Question: What about flex PVC pipe? Why is flex pipe pipe recommended inside the attic?

Answer: Cementing pvc pipe and pipe joints together can be very toxic. This is especially true inside the attic which tends to be a very closed area without adequate ventilation. IF flexible two inch pvc pipe is used, there is no need for cementing pvc pipe inside the attic. This is because a continuous length of pipe can be used inside the attic and joined to rigid pvc pipe outside the attic.