I have a brick oven attached to the back side of a cherry on my house. I've dreamed of cooking pizzas in it so I built a huge fire in it the other night and had a bunch of friends over to eat. I built a fire on one half of the oven thinking I would cook pizza in the other half. I used an infrared thermometer to measure the temp of the floor of the oven and after several hours of burning a fire the temp was only up to about 300 degrees. I touched the top of the outside of the oven (like an idiot) and burned my finger bad. It's obviously not holding heat. It appears that the oven is only made of the same bricks as the house. Also, the roof seems to just be a cement slab. You could see she pouring through it when I had the fire going (smoke also poured out the chimney). What's the best way to insulate this thing so it will hold heat. It is a pretty large oven compared to the over traditional pizza ovens I've seen on here. How long should it take to get the floor up to 700 degrees? Thanks to anyone who can help.