Porch ceiling frost and ice

8 years ago

Happy New Year!

I have a frustrated frost issue on my porch ceiling. My house is completed on Oct, 2017.

See pic 2 , My main entry porch roof is big triangle shape, it has quite big cavity space inside like attic.

First time I discovered the issue was a couple month ago when winter started, I noticed on the warm day, the ceiling closing to Den window area dripping water. I reported to builder and they sprayed insulation foam at highlighted in yellow area (see pic 1) . Around Christmas time, -40 °C cold snap hitted Alberta and I noticed frost on the ceiling again (see pic 3), builder opened soffits and discovered that inside cavity, a lot of frost, and ice built up (pic 4). Today is very warm my whole porch ceiling dripping water like crazy.

My builder told me that need a vent on the roof to help warm air escape. I am trying to figure where the warm air coming from. From the construction time the photos I took I have noticed that a heating duct pipe when through (see pic 1 red line ), I measured the temperature (see pic3 in red circle area) last week is + 4 °C, at that time, surrounding air temperature is -14 °C. apparently there must be some heat loses and escaped into porch attic cavity. condensation water built up to make frost and ice in the night time, at warm day time, ice melted, water dripping down.

My question are:

If just heat escapes into porch cavity, why so much moisture. The heat loses from heating duct pipe will not carry any moisture, just radiate warm air emitted into porach cavity, it should not cause any ice or frost formation, where is moisture coming from.

Will adding ventilation vent on top of roof help solve frost issue?

Is any other possible issue cause this problem?

Pic 1

Pic 2

Pic 3

Pic 4

Featured Answer

klem1

8 years ago

last modified: 8 years ago

While lots of ventilation might reduce amount of condensation,that doesn't cure the underlying problem. The bad news is that's the worst I've seen. The good news is that since it's so bad it will be easier to find the source of warm air. My advice is to write down as best you can recall,all conversation with builder and include documents,texts and pictures. Put the builder on notice he has 10 days to bring in an outside specialist (preferably of your choosing) at his expense to locate the source of warm air. If builder refuse's an outside specialist,I would hire a specialict and sue the builder. Possible specialists are utility company energy auditors and energy raters. If you insist on having people guess at this on the net,my guess's are laundry dryer,one huge or several leaks in heating ducts,malfunctioning whole house humidifier,1 huge or several air exchanges between living area and attic. There are tests to find this,it's insanely foolish to dink around guessing at it.

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Comments (7)

PRO
GN Builders L.L.C
8 years ago
last modified: 8 years ago
When warm air which entering that space is cooled sufficiently it can reach 100% humidity. The air becomes saturated, and the temperature at which saturation is reached, known as the dew point temperature creates condensation. When warm air is coming in contact with a colder surface it will deposit water droplets on the surface and since you outside temperature hits single digits all that condensation freezes and this is why you see so much ice up there. When outside temperature gets warmer, condensation starting to melt and you see the water starts to drip.

If they don't take care of it, you will get mold and your trusses and OSB will start deteriorating.

I don't think that roof vent will help, as a matter a fact it could make the situation worst.
Jeremy Zheng thanked GN Builders L.L.C
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Jeremy Zheng
Original Author
8 years ago
Thank you guys for suggestion. I scanned proch ceiling especial above my entry door find one more leak heat spot. all the leaking because of one heating duct across above entry door and poorly insulated. Spoken to builder, they agree to spary foam to insulate them.

Thanks for all your help
Vith
8 years ago
last modified: 8 years ago
Pic 4 they should remove the fiberglass and spray foam should be applied on that entire interior wall to seal it up. It appears on pic 3 that the side wall also needs spray foamed to be sealed up. Anything that shares a wall with the house interior pretty much needs sealed.

Probably do need a roof vent near the peak of the roof as well. Every time you open the door moisture escapes and ends up inside the roof.

Shouldnt be any ductwork/plumbing in that space... I dont see any reason for it.
Jeremy Zheng thanked Vith
Jeremy Zheng
Original Author
8 years ago
The Duct over the main entry door is leading to the bedroom over the garage. I think they just lazy want a short cut, but did not insulate properly. Builder will add a vent above the roof. I will report back after they finish all the mods to see how it goes
Ace T
5 years ago
Was the issue ever resolved? I’m having the same problem at my house.
PRO
GN Builders L.L.C
5 years ago
Have to seal the gaps, warm air escapes into the soffit from the house and freezes.