Water in finished Attic

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  #1  
Old 01-22-11, 11:14 AM
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Water in finished Attic

Hello everyone,

I'm in the final process of finishing one of the attics in a split level home. I've insulated between the ceiling joist and installed venting channels between the roof and the insulation for venting. This project has been going on for about a year. Last week I noticed the roof boards and joists in the other side of the home was damped and the nails were wet. Today I was insulating the knee wall drawers when I decided to stick my hand in the ceiling insulation, to my surprise I felt the insulation to be damped. I have invested several thousands of dollars in this project and is a room for my two older boys, anyone have an idea whats causing this. I have pictures that I will post if I can figure out how to.

Thanks in Advanced ,,

JOe
 
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Old 01-22-11, 11:29 AM
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How old is the roof? What is it made of? Is there a lot of snow on it? Has there been an unusual amount of rain? What temperature is it in the attic?
 
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Old 01-22-11, 11:36 AM
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Originally Posted by bish80 View Post
How old is the roof? What is it made of? Is there a lot of snow on it? Has there been an unusual amount of rain? What temperature is it in the attic?
The roof is less than 5 years old, there has been snow on the roof for some time since we've been getting hit in the northeast with snow. the temperature in the finished attic is 70f. I'm really worried about this issue. I have pictures that I can email since I cant post. Thank you

I was able to get some pics up, hopefully this works


ATTIC pictures by fajoza45 - Photobucket
 
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Old 01-22-11, 02:04 PM
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Warm moist air leaking into the cold air space is responsible. The same thing happens in a home that is under construction when you have fiberglass batts in the walls and ceiling, and you are heating the house with a propane heater during the winter months. With no solid poly vapor barrier to act as an air + moisture barrier, and no drywall up to act as a secondary air barrier, water vapor condenses on any object that is below the dew point. It can cause insulation to be wet, and if the object is below 32F it will cause ice and/or frost. Heat rising off of (what I assume is a IC ceiling light) is apparently melting frost above the insulation, causing it to wet the kraft facing in that spot. This is exactly the same situation that you have in your attic, except that instead of a propane heater supplying the heat and moisture, it's the heat that is naturally rising off of the house.

The insulation you have installed in the rafters is really counter productive, IMO. It's making the attic space warmer than usual, as if it were supposed to be conditioned space, which attics are not designed to be. Warm air holds more moisture than cold air does. So your RH is obviously higher in the attic now than it was before you put insulation in the rafters. The kraft facing is a vapor retarder, which really doesn't belong above the insulation in your ceiling joists (attic floor). If snow is blocking your ridge venting (on the roof), you have no ventilation. How is moisture in the attic supposed to escape when you have everything in the rafters blocked off? Attics need to ventilate. Where's the ventilation? Also the insulation in your ceiling joists (attic floor) appears inadequate and lumpy. Most USA areas recommend a minimum of r-38. (See link) Finished attics are almost always a bad idea. You can't expect an attic to perform like a conditioned space would.

If a person wanted to have a truly finished attic, you would first of all have larger rafters that could be insulated to > R38, there would be no insulation in the attic floor, and the VB would be against the bottom of the rafters. Not only that but ventilation would be provided by your HVAC. Warm air would be introduced through ventilation and cold air would return / be exchanged with fresh air. The ceiling would also be covered with drywall to act as a secondary air barrier. Foam and Kraft facing aren't allowed to be finished surfaces in "finished areas".
 
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Old 01-22-11, 02:38 PM
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Originally Posted by XSleeper View Post
Warm moist air leaking into the cold air space is responsible. The same thing happens in a home that is under construction when you have fiberglass batts in the walls and ceiling, and you are heating the house with a propane heater during the winter months. With no solid poly vapor barrier to act as an air + moisture barrier, and no drywall up to act as a secondary air barrier, water vapor condenses on any object that is below the dew point. It can cause insulation to be wet, and if the object is below 32F it will cause ice and/or frost. Heat rising off of (what I assume is a IC ceiling light) is apparently melting frost above the insulation, causing it to wet the kraft facing in that spot. This is exactly the same situation that you have in your attic, except that instead of a propane heater supplying the heat and moisture, it's the heat that is naturally rising off of the house.

The insulation you have installed in the rafters is really counter productive, IMO. It's making the attic space warmer than usual, as if it were supposed to be conditioned space, which attics are not designed to be. Warm air holds more moisture than cold air does. So your RH is obviously higher in the attic now than it was before you put insulation in the rafters. The kraft facing is a vapor retarder, which really doesn't belong above the insulation in your ceiling joists (attic floor). If snow is blocking your ridge venting (on the roof), you have no ventilation. How is moisture in the attic supposed to escape when you have everything in the rafters blocked off? Attics need to ventilate. Where's the ventilation? Also the insulation in your ceiling joists (attic floor) appears inadequate and lumpy. Most USA areas recommend a minimum of r-38. (See link) Finished attics are almost always a bad idea. You can't expect an attic to perform like a conditioned space would.

If a person wanted to have a truly finished attic, you would first of all have larger rafters that could be insulated to > R38, there would be no insulation in the attic floor, and the VB would be against the bottom of the rafters. Not only that but ventilation would be provided by your HVAC. Warm air would be introduced through ventilation and cold air would return / be exchanged with fresh air. The ceiling would also be covered with drywall to act as a secondary air barrier. Foam and Kraft facing aren't allowed to be finished surfaces in "finished areas".
Thank you so much for your reply..

The rafters in the other side of the attic are not insulated and I'm getting the same issues, but now after you explained it, I believe that it could be due to warmer air leaking over from the finished attic. There is a full access door that connect both sides and it stayed slightly opened most of the time. I just recently weather proofed the doors and caulked the in wall dressers.

As you can see in one of the pictures I installed that foam membrane in order to keep spacing between roof and insulation for ventilation. I'm assuming this wasn't enough. I have a mini split air/heat pump unit in the finished attic to supply heat and air.

What do you suggest I do. This room is really important as we only have three bedrooms in the house and our two boys love it up there. Taking down the insulation from the ceiling rafters that are not in the finished area.?


Any other suggestions is greatly appreciated. I posted another photo of the finished area.

ATTIC pictures by fajoza45 - Photobucket
 
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Old 01-22-11, 03:09 PM
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If it was me, I'd treat the unconditioned area of the attic as just that- unconditioned. That would mean removing the insulation from the rafters. It would mean ensuring that the knee walls, built-ins and doors are adequately insulated since the space on the opposite side of the wall will be cold. The colder that space can be, the better, provided it is adequately insulated from the rest of the house.

You may always have a problem with frost above the finished space, partly because of the possibility of an inadequate VB above the drywall, but primarily due to the fact that there is inadequate insulation in that space and the narrow ventilation space due to the rafters likely being too small to cram both into the same space.

As a second suggestion- and a costly one, I would recommend removing all fiberglass from the existing exposed knee walls & floor in the unfinished attic space and replace with R38 spray foam. It would provide superior insulation AND a vapor barrier to dramatically reduce the humidity in the attic (effectively isolating that attic space from the rest of the house) which should reduce the amount of frost that could ever potentially collect in the attic.

Another school of thought would suggest eliminating the ventilation space completely by using spray foam to completely fill the rafters everywhere so that the insulation is below the roof, not above the ceiling. I'm not completely sold on that idea though. In some ways, eliminating the space where condensation and frost takes place makes sense, but a hot roof can also be hard on the life of your shingles.

PS: I've noticed the mods prefer it if you hit "reply" instead of "quote" when quoting isn't absolutely necessary.
 

Last edited by XSleeper; 01-22-11 at 03:24 PM.
  #7  
Old 01-22-11, 03:37 PM
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I will start removing insulation as soon as possible. What about that wet insulation will that cause a problem ?
 
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Old 01-22-11, 04:04 PM
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It will not likely be a problem. If it was summer, it might be a different story. I'd suggest that as you remove the kraft faced insulation, you peel it off of the facing and lay it perpendicular to the floor joists (wet side up), to provide additional insulation for the attic floor. Unless you have other plans for it. It will eventually dry out on its own.
 
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Old 01-22-11, 04:42 PM
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Outstanding, I was just going to throw it away. I thought wet insulation would cause a problem . Thank you for your help. So all this is being cause by me not properly sealing that finished attic and having insulation on the side walls.. Thought I might have a leak somewhere on the roof...
 
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Old 01-22-11, 05:20 PM
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If there is a large area of wetness, in almost every rafter cavity, and there is moisture or frost on the bottom of the roof sheathing, I would say that it's just from the warm moist air from the house & attic hitting the colder snow covered roof and condensing.

I can't rule out a roof leak, especially if you have skylights. If the leak is ONLY beneath the skylights then I'd suspect that. But it sounded like you were generally finding wet insulation everywhere above the kneewall.

Wet insulation will cause a problem if it is enclosed, such as in a wall where fresh air can't get to it to dry it out. If you lay it out so it can dry it will be fine. You might need to flip it to aid the drying process. Kind of like raking hay. Oh wait- ur from Jersey. I guess they have hay in some parts of the state...
 
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Old 01-23-11, 06:54 AM
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No soffit vents or there covered over with insulation, no ridge vent, Ice dam caused from not enough insulation in the ceiling below. Roof that needs replacing or at least repairs.
With no ridge vent and soffit vents, then hot moist air gets traped and condenses on the sheathing.
We also have been doing something differant, after installing the insulation on the knee wall and the ceiling below we add a layer of Tyvek over that. It stops the air from coming in but allows the wall to vent.
 
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Old 01-23-11, 07:12 AM
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I'm going to remove the insulating in the rafters today. Every single rafter is wet on both sides, so I dont think is a leak. I dont see any frost on the inside but the sheathing is moist and the nails feel wet...

I didnt install Tyvek, but I do have a thick Ply of plastic behind the insulation of the knee wall...
 
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Old 01-23-11, 08:32 AM
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Joe suggests the Tyvek on the cold side of the fiberglass because if there is air movement (wind) it will reduce the effectiveness of your fiberglass. R-values are calculated based on a dead airspace. Tyvek would theoretically help in that regard. The poly is a VB and you were correct to put it on the warm side of the insulation.
 
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Old 01-23-11, 10:00 AM
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I couldn't see in the picture if you had them but I would add some roof vents as joecapiton mentioned. Your soffit vents will draw in dry outside air and the roof vents will allow the moist air to get out.
 
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Old 01-23-11, 10:14 AM
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Originally Posted by XSleeper View Post
If snow is blocking your ridge venting (on the roof), you have no ventilation.
I assumed there was continuous venting in EVERY bay, but that it's possibly blocked by snow. Joe hasn't commented on the ventilation issue, but I assumed that under all that kraft faced insulation in the rafters, he put continuous baffles in every rafter bay leading from the vented soffit to the continuously vented ridge.

Joe could clarify this if he takes a break from removing insulation.

Even if it is being vented properly, frost can still occur because of the close proximity of the warm ceiling to the cold roof.
 
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Old 01-23-11, 02:29 PM
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Baffles are installed on every single one. If it has insulation it has it. I went from soffit to ridge vent. Acutally at the top it levels out with the ceiling. But like I explained earlier, I have the same issue in the attic thats on the other side of the house. Wet and damped plywood.
 
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Old 01-23-11, 03:52 PM
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I think I've pictured everything correctly then. If your ridge vent is blocked by snow, you probably have humidity building up inside the attic since air can't exhaust. Some frost and condensation is probably normal, and would usually dry out when conditions permit it. But it could also indicate the lack of a continuous vapor barrier, with a lot of moisture coming up through gaps in the insulation, along the sides of the joists, around can lights electrical wiring, and so on. This is why I suggested spray foam on the floor and kneewall as a solution since it would provide a continuous vapor barrier.

It's probably not a good idea to get on the roof if it's icy, but the ridge vents need to be kept clear for them to work properly. Thats why I mentioned the ridge venting earlier.

I imagine that you will have less moisture on the sunny side of the roof, more moisture on the colder northern facing part of the roof.
 
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Old 01-23-11, 04:48 PM
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The ridge vent is clear of the snow. Snow is now covering from the middle of the roof down to the gutters. How do I insulate the light cans after they are installed.. ?
 
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Old 01-23-11, 07:33 PM
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Cans can be removed by taking out the three or four 1/4" hex head screws on the inside of the housing. The can can then be pushed up and allow access to the electrical box and a good portion of the attic through the 6" hole.
 
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Old 01-23-11, 08:08 PM
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Originally Posted by Tolyn Ironhand View Post
Cans can be removed by taking out the three or four 1/4" hex head screws on the inside of the housing. The can can then be pushed up and allow access to the electrical box and a good portion of the attic through the 6" hole.
I Installed the ones that are pushed in and held by clamps. I guess is for an already finished room. I'm just curious how I can insulate them, so I dont loose any heat through the lights..
 
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Old 01-24-11, 04:45 AM
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That was just recently discussed in this thread.

http://forum.doityourself.com/baseme...t=#post1816340
 
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Old 01-24-11, 08:56 AM
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Ok,, just took off insulation that was in the joist . Wow everything was frozen!!!! tons of drips coming down now. I notice drips down in my kitchen ceiling which is under that area of the attic. I guess the insulation was covering the soffits as well . What a mess, hopefully this will start alleviating the problem.
 
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