[eremite06]

I just noticed a water stain beside the dining room A/C vent. I remembered reading about a defective "grey" plastic ridge vent made by Alcoa. Mine are plastic also, but are black in color. I would suspect this plastic will break down in this summer heat. I think when it rains sideways at times the rain has to come through these vents. I checked the attic and the truss above the suspected leak. It does look like the metal truss strap is stained by moisture.

Anyone have this problem or replaced their black plastic ridge vents? I live in Lynnhaven.

[Ooper]

You ridge vent may or may not be defective but I doubt that it is. Ridge vents are designed to be very efficient, even in "sideways" rain. I would suggest that you have your air conditioning ductwork inspected as I suspect this is the cause of your water stain. Many times, if you ductwork or the insulation around your ductwork in not correct, the cold air will cause condensation to accumulate on the ductwork in the warm humid attic spaces in the summer time. This condensation will run down to the diffusers and can cause stains and other damage to the surrounding area. This happens frequently in bath and shower areas also.

[eremite06]

Thanks, Ooper. I checked the duct work and the only insulation I have around the diffusers is blown insulation. I did feel moisture around the outside of the vent. Should there be bat insulation around each vent to prevent this?

[eremite06]

I just called an A/C insulation company. They said I should have a 2 in. thick rap of insulation around that terminal box attached to the diffuser in the ceiling. Makes sense that a cold metal that's not insulated will weep condensation when exposed to warm humid air. I am 4 years out of warranty and the builder cut some corners at my expense.

Anyone who notices reddish/brown stains around their A/C vents, check to see if the terminal box is insulated.