Hi there,
I am about to build a deck. Sorry for the big speil but want to let you know the exact situation I am asking about.

We recently found termites in some jarrah about 1m from the house. Had it sprayed and removed. I am now about to cover the once infected area with a deck. To have total peice of mind (and to keep the mrs' paranoia at bay)I have decided to put a metal substructure down for the posts(piers), bearers and joists.
I have a friend who has done two decks before. He used batu (balau) and a nail gun with wood substructure. He told me some of the nail entries split a little but it was ok for him. The only thing is that he made these decks for two investment properties which he has now sold - so long term looks and use was not in his equation.

I have just had a patio put up in an 'L' shape with a nice bay (stop sign type) feature - (see attached pic - on its side due to restrictions of site upload specs).
I plan to do cement footings and either lay metal piers in the concrete as I fill them or dynabolt them onto the footings once set. the ground is very flat and as you would expect from WA, Perth the ground is very sandy and non-shifting (ie. compared to clay).

What I would like to know is the following in planning my deck and hope you guys can help...

1. Is Batu wood good for external decking with a patio metal roofing - it will get some spray on one weather facing side and some morning sun, but not in full sun. I would prefer Jarrah but it seems that batu is less expensive and a ok alternative.

2. Is Batu so hard it would be hard to use a nail gun and predrilling would be a mission? Also does most of the batu come from Indonesia or grown here? I have heard that some batu is grown here in plantations. If imported from indonesia, I fear it may warp due to different humidity conditions in Aussie. Any one had any long term experience of what it does after a few years?

3. Nails or Screws ? - friend has nail gun I can use so intial purchase is not an option, but I want a beautiful job so I am leaning toward stainless steel screws - +ve's - better fixing, longer lasting, no cracks -ve's - more expensive, more labour time, have to countersink, not sure if I want to see screws everywhere. So what brand or type of screw would suffice, or could I used a combination nail gunning the middle to keep it there at first and then come back later screwing the ends down.

4. If I did decide to go with screws, then would I need to place them at every joist intersection or seeing they are stronger than nails, at the ends and every second joist perhaps?

5. Not sure if I will save money in piers/stumps by attaching the deck to the house wall or make it free standing? I am thinking that there will be extra costs in having a row of stumps/piers along the brick wall, but thought that maybe it may be beneficial on one side of the house to have it freestanding as I have plumbing I need to get around (see attached pic). Mate told me negative of stumps right near house is your always find bricks,limestone footing, pipes near the house so they are harder to put in there generally.

6. In my scenario (external deck using batu with metal roof over it - getting morning sun and 4 metres or so may get some rain - but in Perth rain is few and far between ) would it need to be treated with a deck oil, etc or would it be fine?

7. I thought it would be best to buy the decking at the size of the longest part (10m approx) down the side of the house. My thought was to buy 3.6m lengths so the long part of the deck which spans 3.5m would be easiest using just one length - fair assumption?

8. Following rom Q 7..This means that the board would be going away from the house as opposed to paralell. Is there any rule about what way joists and the decking should go relative to the house, or is this just personal preference?

7. Any lastly I may go to an auction tomorrow to potentially bid on this - 1 PACK OF 90 x 19 BATU REEDED DECKING 240/3.65 876LM 78.8m2. My square meterage is 71.5 m sq. Does anyone know a good price for this?

Thanks to all that reply - lot of questions, but I am sure there are guys here that are very knowledgeable and can help!