OUTDOOR ROOM - Flooring options

Hello - first time forum user needing help - Can anyone offer some suggestions for flooring options for an outdoor room?

I am planning to build a deck/outdoor room - 4m x 9m. I live on small farm and would like it less 'gappy' as mozzies, snakes are a concern. I will eventually screen the room and add louvres on the weather side.

What is the min spacing between decking that I can lay? T & G concerns me that it may be subject to some weather and may open up. Cement sheeting/tiling could be an option, but I like the natural timber look. Ply?? Not sure? Does it last - look OK?

Any new exciting options out there that I dont know about? Please help.:C

I don't think ply is suitable
I'd lay some flyscreen under normal strip decking. Normal gap is 4 to 6 mm.
I wouldn't reduce the gap as if it gets wet and swells it could damage the complete deck.
It means dirt won't fall through so you'd have a little more work cleaning but should control mozzies and small snakes.

I used to live in a farmhouse in far west NSW. Part of the 3m wide screened verandah that went right the way around the house had been there since the 20's....the other portion since the 60's.

All of it was tongue and groove floorboards. The only maintainence it ever got was a routine sweeping/vacuum and the occasional dose of tung oil. The only parts that were damaged were the last foot of the end closest to the screen (mostly sun and water marking) and the worst damage was in those parts of the verandah where the boards had not extended under the knee wall under the screen....so the end grain had been exposed to the elements. However, none were so far gone as to be stuffed or dangerous....not bad for over forty years of exposure.

As a result of this experience, our new outside room will be a 5mx9m screened space with recycled 19x100mm T&G hardwood floorboards with an oiled finish. Wide eaves will be used to mitigate the worst of the direct sun and water that might come their way.

T&G ply is certainly an option but it'll need to be sealed (oiling is not enough).......which might make it slippery

A lot of the old Colonial houses had T&G verandah decks...I guess you have to have a minimum fall of around 1:200 with the joins running with the fall.