Thread: Attic Sheeting is Black in One Location

I have a section of attic (roof) plywood sheeting that is black. It is directly above the wood stove (fireplace insert) in the livingroom below. My first thought was that the chimney is cracked and allowing smoke into the attic. Upon closer inspection (there is no smoke smell), I think the problem is condensation. The chimney is on the exterior wall of the house, so there is no soffit vents on the exterior of the house at this location. To fix the problem, I think I need to improve the attic ventilation. The house has no ridge vent. It has two gable vents with an attic fan. Would adding a humidstat to the attic fan control help? I don't know the cfm rating of the attic fan, but would a larger fan possibly help? Any other ideas would be appreciated.

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My first thought is how much ceiling insulation do you have?

How about a picture of the area?? Pictures are worth more than a 1000 words as the old saying goes.....

Black is either heat or moisture.

so to speak...

I don't think I got the photos you requested to post, so here is a link to the photos.

Attic Photos pictures by BrentyBooBoo - Photobucket

There is 6-inches of attic insulation.

It appears to be mold growing there, due to a moisture problem, moist air from below leaking into that rafter bay and condensing on the cooler roof sheathing. Mould, which is everywhere, grows well in that environment as long as there is moisture.

If you pull the insulation away, you may find living room air is leaking into the attic in that location.

Originally Posted by Myron Amick

There is 6-inches of attic insulation.

Is there a vapor barrier installed below the insulation shown in the picture?

The backing on the insulation is the only type of vapor barrior below. Is it possible that this is from a roof leak that the former homeowners had and we just never noticed it until now?

Do you have a picture of how the chimney is flashed to the roof?

Another question is, "Is the moisture barrier facing towards the attic or the living space"? Of course, this will not make a difference in this case but is still important.

You should check the roofing nails for rust and loose condition...

Best

Ron

Similar problem

1 No Baffels add them to Venilate.
2 Remove the Insulation Stuffed in the Soffits make sure enough vents are there. ( Ownens corning has gret Information on 1 & 2 )
3 Clean the underlying structure with a biocide detergent like Ultra Clean
4 Apply a mold-inhibiting protective coating to prevent future growth. DepHyze Home

Your pix are kind of small, but they look exactly like some plywood under my roofing, which I traced back to a leak well upstream at the chimney flashing and patched. The plywood is dry now and still fairly sound, but I plan to replace it when I redo the roof soon.

After looking at the pics, you can see the bays next to the one in question also have the mildew growing at the eave edge. Doubt this is a leak. I think that Warren Scaman has nailed it.

Thanks for all the replies. My problem is that there are no soffits along the roof edge at this location. My brick chimney is here along the outside wall of the house. It is about 5 ft. wide. Is there some other way to ventilate this space?

Originally Posted by Myron Amick

Thanks for all the replies. My problem is that there are no soffits along the roof edge at this location. My brick chimney is here along the outside wall of the house. It is about 5 ft. wide. Is there some other way to ventilate this space?

No offense to the other posters, but you need to stop the source of moisture. Ventilation on either side of the chimney should be sufficient to keep air circulating in most cases.

Lets try this (for those that don't know how to post a photo, or view a hosted site's album beyond the thumbnail view).

Products of combustion include water vapor. You offer no photographic evidence of chimney or provide a photo from the outside as to orientation. Height of this chimney, perhaps it is dumping copious amounts of moisture into the attic. You claim no soffit vents (and perhaps have been covered) or suggest intake venting, yet make mention of mechanical fan. Perhaps negative pressures draw IN your chimney exhaust? If we are to believe that there is a chimney at the exterior end of these rafters/chords....then perhaps there is a breach in the flue at the ceiling or roof transition. Possibly no thermal break/space within and heat migrating could also be causing ice daming. Is there a cricket? Again all conjecture based solely upon the representations you made in your intitial post - because there is no evidence of a chimney in your photos. Perhaps you were describing a direct vent through the wall for your woodstove, pellet stove, or was it a gas appliance? As I read your posts, I'm gathering you have a five-foot wide brick fireplace and chimney on exteror eave wall - perhaps with factory insert or stove retrofit? From nailing pattern doesn't appear to have any sort of cricket to the chimney - could possibly be a breach in the flue, throat, firebox; prior chimney fire, or a bad flashing/icedam/water infilatration problem, simple bypass moisture from home pooring from wall cavity/ceiling cavity, etc. Either way it needs to be checked out. Number one would be clarifying your fireplace/stove/chimney situation and getting at least a Level II/2 inspection, and going from there. Depending on how long you've owned the home, a CLUE report might also be in order. Your Home Owner's Insurance agent should be able to help you in that regard, you might also check with the local fire department regarding history/response to your property. After diagnosing issues from the firebox out, you can then address flashing/roofing/cricket; masonry, and attic ventillation issues.

Looks like you have several issues, moisture being a primary one. At right sides of second and third photos see rusting roofing nail tips. The first photo appears to be looking down into a low height, low slope attic pocket towards a stuffed up (with insulation) eave with batt pink fiberglass insulation. Yes that appears to be colonized growth above, however lower down (2nd picture) appears may even be some sooting and carbonization. Perhaps there were at one time chutes installed and insulation of the underside of the roof deck/sheething which has since been removed, and insulation pulled off/fell. Vents may have been covered to hide prior soot and/or fire/water damage. Needs to be checked out further. Call in a chimney and fireplace professional for a minimum Level II/2 exploration. There may have been a prior fire event which lapped up the side wall. I do not see an exterior wall chimney anywhere in the photos in either "album" on your linked photobucket.