I am in the process of building an ICF house in North Texas (DFW) (not a DIY). As this area is quite prone to tornadoes, I want a concrete roof besides ICF walls. The city where the house will be built requires a minimum pitched roof of 7/12. Assume a ceiling area of 2000 sqft. I would also prefer a flat ceiling below the pitched roof. Also, the roof has to be covered with slate, tiles, seam metal or shingles (I prefer the last 2). I think seam metal can be directly applied over concrete (correct me if I am wrong). I will have mini-splits so no HVAC ducting is needed.

I have been reading this forums, googling and researching for quite sometime now and here are the options I can think of:
1. Use InsulDeck or Amdeck etc. to create a pitched roof and use wood joists to create a wooden ceiling underneath it.
2. Spider Tie - but I am not sure if it can stand tornado strength winds and the whole process seems very labor intensive. You need an engineered truss etc. too to support the weight, a slight overkill for my needs.
3. Use InsulDeck or Amdeck etc. to create the ceiling and a wooden roof above it which I could lose during a storm. (Not sure home insurance companies in Texas give a discount on concrete roofs - if so, I may lose that here).
3. Create a concrete slab ceiling and a wooden roof above it which I could lose during a storm.

Which option makes more sense in terms of cost and storm protection? And among the ICF roof options, what are the best options. I am in touch with ICF installers who have worked with InsulDeck and Amdeck.

Thanks.

My vote would be for a concrete roof. I don't see any point in having your roof blow off if you are willing and able to pour concrete. You might want to read this GBT thread:

Pitched Insulated Concrete Roof Taboos!

Thanks for link. I will check out WRCS. That's a lot of roof with no beams. I like the joist idea to create a rafter too.

Anyone knows how wind tolerant Spider Tie is compared to ICF roof (Insul-Deck etc.)? Also, what's the cost comparison between the two?

Thanks.

CuriousTexan, We have recent DFW area work with Insuldeck, Spider Tie (closer to Houston actually) and concrete ceiling slab with wooden roof above (in work now in Springtown (near Fort Worth). If you'd like to talk to any of these owners or installers just pm me or go to the futurestone website and contact me. Regards, Cameron

Don't know on the pricing. But, since Spider Tie is essentially an ICF system, and gives you a solid concrete roof tied into your concrete wall system, it'd be as wind resistant as any other concrete roofing solution.

Going to assume you've already seen the video on YouTube: https://youtu.be/HVWS47MxnwI

Yep, saw the video. For a mini-split system without a need for huge attic space, its seems a bit excessive in terms of time and labor involved.