Replies

1. 
   cdanner | Sep 17, 2022 02:13pm | #1

   I was also considering large tile on the interior of the walls. Cement board and then tiles in a gray color similar to what cement would look like. And then all new drywall beautifully mudded throughout the rest of the house. It's a Japanese aesthetic we love, so this should help protect the interior from heat.

   But I'd still welcome your thoughts on cement board on the walls. Thank you.

2. 
   mgmahan | Sep 17, 2022 03:49pm | #2

   Insulation will not help. Anything you do inside will not help. https://codes.iccsafe.org/content/CBC2019P4/chapter-7a-sfm-materials-and-construction-methods-for-exterior-wildfire-exposure

3. 
   SheilaFett | Sep 22, 2022 11:18am | #3

   Cement board is ideal for applications where moisture or extreme climate are present. Cement board can be used on exterior walls where water damage is a concern. I'm not a fan of building with cement board in extreme climates. Last summer I put it up on my house and it was a pain to work with because of the high temperatures. On the other hand, cement board is stronger than some other sheathing materials. With the right fasteners, you can use cement board in the attic if you are concerned about the plywood or OSB being punctured by the fasteners. You cannot use cement board on the interior walls. It is a moisture barrier, not a sound barrier. It is also a thermal mass and would cause problems with freezing and thawing. It's not a good idea to leave it without an interior finish.

4. 
   rww0002 | Sep 26, 2022 10:49am | #4

   mgmahan has given you the best reference I know of for fire-resistance.

   One thing to consider is that many of the most efficient insulation types perform very poorly in fire. Blown cellulose and foam insulation especially. Most of the foam or solid insulation types (spray foam Poly iso, XPS and EPS) are basically solidified petroleum.. not awesome for wildfire-prone areas.. I would stick with mineral wool and fiberglass solutions.

5. 
   florida | Sep 26, 2022 02:42pm | #5

   You need cement or clay tile roof shingles, steel window shutters, & trim or stucco. Sprinklers on the roof would be a big help as long as you have a reliable water supply. None of that will guarantee your house won't burn in a big enough fire.

1. 
   mgmahan | Sep 26, 2022 02:52pm | #6

   Actually composition shingles have a pretty good fire rating

1. 
   bing0328 | Sep 26, 2022 05:50pm | #7

   Don't hold a candle to concrete tile, sorry to say. Florida is right, sprinklers with a very reliable supply together with enough water pressure is your only hope. Better yet don't build in a fire zone.

1. 
   mgmahan | Sep 27, 2022 10:50am | #8

   Class A is the highest rating, offering the highest resistance to fire, and unrated is the worst. Examples of a Class A roof covering include concrete or clay roof tiles, fiberglass asphalt composition shingles and metal roofs.