To prevent a soggy pie crust, bake the crust prior to filling it with your preferred filling, also known as a blind bake. Additional preventative methods include brushing the crust with egg or chocolate or baking it on a hot baking sheet.
If you choose to use the blind bake method, you can use pie weights to keep the crust from bubbling up during the cooking process. In addition, you can either bake the crust completely or partially, depending on the type of filling you are going to use. If you are adding a cooked filling, a complete bake would be acceptable.
Brushing the crust with egg or melted chocolate creates a barrier between the filling and the crust. To use the egg method, combine a whole egg or just the egg whites with a bit of water, and brush the liquid directly onto an unbaked crust prior to adding the filling. The chocolate method is to be done on a blind baked crust that is cooked thoroughly; allow the chocolate to completely set before adding the filling.
Another way to prevent a soggy pie crust requires you to place a baking sheet into a hot oven, giving it time to heat up. Once it's hot, place the pie dish directly onto the hot baking sheet. This method melts the fat content within the crust quickly, allowing the crust to set quickly before the filling has time to seep into the raw dough.