This strong, sturdy seam construction is used for sportswear, men’s sport shirts, children’s clothes, and pajamas. Garments which will receive a great deal of stress or must withstand repeated washing will be sturdier if constructed with flat-fell seams. However, avoid using the construction on bulky fabrics; the seam is think and difficult to construct in a heavy, bulky fabric.
Place the pieces to joined wrong sides together, and stitch a plain seam. Press the seam to one side and trim the lower seam allowance to 1/8 inch. Turn under the raw edge of the other seam allowance and place over the trimmed edge. Stitch close to the folded edge through all thicknesses.