# Mold in detached garage



## Ron6519 (Mar 28, 2007)

Another issue is the mold behind the wall. Nothing you will do to the visable surface will fix that. If branches hit the roof and damaged it, there would be visable evidence on the roof. Do you see anything?
Is the ceiling covered in drywall? Can you see the roof sheathing from inside the garage?
You need to remove all the affected drywall . Start in the middle and work out to the edges. Keep removing it until you get no mold on the back surface. Leave the area open until the water source is fixed and the wood is dry. You will need to treat the area once it is exposed.
Your method just conceals the problem and it will continue to grow behind the walls.
Ron


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## jkrodger (Jul 10, 2007)

Ron,
There is no drywall in the garage, only the wood framing and wood slates.


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## Ron6519 (Mar 28, 2007)

How high on the wall is it wet?
Ron


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## jkrodger (Jul 10, 2007)

pretty much to the top of the wall...about where the seam with the roof is. The mold doesn't go up that high, but the wetness appears to. 

Someone just posted a picture of his garage wanting to know about insulation and such. That picture is pretty similar to my garage.


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## Ron6519 (Mar 28, 2007)

Posting a picture on the exterior would help cut down on unnecessary speculation of issues not in evidence. Such as ; ice dams, frozen overflowing gutters, roof shingles that don't overhang the roof edge enough to keep water from getting behind the fascia board, rotted fascia board and so on and so on...
Ron


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## oraclesdaughter (Apr 23, 2009)

*mold*

Hey there - Did you find success in killing the mold? We converted our unheated garage roof to a deck and then had it resided last fall. Stupidly, I did not know that the garage needed to be vented or heated & our contractor didn't inform us of this either. As a result, we have some pretty bad mold growing & some of our plywood warped (the interior is all exposed plywood & support beams from the original structure; not wolmanized.) Obviously I need to start with killing the mold. Went to Home Depot today & decided I should do a bit of research prior to buying a product to kill the mold. I am open to any suggestions. Thanks.


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## Ron6519 (Mar 28, 2007)

oraclesdaughter said:


> Hey there - Did you find success in killing the mold? We converted our unheated garage roof to a deck and then had it resided last fall. Stupidly, I did not know that the garage needed to be vented or heated & our contractor didn't inform us of this either. As a result, we have some pretty bad mold growing & some of our plywood warped (the interior is all exposed plywood & support beams from the original structure; not wolmanized.) Obviously I need to start with killing the mold. Went to Home Depot today & decided I should do a bit of research prior to buying a product to kill the mold. I am open to any suggestions. Thanks.


 Garages do not need to be heated or vented to prevent mold. They just need to keep water from getting in.
How do you convert a garage roof to a deck? Did you put a deck on the garage roof? If the garage wasn't leaking before the deck installation, it was probably the contractor who created the leak.
Post some pictures of the deck and where the mold is, in the interior.
Ron


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## oraclesdaughter (Apr 23, 2009)

The roof was completely removed, 6 x 6 beams were added structurally to the standing frame, 27 trusses were then placed with the deck being built on top. The deck was angled for proper run-off and heat sealed. (I know I'm probably not using all the right terminology) and then a level deck on top. I do not think the roof is leaking. Here's where I believe the problem came from - we had always had run off from the alley into the garage due to a slope and an untight garage door. A new apron was supposed to be placed but was not gotten to before winter. Then the contractor urged us to finish the siding (not insulated but tyveked) so that the plywood wasn't ruined in all the Chicago rain & snow. It became much more air tight but water could still get in under the door & did. I had no idea that the mold was building until recently. I will take a photo tomorrow in the daylight & post. Thank you!!


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## oraclesdaughter (Apr 23, 2009)

*Mold moisture source*

Good morning. Well the light of day (& the first warm sunny day in months) has revealed that you (Ron6519) are right - the water was coming from above. It appears that the water has run down the sides of the 6 x 6 posts. When it dries we will apply clear silicone caulk to seal all the seams around the the beams.
The mold still needs to be remediated. I have attached photos. (2124 shows the plywood that is the worst - it is actually rippled.) help.


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## Ron6519 (Mar 28, 2007)

Caulking the posts will not give you a long term solution. When the roof was heat sealed the deck posts should have been incorporated into the mix.
You need to get the contractor back to fix this or the deck will rot in a heartbeat. I seriously question the use of OSB as a substrate in this situation.
Right now the siding needs to come off so the damaged plywood can be replaced. It's really odd that over one winter an exterior grade plywood would show that much damage. Check to see the stamps on the wood say exterior ply or CDX(x for exterior)
I also see pressure treated wood mixed into the top plate construction. Did the contractor use the correct fasteners? All you can use in this wood is hot dipped galvanized and stainless steel. Over time, the chemicals in the wood will eat regular steel nails.
Ron


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## oraclesdaughter (Apr 23, 2009)

*New question after mold fixed in garage*

Thanks for the info. You have confirmed the information we received from others. The siding is going to come off & things will be recified. (Sigh.) THank you.

Assuming that we rectify the mold situation and get what need to be replaced replaced - does a garage (with no leak) need to be heated or have a vent in order to prevent interior frost (& a repeat of mold possibly) during the winter?


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## Daniel Holzman (Mar 10, 2009)

The previous post regarding the need to heat the garage is accurate. There is NO NEED to heat a garage to prevent mold, frost, or any other water problems, there is an absolute need to KEEP THE WATER OUT OF THE GARAGE in the first place. Mold requires three things to grow, moisture, a substrate like wood or sheetrock, and a warm enough temperature. Put those three together, you will have mold. Therefore, heating your garage will make a mold problem worse, not better, if you have moisture present.

Similarly, frost cannot form if there is no moisture, so if you keep it dry, no problem.


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## Ron6519 (Mar 28, 2007)

Dan said it already. No moisture, no mold.
The leak should be fixed before the damaged wood is replaced or the new wood will fall to the same fate.
Ron


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## oraclesdaughter (Apr 23, 2009)

Thanks guys. I suspected that some of the previous info I had received didn't make sense. It is raining pretty hard so I guess I'll find out soon enough whether the leak is remedied.

I spoke with a mold expert who has a remediation business. He has suggested forgoing the use of "off the counter" products and bleach and recommended (with instruction &/or referenced workers) a biocide (Foster 40-80) followed with an encapsulant (Foster 40-25) for any wood not replaced. I am being a task-master on this project now and taking the time to do each step right. I know that my guys are going to want to do some bleach mixture but I say no. I have no problem sticking to my guns now that I have armed myself with the knowledge of the science behind the issues; but is that overkill? 

Ironically, we have had significant water leaking under our garage door during rains for 5 years and never ever had a problem, no frost, no mildew, nothing - I have even stored my closed work document files in there (a soggy mess after this.) (A new apron is going in hopefully next week to at long last solve that issue.) Needless to say, this has been discouraging. Again, thanks for the back up.


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## norble (Apr 26, 2009)

Thank you all for your responses....Norbletheoracle!


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