Help! Garage Walls Are Turning Green!

[Chris702]

I live in Washington State and have a home that's almost 3 years old with an attached unfinished garage. The wall that is attached to the house has drywall on it and so does the ceiling but the remaining 3 walls are unfinished. On the exterior its T1-11 so there is a visible vapor barrier on the interior on the back side of the studs. Last night I noticed that this white vapor barrier has turned a shade of green for about the bottom 3 feet on every wall. There are no leaks in the garage but since this is Washington we do park a wet car in the garage. I talked to the builder and he said no obvious leaks since it is happening on all walls and the garage is pretty air tight when the door is sealed up so parking a wet car in the garage can lead to moisture build up which can lead to mold growth. How can I remedy this? If I drywall the walls will this help? I am a bit lost, it is Washington State so its wet. I cant be the only one with this issue. Just makes it worse because its a new home and the builder is basically telling me don't park a wet car in the garage and it wont happen!! And advice??

 

[jeepinerdeep]

Insulate and condition it would be my guess.

 

[BillK]

Dehumidifier ??

 

[imjustdave]

been in WA state for 30+ years don't recall green mold on my garage walls.

do you have vents in roof above? or is it 100% 2nd floor. I suspect you need some ventsvents in general.

mold could be from when they built as well. go visit neighbors and ask them to compare.



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[Chris702]

been in WA state for 30+ years don't recall green mold on my garage walls.

do you have vents in roof above? or is it 100% 2nd floor. I suspect you need some ventsvents in general.

mold could be from when they built as well. go visit neighbors and ask them to compare.



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I have lived in Washington for my whole life and never seen such a thing. I would say my garage is pretty damp in general just from my wife's car and the garage is only opened a couple times a week I am sure the air gets pretty stagnant. My neighbors have the same things but they both use their garage for storage so no water in it.

The roof above the garage is vented but no vents in the garage itself, so once the doors are closed it's pretty air tight with the water trapped inside.

 

[csi123]

Are you sure it is mold? You may want to have it tested first before you do anything. The way you describe it sounds a bit too uniform to be mold.

 

[Leaflessshadetree]

I would imagine that what you are calling a white vapor barrier is actually house wrap. If so it is not a vapor barrier. It is a moisture barrier, and probably what you want.
I'd start by washing it down with a bleach solution. See if it comes back.

 

[CraigStu]

Today's houses are super tight. Our 1.5 yr old house in SW Virginia had to pass a vacuum test to get the occupancy permit. My garage is insulated and drywalled just like the house. When I open or close the man door in the back I can hear the garage door moving on it's rollers so the garage is tight also. I bet the OP's is similar even though not finished. Once confirmed it is actually mold, I'd get a dehumidifier. You could mess around w/ a fan and a gable vent but it would take 3-6 months to figure out if each attempt is a fix. Mount the dehumidifier 1-2 ft off the floor so gravity works for you and drill through the side wall for the drain to the outside. Be sure to extend the drain hose away from the foundation like you do w/ a down spout.

 

[yeldogt]

I think you need some pictures ......

It does sound as if maybe the builder put up house wrap and then the T1-11 and you are seeing the back side of the wrap.

If this is the case ... the moisture in the garage is condensing on the cold wrap/ T1-11. Currently you have a tight enough space to not allow moisture to leave the garage .. but, not enough insulation to stop the condensation.

You need to move forward and finish the inside -- or create a way to exhaust the moist air when you bring in a wet car in. I have an occasional day or two where the temps allow for humidity to exceed what I would like in my garage. Most times an insulated garage will be fine ..

Green is going to be algae -- hit it with a mild bleach solution mixed and applied with a spray bottle

 

[BillK]

Just want to say that several people are suggesting you use bleach to kill what is there. I dont know if i would do that without being sure that the bleach will not hurt the Tyvec or whatever other building wrap you have. Bleach is pretty terrible on plastic.

I still think a dehumidifier is going to be the easiest solution.

 

[Chris702]

I tried to get a decent picture but it is just not capturing the green tint very well. This was the best I could come up with, keep in mind it does look much more dramatic in person. Basically it effects every unfinished wall of my garage from the level of the electrical outlet down to the bottom of the wall. I seen a post above mention algae, maybe that is more correct than a true mold? I tried to wipe it off just using a couple of Clorox wipes we had in pantry and it did nothing, it did not remove the green tint at all.

Since I am only having this issue on the house wrap or vapor barrier (whichever it is) think I could just get away with throwing up some sheet rock and finishing my garage? Or will insulations really help that much? I don't have a insulated garage door, nor did I plan on getting one and with my attic storage I have I couldn't do more than 3-1/2" of insulation for the center 1/3 of the attic area if I attempted to insulate up there.

 

[BillK]

The interesting thing is that it only seems to be on the white surface but not on the wood studs. Maybe the wood is absorbing the moisture in the air but it just sits on the plastic stuff. Does the plastic ever feel "wet" after you park a rainy car in there ?

 

[BillK]

By the way if thats all you have after three years I would say that it isnt too bad. It might just be from dirt in the air. Try some Fantastic or similar cleaner and see what happens.

 

[Chris702]

The interesting thing is that it only seems to be on the white surface but not on the wood studs. Maybe the wood is absorbing the moisture in the air but it just sits on the plastic stuff. Does the plastic ever feel "wet" after you park a rainy car in there ?

Yes the plastic does feel "damp" on occasion, I know there is humidify in the air as I can open my tool box and some of the tools are "sweating".. That might answer the problem, as someone noted above just get a dehumidifier.

As someone else mentioned, yes my garage is sealed up tight, when I open/close the door from our utility room to the garage I can hear the overhead door moving on its tracks just from the air pressure movement.

 

[BillK]

Yes the plastic does feel "damp" on occasion, I know there is humidify in the air as I can open my tool box and some of the tools are "sweating".. That might answer the problem, as someone noted above just get a dehumidifier.

Yup, sounds like the moisture is the problem and a dehumidifier will be the cure.

 

[HaiKarate]

Are you sure it's not just pollen? I get tons of that **** on everything at our place - builds up in corners/crevasses, etc. Not easy to 'wipe up' once it goes through a wet/dry cycle or two.

 

[pvfjr]

I feel your pain. We just bought a house next to a river in a Cascade Foothills rainforest. This location gets about 80 inches a year, and the river is about 200 feet away. The sun is too low in the sky in the winter to ever make it over the ridge or through the trees (assuming the sun is even "out"), so nothing ever dries out. We just moved in October, and I haven't seen the humidity drop below 95% outside since then.

Our summers will be drier since it's the PNW. I know most people on this board only have humidity problems in the summer, but everything is backwards here.

Our attached garage seems OK for humidity, but our detached shop, shed, and barn have problems. I hung my trusty old jacket on the wall for a month, and it's completely covered in mold. My wife stuck a bunch of my backpacks in the shed, and they're covered in mold now as well. A closer look revealed a couple old Driz-air fixtures left from the previous owner, and a few bags of salt. I'm going to refill the bags and see how it goes.

I'm thinking about getting some remote sensors and datalogging the humidity so I can be certain of the difference made by any solution I try.

 

[Chris702]

Are you sure it's not just pollen? I get tons of that **** on everything at our place - builds up in corners/crevasses, etc. Not easy to 'wipe up' once it goes through a wet/dry cycle or two.

Is pollen green? I always thought it was yellow?

 

[Trapps]

Perhaps the wrap/barrier is oxidizing, after time, with contact with the T-111 on the exterior surface - this would explain why the Clorox wipes had no effect on the inside. Is there a section you might access the exterior side of the wrap/barrier and try again? Another cockamamy theory is perhaps it is staining from the sill plates which I assume (stupid me) are PT and it's leeching up due to capillary action in the T-111?

Yep, complete SWAGs here...

 

[LS6 Tommy]

Yup, sounds like the moisture is the problem and a dehumidifier will be the cure.

Save the money. You said the space was "tight". Get some ventilation first.

Tommy

 

[Youngandfree]

Just want to say that several people are suggesting you use bleach to kill what is there. I dont know if i would do that without being sure that the bleach will not hurt the Tyvec or whatever other building wrap you have. Bleach is pretty terrible on plastic.

I still think a dehumidifier is going to be the easiest solution.

Bleach is corrosive to metal, it doesn't hurt plastic at all. It's used to wash green mold and algae off plastic houses all over the country on a daily basis.

 

[Youngandfree]

I tried to get a decent picture but it is just not capturing the green tint very well. This was the best I could come up with, keep in mind it does look much more dramatic in person. Basically it effects every unfinished wall of my garage from the level of the electrical outlet down to the bottom of the wall. I seen a post above mention algae, maybe that is more correct than a true mold? I tried to wipe it off just using a couple of Clorox wipes we had in pantry and it did nothing, it did not remove the green tint at all.

Since I am only having this issue on the house wrap or vapor barrier (whichever it is) think I could just get away with throwing up some sheet rock and finishing my garage? Or will insulations really help that much? I don't have a insulated garage door, nor did I plan on getting one and with my attic storage I have I couldn't do more than 3-1/2" of insulation for the center 1/3 of the attic area if I attempted to insulate up there.

Try wetting an area with diluted bleach mixed 50/50 with water and keep it wet for a couple minutes. Strong enough bleach will turn it white fairly quickly, and wipe off. Just wiping with a Clorox wipe isn't strong enough.

If that works, you could potentially use a pump sprayer and mist it on, let it swell, and wipe it off. Ventilation and respirator is highly recommended.

 

[HaiKarate]

Is pollen green? I always thought it was yellow?

It's generally yellow-ish when it falls, but add in dirt/dust/water/time/etc. and it can darken and look green where it builds up.

 

[csi123]

I seen a post above mention algae, maybe that is more correct than a true mold? I tried to wipe it off just using a couple of Clorox wipes we had in pantry and it did nothing, it did not remove the green tint at all.

Usually mold lives on the surface, regardless you should have it tested before doing any corrective action.