Should an attic have a vapor barrier?

9/3/2023 at 9:40:43 PM

There are a few factors I would look for in this.

Let s begin with the simple ones;

Is there adequate attic venting? Do you have visible vents from outside that you can confirm are in fact cut through the sheathing into the attic? Is your soffit perforated, and are there baffles to allow airflow into the attic from outside? Is there Vapor barrier on the attic ceiling, or just the attic floor!!?

Where from is the furnace drawing air? Are pipes installed to draw outside air, or is it drawing from within the attic?

Is there also an A/C unit? If so, is the drain pan possibly clogged, leaking or overflowing?

Same question for the furnace; is it possibly leaking or draining directly onto your ceiling?

Is there any evidence of wet insulation below the furnace, or above the wet spots?

9/7/2023 at 2:06:15 AM

vapor barrier is always installed on warm side of walls or if its a attic ceiling that has no actual attic space left and it was insulated between the rafters...you are obviously getting moisture from another source, it is not he vapor barrier...You must have "no or improper" ventilation in the attic space and it is now condensing on vapor barrier warm side, You need a professional evaluation as too why you are not venting.