A few years ago we tore down our wooded deck and built a screened in patio with steps leading into the kitchen. The concrete on one side of the patio extends about 2.5' beyond the screened-in portion. The roof overhangs a foot or so of this. My kettles and WSM are stored on that side of the patio/porch.
I normally cook on my kettles at the same placed they're stored. I normally move my WSM into the yard on a long oil drain pan to cook. However, if its raining or I'm cooking over night, I bring the WSM into the screened in portion. The porch is pretty large and there nothing on it except metal and glass table and chairs. Not worried about fire, but wouldn't want to cook inside the porch very often because of smoke. Haven't noticed any but don't want to push it.
I almost burned a wooden deck several years ago. My grill had rusted through a bit (non-Weber) and a couple of coals fell through. My SIL noticed smoke while we were eating and asked what I had on the grill. Went outside and there were a couple of holes burned through, one about the size of a softball. That could have been a disaster.