I usually keep a baking tray in the oven when I light it, and then put the pie tin/plate straight onto the hot tray - this means that the bottom of the tin gets enough heat to cook thoroughly.
Agree with jamesnan; heat a metal tray or pie tin first, then put pie on that when it goes into the oven. Also, metal is better for pastry than using a "plate" ie, I assume porcelain.
For pies with a 'wet' filling it is a good idea to 'Blind bake' the bottom first . Just enough to set the pastry, not fully cooked, and then put on the filling and top.The way you would do a flan case.