| Title | By | Posted On |
| sloped ceiling |
miller0723 |
5/3/2007 |
This is an image of a sloped ceiling. The ceiling is facing south and the sun is out. The Delta T is around 30f. There is solar loading but no signs of any holes on the inside or outside. The ceiling has r-19 with baffles in place. It has not rained in 4 days. There is no thermal bridging that i can see. Anyone with a good guess?
yourenergy@thermalconcepts.net |
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| Re:sloped ceiling |
Toolman |
5/7/2007 |
| What type of insulation! If it's blown-in, the hot spots might be areas where it has settled or is not as thick - fairly common for this type of insulation... |
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| Re:sloped ceiling |
thermalconcepts.net |
5/7/2007 |
Toolman wrote:
pe of insulation! If it's blown-in, the hot spots might be areas where it has settled or is not as thick - fairly common for this type of insulation... this has R-19 batt fiberglass w/kraft on upperside |
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| Re:sloped ceiling |
JNTOOLS |
5/8/2007 |
Without seeing visible images of the surrounding areas, it is difficult to give a definitive answer. A few educated guesses, the fiberglass batt insulation is not in contact with the gypsum in the areas that show the anomalies and there are air pockets. The air entering the soffit vents is sitting in these pockets and being heated. Strong winds can blow baffles out of place and cause the insulation to lose contact. Other rare possibilities could be the insulation was pieced together and you are seeing open seams.
J. Nachman
Longwave Inspection
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| Re:sloped ceiling |
Dan. M |
6/7/2007 |
miller0723 wrote: an image of a sloped ceiling. The ceiling is facing south and the sun is out. The Delta T is around 30f. There is solar loading but no signs of any holes on the inside or outside. The ceiling has r-19 with baffles in place. It has not rained in 4 days. There is no thermal bridging that i can see. Anyone with a good guess?
yourenergy@thermalconcepts.net Though it hasn't rained in 4 days, trapped moisture from a previous hard rain could have settled in these areas if there is a roof leak issue. Is there roof flashing above the hot spot areas? You mention that the sun is out - what kind of roof membrane is on the house? Could it be a standing seam roof. That may explain the vertical pattern of the hotspot as well as the spots being warmer than their surroundings in the "heat of day. It's a stretch but that's all I can gather from the data given. |
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| Re:sloped ceiling |
thermoman |
6/7/2007 |
| There is no information regarding winds velocity and direction. This would help to determine cause. Also without proding for moisture readings, inspection of same area at dusk and late evening would assist in determining causal mechanisms due to either convection or conduction. Without further information on wall/roof assembly, interpretation it is still a shot in the dark... (or should we say in the daytime). |
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| Re:sloped ceiling |
PKirk |
6/7/2007 |
| Is this a garage? In which case a car may have been idling for a while before the image was taken. What is the irregular orange circle in the bottom right of the image? |
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| Re:sloped ceiling |
thermalconcepts.net |
6/7/2007 |
PKirk wrote:
a garage? In which case a car may have been idling for a while before the image was taken. What is the irregular orange circle in the bottom right of the image? This is an image of a sloped roof. The wind direction is from the south at around 5 mph. This sloped roof is on a log home. this is the second floor. This home is called 1.5 stories because the sloped roof starts at 4 feet high on the second floor. The roof is made of asphalt shingles. There is no sigh of moisture intrusion. |
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| Re:sloped ceiling |
Gary Goodman |
6/8/2007 |
| It could be that the fiberglass is inconsistently installed allowing convective currents or reduced R-value. Was it hotter or colder outside because if it were hotter out you could have air entering the eaves and washing through the insulation |
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| Re:sloped ceiling |
LenMelso |
6/10/2007 |
Is it a vaulted ceiling where the wall is 8' high, or a kneewall that is around 4-5' high? If it is the latter, these rooms are usually constructed w/ "RiR" (Room in Roof) trusses, spaced 24" o.c. I've seen where insulation installers skimped and installed lengthwise seamed batts of scrap insulation rather than 24" wide batts. They installed tape to the seams, but in a staggered fashion w/ open areas, thus creating pockets of Delta T's. Last winter, I experienced something similar. I saw cold spots, and suspicion of water intrusion from the nearby skylights made me check w/ moisture meter. I got a positive reading, and the homeowner decided to remove a small portion of the drywall to check. It turned out to be two lenghtwise seamed pieces of insulation. The false positive was b/c the areas had small amounts of frozen condensate d/t the voided areas allowing higher temp shifts from day to night. (Scan was done around 9am)
I see hot spots like these when scanning new homes before drywall is installed and sometimes it's just a torn area in the kraft facing. Unless it is truly water intrusion (which I highly doubt), it's a minor anomaly and should be dismissed as such. |
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| Re:sloped ceiling |
Bob Kulakowski |
6/18/2007 |
I am drawn to the original statement of craft paper facing UP. This is not the proper installation of craftfaced insulation. The paper should face to the conditioned space.
Was a humidifier used in this room? The insulation may be saturated thus reducing its insulation properties... Just a thought. |
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| Re:sloped ceiling |
southface |
7/22/2007 |
JNTOOLS wrote:
seeing visible images of the surrounding areas, it is difficult to give a definitive answer. A few educated guesses, the fiberglass batt insulation is not in contact with the gypsum in the areas that show the anomalies and there are air pockets. The air entering the soffit vents is sitting in these pockets and being heated. Strong winds can blow baffles out of place and cause the insulation to lose contact. Other rare possibilities could be the insulation was pieced together and you are seeing open seams.
J. Nachman
Longwave Inspection
I agree. I've seen this many times and it is almost always where the batt insulation isn't in contact with the gypsum and it is showing at the venting. It takes a little bit of attention to apply this insulation properly. |
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