Attic moisture problem

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  #1  
Old 03-03-19, 07:53 PM
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Attic moisture problem

In 2015 I had the attic encapsulated by a mold remediation company due to mold on the sheathing. They mentioned insulation was stuffed in the soffits and that caused lack of ventilation. They installed baffles during the encapsulation. I have cold spots/ stains on some spots of my outter ceilings due to lack of insulation in tough to reach spots. I hadnt noticed any new mold since the encapsulation was done until this winter. In may 2018 I had the roof torn off and replaced. After looking in the attic about a month ago, I noticed the new roof nails are rusted. Also, Some peices of wood look wet/mold but only in this spot [I've enclosed a pic] its strange to me that this is only confined to this area. I had a ridge vent on the old roof and another one on the new roof. What would be causing this color discoloration in just this area after 4 years and a new roof?

It is a ranch style home. It is pretty well under insulated. Although costly, i would like to get the attic sprayfoamed to seal any leaks. I've seen videos where they sprayfoam the sheathing AND the floor. Which is correct?

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  #2  
Old 03-03-19, 08:11 PM
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Your car gets frost on it every morning just from sitting outside. It's no different in your attic... the difference is that you have moisture and heat loss from the house that is present in the attic. Things will get frosty up there from time to time and that is pretty normal.

No amount of ventilation will prevent warm moist air from condensing on a cold surface (your roof decking). Painting over the mold probably looks really nice and it hides a lot of stains. But the mold will grow back if the conditions are right. At some point in time, the conditions will be ripe for it to come back. People are just just hyper sensitive to mold nowadays and all alarms go off if any is detected. Up to you if you want to spend your money to fight it now or later. Killing mold is beside the point since it grows back whenever it pleases (whenever conditions are right for it).

The nice thing about painting it all white is that now it will look dramatic and get your attention when it gets moldy. One thing you could check is to fold back the insulation below that area and see if there is someplace on the attic floor that is not air sealed. Could be a bath fan or holes the electrician drilled or who knows. Looks like a big lump in the insulation right below it, so if a lot of warm moist air is escaping from that spot, it's adding to the condensation and frost particularly in that one spot. Check it out.

Any penetrations through the ceiling (attic floor) need to be sealed with spray foam. Warm air should not have a clear path to get in a cold attic.
 
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Old 03-03-19, 08:21 PM
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Thank you for the response. I definitely plan on looking for any places that are not air sealed and taking care of them. I am in Buffalo NY, so we get pretty cold in the winter months. I plan on beefing up the amount of insulation in the attic, as most parts do not go past the joists. Would you reccomend adding batts or blown in?
 
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Old 03-03-19, 08:53 PM
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Blow in is better because it leaves no voids. Just be sure your chutes are extended well above the insulation and that the top plate perimeter above the soffit / under the chute is stuffed before blowing it in. If the attic was empty, about 16" will get you up to R-49.
 
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Old 03-03-19, 09:01 PM
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Does it make a difference if the insulation that's "stuffed" between the baffle and top plate has vapor barrier on it? I would assume that air sealing and bringing the insulation up to R49 should stop the mold problems?
 
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Old 03-03-19, 09:23 PM
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No. Whats stuffed under the top plate doesn't really matter.

The general thinking for most climates in the US is that the latex paint (Class III vapor retarder) on your ceiling is the only vapor retarder you need. Ventilation takes care of the rest. That assumes all penetrations have been air sealed.

However in cold climates, the extreme in temperatures calls for more protection from vapor transmission. So in Zones 6 & 7, a Class I or II vapor retarder is recommended in ventilated attics. (See Table 2, point #10.)
 
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Old 03-04-19, 04:32 AM
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As X has said, air sealing and ventilation are key to eliminating the moisture that is feeding the mold. A couple of points:
1. Insulation does better when neat, no gaps or air paths to transport heat from the ceiling below to the vented space above.
2. The current baffles should be full width. Their function is to remove any heat and/or moisture at the bottom surface of the roof. leaving the few inches on each side fails to do that properly. I also see one smaller rafter space with no baffle, all need baffles.
3. I like site built baffles especially since you are going back to redo what is there.

I'll add a link on air sealing as it is one of the best areas to save energy.
https://www.energystar.gov/ia/partne...ide_062507.pdf

Bud
 
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Old 03-04-19, 08:57 AM
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Thank you for the replies. Getting into the areas to install the baffles is somewhat difficult. I was thinking of removing the soffits to gain better access. Would this be more of a hassle? Also, there are not baffles in every space. Are there baffles that can be cut to size?
 
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Old 03-04-19, 09:20 AM
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Ideally a baffle will have a flap that extends down to block the incoming air from hitting the end of the insulation, called wind washing. Adding that feature would be difficult from above unless all insulation is removed and then still tight.

If you vinyl soffits when warm they are easy to remove and replace. Actually easier for me as I work off of staging. From a ladder it would be slower and lots of exercise.

On my house there was 4' of sloped roof in the back so no way to address baffles from inside and I had the eaves apart extending them for more overhang. Mt approach was to slide a piece of 1" rigid up between the roof and the insulation, then I added a 1" thick strip of same foam on each side. Tight fit so I slit a piece of " pine about 1.25" wide up one side at a time. I put a handle on that board and rotated it to the 1.25 dimension. Slid the spacer in and extracted the wood. Dabbed some adhesive on the end I could see and repeated for the other side.

Google building your own ventilation baffles.
This is one article:
https://www.greenbuildingadvisor.com...fles-for-roofs

Bud
 
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Old 03-04-19, 09:44 AM
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I appreciate all the info Bud! My soffits are aluminum, not sure if removing them will bend them. I looked at the links you've sent, I see home depot/lowes sell baffles with flaps at the bottom. My last question is about sprayfoam insulation. I know it it much more costly, but if I were to remove all of the current attic insulation and have it spray foamed would there be any advantages or disadvantages of doing so?
 
  #11  
Old 03-04-19, 10:03 AM
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Your climate region would dictate how much spray foam would be needed but usually a minimum of 6 or 7 inches. That requires at least two applications, possibly 3. Applying too much creates curing problems and off gassing. Big note, I'm not a pro on spray foam.

Solve the source of the moisture first as that process can make a mess of your insulation. Then review how to repair or replace the insulation

Note, check out Roxul, much neater with a higher r-value.

Bud
 
  #12  
Old 03-04-19, 11:06 AM
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My plan is to first air seal and try to get baffles in every rafter. If I buy the type of styrofoam baffles I currently have, but get wider ones, and stuff insulation under them on the top plate of wall, will this be okay? How far past the wall plate should the baffle extend? In some areas of my home, I have cold spots on the ceiling edges causing staining which I assume is from no/low insulation in those areas. Is this because of the top plate not being insulated? Or the area before the top plate?
 
  #13  
Old 03-04-19, 11:20 AM
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"If I buy the type of styrofoam baffles I currently have, but get wider ones, and stuff insulation under them on the top plate of wall, will this be okay?"
That is a common approach.
"How far past the wall plate should the baffle extend?"
Just far enough so the insulation isn't blocking it.
"
In some areas of my home, I have cold spots on the ceiling edges causing staining which I assume is from no/low insulation in those areas. Is this because of the top plate not being insulated? Or the area before the top plate?"
Outside wall, air flow, and too little insulation make that area cold. The staining can be from condensation making the drywall damp and attracting dust. I have a picture of that happening where a piece of insulation was left out. New construction techniques specifically address that top plate area but retrofitting an existing home is difficult.

Bud
 
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Old 03-04-19, 04:10 PM
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I appreciate you taking the time to help me with this. After being up in the attic and crawling around I feel that taking the soffits off are the best bet.. I have 20 year aluminum soffit and gutters that are in good shape. Are the soffits typically nailed or screw in? Or just sit in the plastic/vinyl channels? If I actually have to remove the gutters, I may try and see if I can find a company that would do that and reinstall them for me.
 
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Old 03-04-19, 04:21 PM
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I don't know of any reason why you would need to remove your soffit or gutters. Your soffit should already be perforated (vented).

To work in the attic more easily, put down a few boards to work on.
 
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Old 03-04-19, 04:31 PM
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The reason I mentioned possibly removing them, is to gain access to where I have to install the baffles. It is a pretty low tight spot.
 
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Old 03-04-19, 05:07 PM
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I can see why you might think that is best... but its not. Your sections of baffle will probably be 4 feet long... your arms will reach at least 2 feet... so you don't need to be clear down to the end where its tight to get the baffles in. You will probably be 5 feet away most of the time. The baffle only needs to extend to the outside edge of the top plate... not way out into the soffit. Plus, due to the angle of the baffle and the top plate, the insulation you tuck under them has to be done from the inside of the attic, not the outside. And the baffles need to be stapled to the roof... also done from inside the attic... can't do that from the outside. Staple as far as you can possibly reach... that's good enough.

The worst part is insulating... but you will learn how to cut a piece and poke it under the baffle with a stick. It's not really that tough. But like I said it is nice to have some boards to work off of. Several pieces of 2' x 4' x 3/4" plywood work nicely if you can fit something that size up there.

Don't want you removing soffit and gutters for nothing... that's not how it's done.
 
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Old 03-04-19, 05:19 PM
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After reading you're response.. you're right. Thanks for mentioning all those points!
 
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Old 03-04-19, 05:24 PM
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Yes, we sometimes know what we're talking about. LOL
 
  #20  
Old 03-06-19, 01:27 PM
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Good afternoon,
I went up in my attic today and did some measuring. The space between rafters is 14 inches, and I currently have 12 inch baffles. I will be buying and installing 14 inch baffles this weekend.
As for stuffing the insulation under the baffle, couldn't I just put the batt fiberglass insulation back up against it instead of cutting a small peice and stuffing it in there?
- Also, I plan on removing the pink bagged top layer of insulation as seen in the picture above before blowing new insulation. That will leave me with the original fiberglass batts. I noticed that there appears to be two layers of fiberglass insulation kinda mushed together. It looks like the top layer has a vapor barrier on it as well as the bottom layer which I know it shouldn't have that. Being as old as it is, the paper just crumbles when i touch it. Should I remove the top layer of fiberglass insulation that has the vapor barrier on it and discard it? Or would it be okay to leave it? I know there should only be a vapor barrier facing the living space, but clearly whoever put this extra insulation over that didnt know that lol
 
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Old 03-06-19, 01:52 PM
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The reason you stuff insulation under is so that the top plate is insulated... and it pushes the baffle up right where you may not be able to reach it and staple it. No insulation over the top plate = more heat loss. Cold air should not be allowed to penetrate to the inside edge of the top plate... if it does you will have a cold ceiling perimeter, and that leads to mold on the ceiling perimeter of outside walls.
 
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