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Discussion Starter · #1 · (Edited)
We found a corner of drywall in our 2nd floor master bedroom where paint was bubbling from the ceiling (the popcorn texture is bubbling away from the sheet rock) and the where the two walls meet at the corner there is a faded area sloping in a V shape toward where the 2 walls meet.

We went up in the attic and noticed a water stain on the rafter above where the damage is located. The water stain went about two to three feet the length of the rafter and only about half the width of the rafter.

We also saw frosting on the decking right next to the rafter – which followed the length of the rafter for about two to three feet. The decking was not covered in frost – the frost is directly next to the rafter about one inch in diameter and three feet in length (along rafter).

I have had two contractors come look at the issue.

Contractor A indicated the fact that I have two vent types in this attic (turbine and static box vent) is causing a ventilation issue which produces moisture in the attic which turns to frost in that location. I have soffit vent baffles every other rafter - but Contractor A indicated the air from those is not being ventilated out the top of the roof properly because I have turbine vents and box vents right next to each other (two of each on the 2nd floor attic). They are within a few feet of each other...

Contractor A thought the roof has 5 to 7 years of life left. He has been in the business for over 20 years.

Contractor B indicated he thinks the shingles in that area are a little loose and need to be resealed down. He thought the roof needs replaced soon. He has been in the business less than 5 years.

I also have a sewer stack that needs a new boot or a rain cover placed over it because the top portion of the current boot is cracked. The sewer stack is below the area where frost is created next to the rafter on the decking.

Both contractors indicated the sewer stack boot needs replaced. Also the vents need to be replaced with box vents because of age of all vents.

The whirly bird and box vents are very close to the area where frost is created.

Will having turbine (whirly bird) and box (static vents) on the same roof cause a ventilation issue?

I want to replace all the vents with box static vents (the current vents are all old (whirly bird and cheap plastic box vents)).


EDIT:
I forgot to mention there are two bathrooms with showers on the second floor - both have their exhaust only going into the attic - one's vent hose is laying on all the blown in insulation (far >20-30 feet from frost rafter) the other has the vent hose hanging right next to the static box vent about 10-15 feet from where frost is occurring.

The frost isn't super close to either exhaust fan ventilation hose though. The attic access door is also a pretty good distance (10-15 feet) from the frost site.
 

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First thing is to get those bathroom vents piped outside so you are not dumping all that excess moisture into the attic space. It is a code requirement.

That may solve your moisture problem.

Contractor A is correct that turbine vents located too close to natural draft vents can reduce attic ventilation. If you pull air in the natural draft vents and eject it thru the turbine vents, you are extremely limiting, or eliminating the air intake flow thru the soffit vents.
 

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Has the attic ever been air sealed?
No one knows where you are and there's no pictures of the roof, so where going to have to guess on some issues that may be causing it but here's a guide to what the minimum amounts of insulation there should be.
https://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table
They sell a simple to install slip on boot to reseal that vent stack. If the shingles are in that bad a shape as you say it's going to be a mess trying to replace the whole thing.
https://www.zoro.com/oatey-roof-fla...JKGUsNxOZ_SJF33qEN1yuBoCTrPw_wcB&gclsrc=aw.ds
In most cases when replacing the roof I use ridge vents, then the whole roof gets vented.
Is your insulation blocking the soffit vents?
 

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Discussion Starter · #4 · (Edited)
Here is the picture of the frost in the attic - we have soffit baffles between ever other rafter pair - they are black plastic.

I will take some more pics when I get home.

You can see lots of insulation - there is seamless vinyl siding with perforation for soffit and I have those baffles in the attic. I purchased this home June 2015 in Iowa.

-- The frost might be a little hard to see but it's to the right of the first rafter in the middle there - third from the right.

Also you can see dark color on part of the rafter (top portion) where the moisture runs when it thaws.

Has attic been air sealed?
There are no leaks that I am aware of. We have an air tight attic access door which I pull faced back insulation over when we are not looking inside the attic. Just one attic access door for each attic (1st and 2nd floo r attics on this split level)
 

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Discussion Starter · #5 · (Edited)
First thing is to get those bathroom vents piped outside so you are not dumping all that excess moisture into the attic space. It is a code requirement.

That may solve your moisture problem.

Contractor A is correct that turbine vents located too close to natural draft vents can reduce attic ventilation. If you pull air in the natural draft vents and eject it thru the turbine vents, you are extremely limiting, or eliminating the air intake flow thru the soffit vents.
Should I install a roof vent or soffit vent to pipe the bathroom exhaust out?

One of the bathrooms is close to an exterior wall where I could duct the vent out. The other is kind of in the middle of the floor plan and would need 15-20 feet of hose to pipe out the wall.

Would it be okay to have a long exhaust duct like that to the wall or should i go directly above the fan and out the roof?
 

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You bought it in 2015, but how old is the house?

I'll be repeating other post here but for emphasis.
#1 would be to direct those bath fans to the outside.
#2 would be to verify the soffit venting and add baffles to every rafter space. The existing high vents are all exhaust vents and probably provide sufficient vent area, TBD. It is the low vents and baffles that need to be upgraded. (along with relocating the fan exhaust)
#3 what is the size of the house?
#4 can you provide a picture or two of the outside and those soffit vents?

Bud
 

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Discussion Starter · #7 · (Edited)
The house was built in 1980. It is 2000 square feet - split level. Frost issue is only on second level.

Here is my house
http://web.assess.co.polk.ia.us/cgi-bin/web/tt/infoqry.cgi?tt=card/card&dp=18100800054000


I will take some photos outside and of the baffles and outside soffit when I get home.

What method do you use of crawling around in the attic when blown in insulation exists to the extent I have it ?

Should I get some ply wood to place on top of ceiling joists in attic so I'm not placing a foot on each joist ? (Not real comfy) and hard to get close to over hang to view baffle vent source where air comes from soffit.
 

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LOL, if that is as deep as it looks there are few options for crawling around. I would plan for the access needed to install whatever you decide for venting of those bathrooms. Then rake the insulation away to where you can add some plywood or other support for walking around. That should also get you close enough to the soffit area for any inspections needed.

Baffles serve more than a path to get air from the soffits to the attic space, they allow cooling and moisture removal from the bottom of the roof deck, thus they should be installed in every channel. Retrofitting them at this point gives one pause. If you are near a rafter bay where you can add one, do so, but disturbing more insulation should wait to see if the exhaust redo solves the problem.

My preference for deep attic insulation and access is a 2x6 or other on edge perpendicular to those joists with plywood on top. Don't cover the entire attic as it creates a new condensation plane, but a couple of feet wide path is not a concern and really helps with getting around. Could be something to add to the areas in the directions you will be working.

I also looked at your roof from above and your 4 vents up there look properly spaced. It is a longer explanation, but different high vents do not reduce soffit venting. The air flow through those soffits is determined by the pressure across them and they do not care where that air exits, as long as it does.

Bud
 

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Discussion Starter · #10 ·
More images
Left side of roof is west facing and right side is east facing - west facing has weird discoloration around shingle edges..

You can see weird dark shadow above sewer stack and below whirlybird vent which is general area where I see frost in attic.

The fifth photo is the east side shingle and the sixth photo is the west side roof shingle (two pics before soffit pictures)

The west side of roof has chimney
 

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Shingles where install wrong around the waste stacks.
No cricket above that chimney.
I still stick with loosing all those useless vents and install a ridge vent.
Shingles installed wrong but should not be causing the leak.
 

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How old is the roof, it does seem to be showing its age? New shingles would definitely be an opportunity for removing the old vents and adding a ridge vent as Joe suggests.

Those soffit vents look fine from the outside as long as the space above them is not filled with insulation and each rafter bay has a clear air path below the bottom of the roof. Also, were the vinyl soffits installed over an existing plywood soffit that may or may not have vent openings?

Bud
 

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Discussion Starter · #13 ·
not sure on age of roof - contractor A thought 7 or so years of life left. Contractor b said five or so.

Seller did not indicate age of roof.

I was planning to replace all vents with metal box vents - have no interest in ridge after researching
 

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Discussion Starter · #14 ·
I need to get up there and move insulation to see the baffle and soffit vent in over hang.

Here are some images of a baffle and the area where frost was shown (none today)

The decking doesn't look wet at all... Just the right side of rafter the left side doesn't have dark discoloration.

The last rafter pic is of the left side of rafter where frost appeared.

Last pic is ceiling which got my attention to this whole thing.
 

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Ug!! That doesn't really look like a condensation issue. I've seen considerable condensation problems and they usually form on the underside of the sheathing, not tight in the corner between the rafter and the decking. my thinking is a leak from above. BUT that should also be apparent during warmer weather and related to rain and wind. Condensation is always a cold weather issue. Frost on the nails is however definitely condensation from humid air inside. Just a strange location along those rafters.

As for the baffles, that was part of the UG! Those look like 12" baffles in a 22.5" rafter cavity. That may allow some air to reach the attic, but does little to cool the roof deck and little to keep the insulation out of the soffits. When you get down there, check to see if they stuffed batt insulation near the bottom of the cavity to block the insulation.

Bud
 

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You may also be able to rent an IR camera for a day and Doug is correct, they are great at spotting moisture issues. You would probably want to inspect a day after a rain or warm spell to be able to check from outside as well.

Bud
 

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When any moisture evaporates it cools that area and the IR camera is extremely sensitive to any temperature difference.

The hose trick will work if there is a large enough hole, but what you are seeing is a very slow issue, be it a leak of some form of condensation. If the problem were dripping water you would have more indications inside.

One of the key points I mentioned before is, condensation issues go away when the weather warms up, but leaks from rain do not.

Bud
 
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