Oven floor is too cool

Hello

I built a Allen Scott oven and have had a couple pizza parties, cooking about 25 pizzas in 2 1/2 hours. Oven temp was anywhere from 500-900 degrees. I baked pizzas with a small fire on the sides and back of the oven while pizza baked. Pizzas took about 4 minutes but the bottom of the dough was not getting crispy like it does in my conventional oven with a pizza stone…(The pizza tops at this point were on the verge of being burnt)

Any suggestions?