which we have used on several of our bifold installations, through ti Centor Or if you are really adventurous you would use an air curtain, above the bifold to deter the flies from coming in to the home at all (if you do a search for air curtains on google you will find a vast number, used extensive in commercial applications but creeping more and more in to our homes Enjoy your wide open space that your bifold will create - www.centralglass,net.au

I couldn't tick one or the other of the boxes – I think the choice has to be made contingent on so many variables. In fact we have painted timber, double-glazed bifolds (with a fabulous retractable pleated fly-screen) at the end of the dining room leading out onto a terrace and a painted timber, double-glazed slider (with a timber-framed sliding fly-screen) on the other side of the kitchen (but on the same axis) opening onto a raised timber deck. Each works really well in terms of function and aesthetics but they would not be interchangeable as the different locations determined which was more suitable – but they have been made by the same highly skilled window craftsman and have given us nothing but pleasure. And on a hot, steamy evening with both open we have the most wonderful cross ventilation.

i would be surprised if the floor under the old verandah is properly constructed to avoid dampness and "raising the roof a little" and adding footings just under the doors is not as simple as it sounds ... i would have a builder check to make sure that the preparation is done properly before considering the bifolds..no point investing in expensive new doors and internal new finishes if the floor is likely to be damp