Replies

1. 
   DanH | Apr 26, 2012 09:09am | #1

   I would look for some moisture source (ways for house air to get into the space) in the area where you had trouble -- several poorly sealed penetrations, a leak in a heating duct, etc.

2. 
   florida | Apr 26, 2012 10:40am | #2

   That usually indicates not enough insulation and a faulty vapor barrier. Warm air is getting into the attic and condensing on the cold north side. You might be better off sealing your roof with foam instead of your attic.

3. 
   tobydouglas | Apr 30, 2012 04:52am | #3

   black stain dark side

   hey Joe,

   Well  the problem is condensation for you.  The replies to your post are quite accurate (I skimmed over them).  The approach you should use is this:  The roof is a system.  To elimianate the black stain you have to ventilate the roof period.  I admire the fact you want to increase the level of insulation in the roof, but the most effect you could have on your building envelope would be to look very, very, very, very closely at your windows and doors.  You'll get more cost recovery with your energy conscious efforts here. 

   Since you insulated your roof to a nicer level.  Please look closely at the ventilation of your roof.  (I live in snow country where lots of people have not provided for the ventilation of their roofs).  You can detect the problem from the street with the icicles formed at the horizontal eaves of the roofs.  Some of the icicles here are the size of volkswagons.  Now your particular situation is hopefully a little less severe, yet that black mold is the early indicators of what will eventually become a real problem with a rotten roof structure, a very expensive repair.  I can't draw you a diagram yet, so in words think of the solution to the problem as a path for moisture laden air that is headed towards your attic to escape:  start on the warm side of the building envelope,  move through the ceiling/wall finishes to the vapor barrier (lots of things are vapor barriers:  paint, plywood adhesive, plastic sheeting)  that needs to be intact without many holes to reduce the amount of moisture that can migrate into the roof, next there is the insulation (hopefully a nice leve, l your original roof was not really all that bad),  then you need a good blanket of air space (this equalizes the temperatureof the "roof covering" that actually separates the moisture that accumulates from above from entering the roof system.  If you simply do all this nicely, well no more condensation inside the roof system.  Basically:  continuous vapor barrier, hopefully some insulation, adequate ventilation, and a nice roof covering then problem solved.

   Douglas B Bockman,

1. 
   user-1125857 | Apr 30, 2012 08:29pm | #4

   black stain

   Thank you for taking the time to answer my question.I am still surprised that the south side of my roof is good but the north side is such a mess.Even with the rafter vents,ridge vent and soffit vents working,I guess a vapor barrier is the fix for this issue.There were plans to finish the attic space that just were put off too long.I will be conditioning the air space and finishing it with sheetrock and hoping this will be the remedy.

1. 
   Norman | May 01, 2012 02:42pm | #5

   R U sure that will help?

   As I read the posts, it has been suggested that interior moisture is entering the attic through the attic floor and then condensing on the cold attic surfaces.

   If so, drywalling the attic is only going to grow mold on drywall.

   I think you need to seal the attic floor first.

4. 
   Clewless1 | May 09, 2012 09:29am | #6

   Key to good attic insulation ... will be sealing air leaks to the attic from inside the house. Wire, pipe, and other penetrations (e.g. recessed lights!!!) all can contribute to problems in the attic. It's not the most fun job ... but take care of that aspect prior to insulation.