Frost on inside of attic sheathing

[Jeffrey A. Prince]

Hi
I was up in my sister in laws attic and I saw frost on her sheathing above the soffit vents. Ok I think I should be able to figure this out right. Insulation void right. But this is kind of weird. The house has a fairly big soffit at least two feet. The insulation covers the heated area and stops at the exterior wall. The pitch of the roof is steeper than most and there is no insulation blockage at the vents. If I told her to add insulation to the end of the soffit and add baffles I thought that would work but then I thought I would just be insulating a cold space?Bath fans are vented correctly. There is a ridge vent installed. What do you guys think? Sorry no pics I was just there putting something up in her attic

[James F. McKee]

are the ridge vents open and functioning properly Jeff?

[Jeffrey A. Prince]

They do, The sheathing is cut. I was thinking the same thing Maybe she needs more ventilation.

[James F. McKee]

usually frost on the sheeting is improper ventilation or moisture getting into the attic space, often a combination of both...I would not add insulation in the soffit area...pointless and could be a nightmare if any ice damming were to ever occur...

[Jeffrey A. Prince]

The only thing other thing I could think of that her attic hatch was not insulated I told her to insulate her attic hatch. Do you think the hatch could be the source . I am thinking more ventilation and insulting the hatch should help, I am going to measure the attic to see if she has enough ventilation

[Jeffrey A. Prince]

Not insulting LOL sorry. poor attic hatch Insulating

[James F. McKee]

attic hatches, can lights, basically any penetration through the ceiling as well as low R-value of existing insulaton...all these are possible contributors, but sounds like you are on the right track...

[ldapkus]

Do they have a humidifier? Almost all times I have been called to check out frost/condensation in attics, indoor relative humidity readings were in the 60%-80%+ RHI range. Warm air moves outward and meets cold air in building envelope and condenses.

[Jeffrey R. Jonas]

Remember though, the air movement 'should be' coming 'in' the soffitts, and moving 'out' the ridge vents. If working 'correctly', the moisture would have to be coming 'in' the soffitts, or leaking through the 'end' of the insulation 'at' the soffitts.

[ldapkus]

Jeff,
I had one in Downers Grove last winter that was "raining" in the attic from the frost melting on a sunny day. Water was also coming in through the can lights.

[Jeffrey R. Jonas]

Originally Posted by ldapkus

Do they have a humidifier?

If so, make sure it is actually working correctly. I removed mine two years ago... when turned down, it still ran at full flow.

Humidifiers on HVAC... bad idea! If needed, a stand alone unit is a better choice, IMHO.

[Jeffrey R. Jonas]

Originally Posted by ldapkus

Jeff,
I had one in Downers Grove last winter that was "raining" in the attic from the frost melting on a sunny day. Water was also coming in through the can lights.

WOW

[Jeffrey A. Prince]

no humidifier. I also do not like humdifiers. I just scratch like my dog when it gets dry LOL. It is weird the only place where frost and some condensation can be seen is above the soffit vents

[Jeffrey A. Prince]

I will have to take a better look to see if there any voids at the end of the insulation. I am kind of thinking that could be a source of heat leaking in to the attic space. I am going for sure see if ventilation is adequate and also insulate the hatch and see what happens. Thanks Guys

[Christopher Currins]

the only place where frost and some condensation can be seen is above the soffit vents

Missing insulation at exterior walls.