# Frost on joints in garage



## concretemasonry (Oct 10, 2006)

A classic example of the "thermal short-circuiting" from the studs. This also reduces the effective WALL insulation (R-value) of fiberglass (if you have it) from 15% to 50%. - Steel studs are very notorious for this loss.

If there is enough interior moisture, it will create frost in the areas with high conductivity.


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## ccarlisle (Jul 2, 2008)

What's the humidity reading in there and in your house? and at what temperatures did you take those humdity readings? Do you store your car there? Sounds like the builder forgot the housewrap, the insulation and/or the vapour barrier - or all three. Try keeping a fan going in there to keep the air circulating, The redo the whole thing (the drywall is toast).


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## Axecutioner-B (May 18, 2010)

Ahh, Mike Holmes would have a field day in that place.


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## Miko (Jan 2, 2011)

Hi everyone thanks for your help. When the weather gets better this week I am going to check for the house wrap and take a piece of drywall out of the interior to see what's behind the wall and let you know what's there. 

Regarding the humidity - it's not very humid in Calgary in general, say compared to Toronto. We're more dry like a desert as we're not around any large bodies of water. In the summer it's rare to go to 30c (dry heat, no humidex usually) and then in the winter -20 or so but known to hit -30c to -50c before the wind chill factor during a bad cold snap.

The only heat sources in the garage is when we park our cars in there after going out and then what heat radiates from the engines.


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## concretemasonry (Oct 10, 2006)

Even though you have a dry cold (similar to here, but only a little colder) your car can pick up some snow or ice under it and it is a source of moisture when it melts. and that will condense/freeze on a cold surface.

We get your weather here (Alberta Clipper) that drops a couple of inches of dry fluff one a predictable time schedule, followed by cold weather. - Unless we get some of the nasty southern winter weather, but that is usually south and east of us. You know when it is nice since the snow (if it is on the sidewalk/driveway) crunches very loudly.

Dick


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## Miko (Jan 2, 2011)

Hi all

So - I took a piece of drywall out, and there is vapour barrier and pink insulation under it. On the outside, I see black tar paper under the siding. The roof vents are covered in snow, not sure if that means anything. Also yes we get some snow in the garage from the car when we park it. Not sure though, given our climate and the detached garages here are all cookie cutter, aside from some being shingled with shakes (mine is asphalt) more people would experience the same problems, there must be something different with my garage?

Thanks


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## ccarlisle (Jul 2, 2008)

Peak in and tell us what the studs are made of...


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## Miko (Jan 2, 2011)

Studs are wood


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## concretemasonry (Oct 10, 2006)

Mico -

Sorry, but I did not read the original post close enough and assumed an attached garage that is warmer and the air can hold more moisture to condense/freeze on cold areas. In any event, you have moisture in the air to condense/freeze on the points of high conductivity. XPS insulation (pink or blue foam) does not exhibit the cold spots and thermal short circuiting, but you cannot change that now.

Dick


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## Miko (Jan 2, 2011)

If I were to tear down the drywall and take out the fibreglass insulation and replace it with that spray on stuff and redrywall, would that help at all? That spray stuff is supposed to be a vapour barrier in itself so plastic is not needed. I am not too familiar with the stuff though. As someone mentioned above.. Holmes seems to use it a lot.


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## Axecutioner-B (May 18, 2010)

Have you talked to any local contractors about it? Maybe it is something that one of them has seen before. I wish i had any good advice for you but I'm in Phoenix & hell we don't even get below freezing so our codes are very different, I've never seen vapor barrier except for on TV lol.


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## Miko (Jan 2, 2011)

Yeah.. haven't spoken to anyone really about it except my dad, it's just good to have a few opinions before talking to a contractor about it so I sort of know what's going on and don't get taken for a ride. I'll probably gut it all myself but pay someone who likes to drywall to do all that fun stuff themselves. It really baffles me though, if I really needed a circulation fan or something who knows what, I would have thought this would be a more common problem in this part of Canada.


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## concretemasonry (Oct 10, 2006)

As long as you have studs with no insulation barrier, the studs are the weak point and allow conductivity not matter what stuff is between them.

Dick


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## ccarlisle (Jul 2, 2008)

Yeah, but to get that much condensation/ice, you need really high relative humidity in that garage. It's around 45% RH outside in Calgary these days, same as us, at around freezing temperatures, so the inside must have a lot of moisture just hanging around and condensing everywhere. Close to 85% I'd say. It would help getting a reading in there...

So, lower the RH inside by using a heater and/or a fan. That'll patch it but something doesn't make sense if he has an air barrier under the siding, then fibregalss insulation then vapour barrier. Too high RH is the symptom, I'm not sure the cause...


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## Jackofall1 (Dec 5, 2010)

Looks like its time to move the drier vent to an outside wall.


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## concretemasonry (Oct 10, 2006)

At 45% relative humidity outside in Calgary, the outside air contains very little moisture in comparison to a warmer place like 45% relative humidity in Toronto since the air temperature is higher and the air can hold more moisture in Toronto.

You know when it is cold when you get a cloud of mist when the cold, dry outside air comes in and meets the interior air at the same relative humidity. THE DEW POINT IS A MORE REALISTIC WAY TO MEASURE THE AMOUNT OF MOISTURE IN THE AIR. I had problem at my lake home when I pulled my cold car into an attached, unheated garage, but it still fogged/frosted before I knew where to stop when it was -30F outside.

Humidity, condensation and fogging/frosting just take time to fully understand and it can be confusing and conditions are always changing by the hour or day.


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## jbl (Jan 5, 2011)

*garage frost*

Our garage started with frost accumulation on all drywall screws, door handles and locks. The windows get completely frosted over. We just received a new roof a couple of months ago and it didn't do this before. anybody know what might be the cause? It is insulated and drywalled too. Only moisture comes from our vehicles, but is that enough? Our frost is not nearly as much as the other gentleman, but it's enough.


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## Miko (Jan 2, 2011)

Thanks everyone. I think we're going to install an exhaust fan with a timer and see how that goes.

As for the frost amount - the flash does exaggerate it a bit.. but not by much. The door lock and handles and hinges are the worst.


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## CplDevilDog (Mar 18, 2009)

I wonder if the vapor barrier was left out when they poured the slab. Could be moist air moving through the slab.

Might want to paint the floor in oil based paint or epoxy


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## Miko (Jan 2, 2011)

Well I installed a fan with a humidity switch and it seems to be working, but there is still some buildup in areas. Not as much, the fan is helping, but probably not to full expectation. Might need to put a small heater in there to heat it up just above freezing when it's very cold.


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## masterofall (May 27, 2010)

My guess is excass humidity from the cars bringing in snow on the inside. Thermal bridging causing the moisture to condense and freeze on these cold spots. Are your walls 2X4 or 2X6. I'm guessing 2X4. It could also be a very bad insulation job. Attic access should be code. In Vancouver many homes have permanetly "on" bathroom fans to remove the excess moisture in the winter. Some heat in there would help


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## Miko (Jan 2, 2011)

masterofall said:


> My guess is excass humidity from the cars bringing in snow on the inside. Thermal bridging causing the moisture to condense and freeze on these cold spots. Are your walls 2X4 or 2X6. I'm guessing 2X4. It could also be a very bad insulation job. Attic access should be code. In Vancouver many homes have permanetly "on" bathroom fans to remove the excess moisture in the winter. Some heat in there would help



Thanks yeah, I think I may have to heat it a bit, but the fan is helping with 90% of the ice. Of course it wasn't around -30 for a couple of weeks this time, just a couple of days. 2x4 walls i think, insulated with fibreglass pink, attic has R20 fibreglass pink. vapour barrier on walls and ceiling. tar paper on outside walls under siding.


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## DRM123 (Feb 23, 2011)

Miko I have the same problem, not quite as bad as your pictures show, but frosty just the same. I'm out in Airdrie so pretty much the same weather. Who built your garage for you? I haven't checked for the house wrap yet, wanted to wait for the warmer weather, but I'm thinking my builder took a short cut and didn't wrap the garage


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## Miko (Jan 2, 2011)

DRM123 said:


> Miko I have the same problem, not quite as bad as your pictures show, but frosty just the same. I'm out in Airdrie so pretty much the same weather. Who built your garage for you? I haven't checked for the house wrap yet, wanted to wait for the warmer weather, but I'm thinking my builder took a short cut and didn't wrap the garage


Hi, not sure who did, it was built a few years after the house was. 

Go to Home Depot and get that $150 bathroom fan with the humidity sensor so it runs when it needs to. It's 100 sones and barely audible so it won't bug the neighbours. 

It will get rid of about 90% of the problem but I am still waiting for a week below -30. Since the recent cold snaps though the frost is no existent except the odd spot here and there. Buddy said I might need to heat the garage to around 5c if there's a long deep cold snap.


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## Gary in WA (Mar 11, 2009)

The studs are acting as thermal bridges, being colder than the wall cavities, the moisture is condensing on the drywall directly over them; pp.10; http://docs.google.com/viewer?a=v&q...fBrOrJ&sig=AHIEtbSk4qNS_4vQRnyKBiEiG1lHFDd9yA

Notice the mass where the door header is because 3-1/2” solid wood has a R-value of 4-1/2-, while the cavity is R-11; http://www.coloradoenergy.org/procorner/stuff/r-values.htm

Ventilate. Or install rigid foam board, then drywall on the studs to break the bridge, as said.

Gary


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## antlerdancer (Oct 6, 2009)

I was doing some drywall finishing in a buddys garage that had the same problems. I found out that he had blown in insulation in the attic and the dust had blocked the screen on the ridge vent. You had mentioned that the roof vents were covered in snow. I would give that a serious look. Good Luck and its almost SPRING:laughing:


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