Fire separation distance (IRC2021 - R302)

[taz112358]

I'm getting ready to plead my case or negotiate with the code official and I'm hoping I have a decent chance to overturn their original comment.

I've got a two story house on piles, the first floor starts at 9' above grade. I have a non-conditioned area below the house partially enclosed with wood louvered walls - popular with beach houses in the area. Since the lot lines are really tight, we are at 3' and some change from the property line on either side. On the upper floors I've got 1HR fire walls and meeting <25% openings. But on this first floor they are asking I put the firewalls here too. I can't enclose this space or it will be unusable most of the year since it's unconditioned and I'm on the coast in Texas.

I'm hoping to either drop back my louvered walls 2' inside of the structure and get 5' away from the property line under here, or just do away with the walls all together. Putting fire walls there is not an option to the owner, he knows it's just going to get hot and muggy under the house with full walls there and end up being a problem. I agree.

I guess you have to pay for a subscription to ICC to get the commentary or something. I don't know if it's worth it to see if this is even in there.

Any ideas?

Thanks in advance!

 

[taz112358]

Well it didn't work. They consider the open area under the house a wall opening so it's got to be a 1hr firewall if it's within 5' from the property line.

Oof

 

[phamENG]

What about proving the piles are 1 hour rated using heavy timber design principles and providing a 1 hour rated floor assembly above? Then use PVC boards or other non-combustible materials to build the louvers?