Would you say sheetrock slows down a fire, or makes no difference at all? How about fiberglass roll insulation? I have a fair amount of exposed wood contruction in my house (large crawl spaces and attics). I don't intend to finish these areas, but I'm wondering if it would be good fire protection to insualte nd sheetrock some of the larger more exposed areas. I'm also trying to figure out if a closed, uninsulated wall will harbor a fire any better than an insulated wall. Way I see it, there's a finite amount of air to be used between 2 studs that are 'rocked on both sides from floor to top plate. With insulation, there's less, but does the insulation really make a difference in retarding the fire. Just wondering... This house has had a fire in the past and didn't seem to be damaged too bad by it, barely structurally at least.