kenneth nelson
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| 11/04/2009 1:27 PM |
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I have condensation collecting under the surface of the Firestone TPO mebrane that is applied directly on the 12" & 8" SIP flat roof structure. The flat roof (with 1/4"/FT slope) is approximately 500 SF of a 3500 SF house that was completed 4 years ago. The Sip panels were sealed at the joints with 12" wide SIP tape furnished by the manufacturer as per thier recomendations. There is excesive moisture at the joints running off the meter scale with readings of about 50% in the panel centers. Humidity readings inside are in the 50 - 60% range. The roof has been inspected with no signs of leaks. What could be the cause and how can it be corrected?
Ken Nelson |
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cmkavala
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| 11/04/2009 1:34 PM |
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Kenneth;
your interior humidity is the high sde of normal,
1. What is the spline made of?
2. Was mastic used?
3. What is the area used for undr the flat area? |
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Chris Kavala
chris@southernsips dot com
1-877-321-SIPS |
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kenneth nelson
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| 11/05/2009 11:02 AM |
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Chris,
1. the 12" panels have double 2X12 splines and the 8" panels have foam and OSB splines
2. the mastic was supplied by the manufacture
3. one is a pantry and oil fired furnace room, the other is a walk-in closet
I was told by an inspection engineer hired to evaluate the problem that 50-60% is well within the normal range
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pdk
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| 11/05/2009 11:15 AM |
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50-60% is not within acceptable range in a tight home. With that high of moisture you will have lots of issues with mold, rotting window sills and even health issue eventually. Vent your baths, kitchen and of course the dryer. If you still have high humidity get a dehumidifier and connect it to a drain. It always best to get rid of the
humidity source first. (Some dishwashers give off tremendous moisture)
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cmkavala
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| 11/05/2009 2:48 PM |
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Posted By pdk on 11/05/2009 11:15 AM
50-60% is not within acceptable range in a tight home.
where do you get your info from?
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Chris Kavala
chris@southernsips dot com
1-877-321-SIPS |
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cmkavala
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| 11/05/2009 2:59 PM |
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Posted By kenneth nelson on 11/05/2009 11:02 AM
Chris,
1. the 12" panels have double 2X12 splines and the 8" panels have foam and OSB splines
2. the mastic was supplied by the manufacture
3. one is a pantry and oil fired furnace room, the other is a walk-in closet
I was told by an inspection engineer hired to evaluate the problem that 50-60% is well within the normal range
Kenneth;
pdk is off base and 50-60% is still OK if it gets much more above that it could be problematic, my SIPs home is 45 - 55% depending on the season
was the mastic supplied actually used?, It is why you really need to core especially@ a double 2x12 spline, if I had to guess sight unseen, I would say there is a good possibilty that some separation has occured in spline joint allowing moisture up thru.
Another possible - if there are any roof penetrations for dryer/range vents leaking at membrane, plumbing stacks not sealed well on under side would allow air to hit back side of membrane |
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Chris Kavala
chris@southernsips dot com
1-877-321-SIPS |
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jmagill
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| 11/05/2009 3:49 PM |
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| I am no expert but live in a SIP home. We need to keep the humidity below 40% in the winter of we get too much condensation. 30-35 is ideal for us in the winter. |
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cmkavala
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| 11/05/2009 4:01 PM |
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jmagill;
I should have added it depends on climate too. |
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Chris Kavala
chris@southernsips dot com
1-877-321-SIPS |
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cmkavala
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| 11/05/2009 4:06 PM |
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our interior sip home in the south is typically 50% summer, 45% winter, the only way it gets down to 35% is if we leave windows open in the winter.
but never ever had a mold issue reported in any of our homes with or with out ERVs |
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Chris Kavala
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pdk
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| 11/05/2009 5:26 PM |
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Sorry to say Chris but my first sip home with electric heat had mushrooms in one of the closets coming through the carpet. Nice, dark, damp and cool. No heat recovery system (not around yet). Since then my other homes have had no issues due to HRV and better moisture control. Much better technology today
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jmagill
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| 11/05/2009 5:44 PM |
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| I would say that these are all three rooms with very little air movement. Combine that with high humidity and that could be the cause. |
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cmkavala
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| 11/06/2009 6:17 AM |
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Posted By jmagill on 11/05/2009 5:44 PM
I would say that these are all three rooms with very little air movement. Combine that with high humidity and that could be the cause. That is the problem, and a reason to increase a HVAC air handler size ...... not for cooling, but for air volume.
my 2400 sq.ft. house could have been done with a 2 ton , but my HVAC contractor recommended a variable speed 2.5 for volume.
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Chris Kavala
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cmkavala
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| 11/06/2009 6:35 AM |
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Posted By pdk on 11/05/2009 5:26 PM
Sorry to say Chris but my first sip home with electric heat had mushrooms in one of the closets coming through the carpet. Nice, dark, damp and cool. No heat recovery system (not around yet). Since then my other homes have had no issues due to HRV and better moisture control. Much better technology today
forced air electric, base board or radiant?
does the closet back up to a bathroom?
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Chris Kavala
chris@southernsips dot com
1-877-321-SIPS |
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pdk
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| 11/06/2009 7:20 AM |
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| It was baseboard electric (oil radiant), closet was not backed to bathroom. I only had ceiling fans for air movement in all the main rooms with windows in baths for ventilation. This is in Michigan. |
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kenneth nelson
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| 11/06/2009 10:43 AM |
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Chris, There are no roof penatrations and the sealant/mastic was used along with the joint tape. If the membrane was leaking , I would assume that moisture would have shown up at the at the interior ceiling. There are lots of exhaust fans and wall intake vents. The house has hydronic hot water heating in the slab.
Ken |
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cmkavala
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| 11/06/2009 12:56 PM |
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Posted By kenneth nelson on 11/06/2009 10:43 AM
Chris, If the membrane was leaking , I would assume that moisture would have shown up at the at the interior ceiling.
Ken
I would have expected that 50% moisture content at the ceiling joints would have caused discoloration, what is the moisture content away fro the joints?
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Chris Kavala
chris@southernsips dot com
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jstelmack
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| 11/08/2009 10:09 AM |
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| Ken, Is it possible that there is air movement between the TPO membrane and top of the SIP panel? The thinking is that if there is air movement between those two surfaces condensation would be the result. Even if the condensation is minor there is no little drainage out. Over time it would accumulate. Do you know anyone with a thermal imaging camera? If not, check your area for a HERS Rater. Some of those guys either have one or have access to one. It might show varying temps along the surface (interior and exterior) of the roof. If so, you'll have clues where to focus the investigation. |
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davidqxo
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| 11/16/2009 5:57 PM |
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How did you discover the condensation problem?!
I fear we may be subject to the same problem. Our SIP panels were delivered just as our two year drought broke. We've had six weeks of heavy rains, with few dry days between. I'm concerned about getting our low slope roof adequately dried out before applying the TPO membrane.
The SIP seam tape that was originally applied to the underside of the SIPs all fell off due to excess moisture.
Our current plan, as soon as we can get the house sealed, is to run a dehumidifier to dry everything out before reapplying the tape, or perhaps spraying with closed cell foam instead.
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cmkavala
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| 11/16/2009 6:35 PM |
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| AH HA! that's how it happened, the roof was never dried out befor e the TPO was put down and now its trapped |
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Chris Kavala
chris@southernsips dot com
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John Hatfield
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| 11/18/2009 10:38 AM |
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| The problem may be more with the TPO than with the SIPS panels. TPO is a hard product to weld together correctly and seams may appear to be good on application and separate later. In addition if the TPO is not glued to the OSB top of the SIP it will have air flow through out the underside of the roof membrane and moisture from pipe penetrations maybe accumulating under the membrane. I would start by scouring the roof surface for problems and remember that a certain small amount of moisture can travel through the TPO if in a ponding conditions. Suggest that the roofing contractor return and probe each seam 100%. |
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