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Author Topic: Condensation on ceiling following new composition shingle roof  (Read 9082 times)

barbara

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Condensation on ceiling following new composition shingle roof
« on: September 15, 2009, 06:27:28 PM »

Several months ago I had a new roof put on.  A couple of months ago I noticed condensation on the sloped bedroom ceiling.  There is no plumbing above the ceiling at all, and no crawlspace.  There is a skylight, and the condensation appears every morning, evenly distributed about 2' above the skylight, as well as below it. During the day it always dries out. It does not appear on either side of the skylight, and again, it is evenly distributed about 2'x2' above and below.  There are no water spots at all on the ceiling.  I've called a plumber out to make sure there is no plumbing there, and I called a skylight company out to inspect the flashing around the skylight.  Again, no problems there.
 
I saved the wrapping from the roofing shingles.  It's a 30-year-composition shingle made by Timberline.  The specs call for a double layer of paper if the slope is less than 12/4.  I measured the slope and it is 12/2.  My contract with the roofer states that the requirements for a flat or low pitch roof are not applicable, so I'm thinking that only one layer of paper was put down.  He is coming out in two days to check out the roof.  I plan on having him pull up the shingles around the problem area, and if there aren't two layers of paper, I'll have him rip the entire section of roofing off, put down the two layers of paper, and then replace the entire area with new shingles as well.  Is this a reasonable demand?  The rest of my roof has a much greater slope (the bedroom was an addition added 30 years ago), so only the roofing over the addition would have to be replaced.  My husband died, so I am on my own here.  Am I doing the right thing?  Can you think of anything else other than the roof that might be causing the problem?  Oh, and I always use the shower in another part of the house, so the condensation isn't coming from the inside.  Also, the windows never have condensation on them in the morning.
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barbara

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Re: Condensation on ceiling following new composition shingle roof: added note
« Reply #1 on: September 15, 2009, 06:38:59 PM »

I forgot to add that I live less than a mile from the beach, so the humidity is always pretty high.  Thanks for your help.  :)
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CREIA Inspector

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Re: Condensation on ceiling following new composition shingle roof
« Reply #2 on: September 16, 2009, 08:28:55 AM »

Barbara, a couple of questions regarding clarification before our house detectives ponder your problem.  Are we talking about a vaulted ceiling where the sheetrock is applied to the bottom of the roof rafters (no attic space) and is the skylight installed in a perpendicular position across the roof rafter of parallel to them?
Thanks
 
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barbara

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Re: Condensation on ceiling following new composition shingle roof
« Reply #3 on: September 16, 2009, 09:52:02 AM »

Yes, the ceiling is vaulted and the drywall is nailed to the rafters.  The skylight is 4' long and 2' wide and runs parallel to the roof, not perpindicular.
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barbara

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Re: Condensation on ceiling following new roof installation
« Reply #4 on: September 16, 2009, 10:07:42 AM »

The roofer called and is now coming out in three hours to inspect the roof instead of two days from now.  Please help.  I'm sure he's counting on my ignorance.  One of his workers came out last week, walked on the roof, and then told me that the problem was from plumbing -- not roofing.  When I called out a plumber, he said that there was no logical reason for any pipes to have been placed between the rafters and the ceilings, and that if I had a drip problem, there would have been water spots on the ceiling,  the moisture wouldn't dry up during the day, and the leak most likely would have gotten worse over the past two months.
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Re: Condensation on ceiling following new roof installation
« Reply #5 on: September 16, 2009, 12:38:42 PM »

Barbara
Your additional information leads us to believe that the roof rafter bay in which the skylight is located is not insulated.  This could allow warm air accumulation during the day within the vacant rafter bay and then when cooled at night the result is usually condensation, which in turn permeates the ceiling gypsum board (sheetrock) ceiling.  The question is; was the roof sheathing removed during the re-roofing? If it was your roofer should have noticed the problem and corrected it.  However, if, during the removal of the old roof covering, the roof’s original sheathing was left in place then of course the roofer had no way of visually observing that problem during his re-roof.
The solution advised is removal of a section of shingles above and below the skylight and opening the rafter bay to confirm whether it is equipped with insulation.  We also suggest checking to confirm all of the vaulted rafter bays are vented.
 
PS: we don't understand your statement; "My contract with the roofer states that the requirements for a flat or low pitch roof are not applicable."  This makes no sense?
 
« Last Edit: September 17, 2009, 01:38:23 PM by Mike Schindler »
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barbara

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Re: Condensation on ceiling following new roof installation
« Reply #6 on: September 16, 2009, 01:05:39 PM »

The roofer wrote that the slope of the roof was greater than 4/12 so the requirement for two layers of felt was "Not Applicable."  In fact, the slope is 2/12.
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barbara

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Re: Condensation on ceiling following new roof installation
« Reply #7 on: September 16, 2009, 01:17:20 PM »

I forgot to answer your question about the sheathing.  The sheathing was not opened during the re-roofing.  Having said that, the skylight went in in 1991, and there was never a problem with condensation until the new roof went on.  Also, please let me know how important it is to have two layers of felt with a 2/12 slope.  Should I make him pull up that section of the roof and put down two layers?
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barbara

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Re: Re: Condensation on ceiling following new roof installation
« Reply #8 on: September 16, 2009, 03:53:59 PM »

The roofing contractor was just out.  His solution to the problem is to install an O'Haven Roof Vent in the problem area.  Am hoping this will resolve the condensation issue.  As for your question regarding the insulation beneath the sheathing, I assume that there is insulation there but am not absolutely sure.  I do know that this problem never ocurred before the new roof went on, and I have lived in my home for almost 25 years.
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barbara

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Re: Condensation on ceiling following new roof installation
« Reply #9 on: September 16, 2009, 04:36:58 PM »

Yesterday my neighbor went up on the roof with me to measure the pitch.  Today, right before the roofer came, I decided to double check it, so I went online to learn how to do it myself.  When measured CORRECTLY (aaaargh!) the pitch was just a tad under a 3/12.  Sorry for getting it wrong in my posts to you.  :( 
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Re: Condensation on ceiling following new roof installation
« Reply #10 on: September 16, 2009, 04:52:04 PM »

Barbara
First, was a re-roofing building permit obtained from the local building department and field inspections conducted by a local building inspector?
Second, the shingle and underlayment should be installed according to manufacturer’s installation instructions. 
If there are any manufacturers installation instructions lying around (one comes with each bundle of shingles) then I would save and read the instructions so written.
Third; there is always a chance that the skylight was not properly flashed during the re-roof.  Only removal of the shingles in that area will be able confirm that.

Here are the appropriate code sections from the 2007 California Building Code - Section 1507.
1507.2.2: Slope; Asphalt shingles shall only be used on roof slopes of two units vertical to 12 units horizontal. (17-percent slope)) or greater. For roof slopes from two units vertical in 12 units horizontal (17-percent slope) up to four units vertical to 12 units horizontal (33 percent-slope), double underlayment application is required in accordance with Section 1507.2.8.
1507.2.8: Underlayment Application; For roof slopes from two units vertical in 12 units horizontal (17-percent-slope) and up to four units vertical in 12 units horizontal (33-percent-slope) , underlayment shall be two layers applied in the following manner.  Apply a minimum of 19-inch wide strip of underlayment felt parallel starting, fastened sufficiently to hold in place.  Starting at the eave, apply 36-inch wide sheets of underlayment overlapping successive sheets 19 inches, by fastened sufficiently to hold in place.  Distortions in the underlayment shall not interfere with the ability of the shingles to seal.
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barbara

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Re: Condensation on ceiling following new roof installation
« Reply #11 on: September 17, 2009, 06:44:07 AM »

Yes, I obtained a permit (City of Dana Point) for the new roof.
 
The roofing contractor checked the flashing around the skylight, which I witnessed, and no problems were found.  I did save the wrapping from Timberline and I showed him the listed requirement for two layers of felt when the pitch is between 2/12-4/12.  My pitch is 3/12.  He said that a double layer of felt is suggested by Timberline, but that it is not required.  When I asked him about Dana Point's Building Codes, he told me that the double layer of felt is only required for pitches <2/12.  Do I have the right to have him rip off the roof and do it correctly?  Do you consider it to be a serious problem having only the one layer of felt?
 
Thanks so much for the time you're spending with me.
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Re: Condensation on ceiling following new composition shingle roof
« Reply #12 on: September 17, 2009, 04:20:47 PM »

Barbara,
I am somewhat puzzled why you personally obtained the building permit for your new roof instead of the roofing contractor? Home owners should always make sure their contractor pulls the permit as they have to prove to the authority having jurisdiction (city/county building department) that they have a current state license for whatever trade they’re practicing and maintaining an up-to-date Workman’s Compensation Insurance policy.  Contractors who ask the home owner to get the permit are often unlicensed and in the building industry referred to as “Gypsy Roofers.”

As far as your roofer saying that the manufacturer’s installation instructions regarding a two-ply underlayment is only a suggestion is simply not accurate.  To begin with manufacturer’s installation instructions trump code and more importantly if they’re not followed to the letter the manufacturer’s warranty can be and is often voided.  Whether you accept your roofer's job is your decision alone, but quite frankly I wouldn't.  Why not speak to your local building official for his/her take and then if need be consult an attorney who specializes in construction defects.
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barbara

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Re: Condensation on ceiling following new composition shingle roof
« Reply #13 on: September 17, 2009, 07:50:57 PM »

The contractor pulled the permit.  Sorry for the confusion. 
 
I spoke with the head of Dana Point's Building Department today about the underlayment.  He told me that because the contractor used  a 30lb underlayment, as opposed to two 15 lb layers, the City wouldn't have an issue with it.  He told me that two layers at 15lbs probably would have been better, but that the 30lb should suffice with a 3/12 pitch.
 
On Saturday the roofer is installing the new vent in the problem area.  He said if it fails to correct the condensation problem, he'll tear off the roof if need be.
time will tell....
 
 
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barbara

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Had another thought on the ceiling condensation problem....
« Reply #14 on: September 18, 2009, 09:04:10 AM »

I was awake half the night (again!) trying to figure out the condensation problem and came up with a new theory.  Before the new roof went on, I had a double layer of roofing that the guys had to strip off.  Also, about four months ago, I removed several very tall shrubs that shaded the roof (the roof has a western exposure).  Is it possible that, along with the shade that the shrubs provided, the previous double layers of shingles provided extra insulation from the heat, which in turn decreased the heat build-up in the cathedral ceiling?  I just went back up on the roof this morning, and was shocked to find that almost the entire roof over my bedroom is wet, even though I'm only seeing the ceiling sweat in a small area of my bedroom.  Fortunately the rest of my house has an attic, so the problem is only ocurring over the bedroom.  The roofer is coming out tomorrow to put a vent over the area where I'm seeing the ceiling sweat.  If it works, should I consider having him install a couple more in the roof? 
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