Moisture around can lights

Roofing/Construction Questions
1

I apologize in advance for the post, as i am a new homeowner with limited knowledge of home construction.

That being said, here is my issue.

I have recessed lights throughout my house. Several of the ones on the second floor now have water damage around them. I noticed about a month ago that the upstairs was much hotter than the main floor and much more humid also. I didn’t think much of it.

We have a new-ish home (4 years old) with a “flat roof”. First thing i did is called the company who put my roof on. After an inspection, he said he was having a hard time trying to determine how water could be getting in from above. He proposed that the can lights were just collecting condensation.

As a home with no attic, i am not able to get up in the space between the ceiling and the roof. There is about 2’ of space between the 2nd floor drywall and Roof deck.

So, i take out a can light and the can and the box with the electric in it are covered in moisture and the space and insulation is very humid and damp. Some mildew/mold growing on the OSB.

So, my theory is that humidity is rising to the highest part of the house and leaking out through the can lights. The super hot summer attic and the “colder” humid air is collecting on the metal. I have no other ideas as to how to diagnose the issue.

The only solution i can come up with is to insulate the light so as it slides up into the can, it is “air tight”.

But i don’t really know. I also am worried that this moisture has moved across the ceiling, as i am experiencing some bleed through mildew in other areas of the ceiling. the roof/ceiling is engineered OSB i beams, 12" on center.

My questions are:

  • has anyone ever experienced this?
  • what is the remediation plan?

Thanks in advance everyone!

2

Is there any ventilation in the flat roof? Sounds like you might need an exhaust turbine or fan in the flat roof.

3

No ventilation currently. I thought the all attics/space under roof needed ventilation, but as soon as i started asking around i was told that isn’t always the case.

4

We have ran into your situation before and solved it by installing turbine vents. Some people don’t like them and say there are better things out there. They do not require power and do not have motors to burn out.

5

I would like to introduce some ventilation. My understanding is that the roof deck visible by looking up through the hole for the can light is the “flat roof” and that there is a second roof installed on top of that with the pitch to drain the water.

Never had heard of 2 roofs on top of eachother until this home :stuck_out_tongue:

6

Yup, definitely sounds unique though.

7

I’ve seen pitched roofs built on top of a flat roof before, but not very often.

8

If the bottom of the roof deck when you looked up had accumulated moisture. Then the roofer did not install a 6mill vapor barrier as was needed.
If the can light was the only thing accumulating moisture. And the space had no other way for cold to get in. Then you roofer did not install or tell you that you needed to install the proper thickness roof insulation before the new roof.