The pic on the left is my flat prefold in tri_fold. The pic on the right is my prefold hybrid (inside a diaper).
The tri-fold is used to turn a pre-fold into an insert, for extra absorbency in a diaper. The are used in all types of dippers as a soaker layer, especially for overnight diapering. a Tri-folded diaper is also common as the insert for a pocket diaper. To be honest I don't see my prefolds being used as a soaker layer, they are just way thicker then needed as an insert in a regularly changed diaper (except maybe at night for a heavy wetter). The would be great as the insert in a pocket diaper. I'll be making 3 layer flannel inserts anyway. So why share this? Any cloth diaper Mom should be aware of the tri-fold because it is useful, especially in a pinch.
Tri fold is simple:
1. lay diaper flat.
2. fold 1/3 over.
3. fold other 1/3 over.
Now you have an insert for a diaper. When done with my hybrid, the tri-fold curves up into shape of baby.
Yes that was simple. The other folds are simple as well. Not fold in 1/3rds, but still very basic. Next will be the Angel Fold.