So, I’m on our neighborhood FireWise committee here in Austin. The training we have received indicates that the primary direction that embers would be coming to

So, I’m on our neighborhood FireWise committee here in Austin. The training we have received indicates that the primary direction that embers would be coming to your deck would be from the top side, not the bottom. So, sealing the bottom doesn’t help you, but making sure the top side is properly sealed will help. Of course, you do have to worry about things blowing under the deck, but there the solution is 1/16th inch metal screening at the perimeter of the deck to keep the embers from getting anywhere close to being under the structure, as opposed to sealing the underside of the deck. You are correct that in most residential wildfire situations, the primary concern is embers. We saw that in Steiner Ranch. But there are many other factors, too — like all those wood fences that act like a wick to take the fire from one house to the next to the next and so on. Or your proximity to the WUI. Or many other things. If you haven’t checked them out before, I highly recommend the FireWise resources at http://www.nfpa.org/Public-Education/Fire-causes-and-risks/Wildfire/Firewise-USA http://www.nfpa.org/Public-Education/Fire-causes-and-risks/W...