Yes, a seller is legally required to disclose any known fire damage when selling a house, including damages that were repaired. That includes damages to structural components and all major systems, as well as water damage, chemical damage, and smoke damage related to the fire. Sellers use a property disclosure statement, which is regulated by each state individually, to disclose fire damage.

The timeline for fire damage restoration varies significantly, from a day or two to over a year, depending on the extent of the damage. For minor incidents like a small cooking fire, cleaning up soot and removing smoke odors may only take a day or two. Repairing minor damage might take about one to two weeks. However, a major fire requiring structural repairs, full property renovation, and replacement of materials can take anywhere from six to 12 months to over a year. This longer timeline often includes waiting for insurance approvals and contractor scheduling. It's best to consult with your insurance provider and restoration team to get an accurate timeline for your specific situation.

Baking soda is an effective fire reduction method. However, flour and baking powder are very dangerous around flames. Flour is flammable and it can also conduct electricity. The combination can cause serious injury from electrical shock and worsen the situation by adding fuel to the fire. Baking powder is also not an option as it's also highly flammable. 

Homeowners insurance does not cover DIY mistakes, so tread lightly if you plan to tackle your own home repairs or renovations. If you cause damage to your home while attempting repairs or renovations yourself, the cost of fixing the damage is often considered your responsibility. Most policies only cover damage caused by covered perils like fire, theft, or weather—not by homeowner errors.