Thread: rings around attic recessed cans

hey all

saw this today in attic--moisture stains around all recessed can lights and in second picture around bathroom exhaust fan and plumb vent. is this just a poor can installation.
thanks cvf

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Either warm moist air flowing from the house in the winter and condensing when it hits the cold winter attic, or warm moist summer air condensing when the cool conditioned air from the house hits it.

Probably the former, but either way it appears it is due to non-AT cans or insufficient insulation.

I would check the label in the can and see if they are installed properly.

Not sure what the codes in CO are, but appears to be a relatively new home, I question whether they met code when the house was built.

HEY ALL

ANY help here

cvf

What kind of cans are they? Manufacturer and model.

tr

don't know did not move insulation to check

cvf

Blown cellulose is treated with borax or phosphates to discourage bugs from munching on it and it acts as a flame retardant. When it gets wet, the salts leach out leaving telltale marks similar to what you have presented here. It also results in the cellulose being no longer protected. My guess would be high indoor Rh% exfiltrating into the attic at the points where this is manifesting.

Need to replace insulation and, more importantly, seal attic bypasses correctly. Now, for 'can'-type ceiling lights, your replacement should be with ICAT fixtures only--no boxed covers, which are a fire hazard. The rest of the air bypasses can be easily sealed with a number of materials such as Thermo-pan, Thermo-Ply, etc. sealed with duct mastic.

HTH,

HEY ALL

my client had an electrician go to house and he told client everything was ok and to code--so it's on his back i guess--now this was a pre-listing inspection--so we will see what buyers inspectors says

hey any sparky here comment on this----i've been in 1000 attics and have never seen this--white rings means moisture to me

chas

Originally Posted by CHARLIE VAN FLEET

HEY ALL

my client had an electrician go to house and he told client everything was ok and to code--so it's on his back i guess--now this was a pre-listing inspection--so we will see what buyers inspectors says

hey any sparky here comment on this----i've been in 1000 attics and have never seen this--white rings means moisture to me

chas

I agree with you. I wouldn't omit it from the report. Electrically everything probably is fine, so the electrician could very well be correct in saying everything is ok. It is usually the GC that is responsible for maintaining the integrity of the vapor resistant barrier. The questions are: 1) Are the cans AT type? 2) Is the proper foam seal between the trim and the ceiling (or is the can caulked to the GWB)?

I think you have a good catch.

Originally Posted by CHARLIE VAN FLEET

hey all

saw this today in attic--moisture stains around all recessed can lights and in second picture around bathroom exhaust fan and plumb vent. is this just a poor can installation.
thanks cvf

I think Bob Harper is right. Moisture moving through the insulation could bringing up some of the chemical treatment in the insulation to be deposited on the surface. Heat from the lighting would "push" this moisture away from the heat toward the colder insulation and result in its deposition in a ring around the heat source. Better sealing of the ceiling penetrations as Bob suggested should help if its in face moisture from the living space moving up into the attic.

I confess that I am not a big fan of cellulose insulation for a variety of reasons. I guess I can add this to the list though I confess I have never seen this particular situation before on any of my inspections. Maybe its a "cold climate" thing but I gather this is an usual find even in your area Charlie?

The photos are consistent with moisture migration from the conditioned spaces into the attic via bypasses created by the penetrations for the recessed lighting fixtures. In damp and cold climates such as Minnesota, Wisconsin, etc. this significantly increases the potential for condensation forming on the roof framing and the underside of the roof substrate resulting in deterioration of the substrate and the growth of mold. This doesn’t mean that the same can’t occur in Colorado.

The electrician is probably correct in stating that the installation meets the requirements of the electrical code. However, it’s unlikely that either the builder or the insulation contractor understands building science, otherwise, all penetrations between the conditioned spaces and the attic spaces would have been properly sealed using appropriate materials.

You would be correct in identifying what you photographed as adverse conditions and recommending immediate action by a qualified insulation contractor for further evaluation and any necessary modifications or corrective measures.

Picture 1 makes me think there is a dropped soffit or other large air leak under the insulation that is not sealed.

Air tight canned lights have several different way they can be sealed. Some require a special reflector baffle that seals the light. Installing a standard baffle will not make it air tight. Some brands will have a gasket that fits between the drywall and the housing. If the installer is serious about making it air tight they will use fire rated caulk to seal the wire connection. Can lights do have a little heater in them that will pump the air out of the house is they are not well sealed.

I have read that the fire retardency of cellulose has not been degraded by repeated wetting. I would not worry about the insualtion. Though I do think that it is a sign of air leaks and mositure that has the potential to cause damage. Also it is a big energy penalty.

Since previous posts stated that the cans are not an issue let’s focus on the moisture bleeding through the energy envelope. Escaping air around can lights is a common problem even if they are newer and improved models. Air movement brings warm air into the cold attic along with vapor in winter. In the summer it allows cool air to enter the attic and condensation forms in the area. In either case moisture is the visible result. Proper sealing may help but unless the insulation is removed from the areas and the lights are able to be sealed completely (depending on the type) some air leaking will occur.

Mr Harper has my vote, He nailed it.

No one seals those cans, thats total vapor/ material reaction

I'd like to hear opinions on this recessed can cover. Esp. Mr. Harper.

EnergyFederation.org | Tenmat Recessed Light Cover

Fire Rated Light Covers

And that moisture is not from the house! Those are extremely proud and accurate squirrels! C'mon!

That first picture is especially interesting - would have been interesting to see IR of that portion of the attic floor on a cold day, w/ level and span adjusted to image insulation surface temperature, the areas around the lights a well, if they have been off long enough.

The boric acid leached from treated cellulose insulation can be quite corrosive to ferrous metals, BTW.