Help with vapor barrier had some mold growth


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Old 04-18-15, 12:48 AM
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Help with vapor barrier had some mold growth

I used rmax 1/2 and furring strips last year started measuring for cabinets and noticed surface mold on the unfinished drywall at the outlets and some screw holes. (Not black mold) I removed the drywall and noticed mold growing on the back side but only where the furring strips were touching the drywall. I replaced 90% of the wood when I replaced it couple years ago. Was i supposed to use a barrier? exterior wall,block home, stucco outside.


I plan on bleaching the wood (letting dry couple of days) then putting in the unfaced insulation and the 6mil plastic up, then drywall.

Would this be correct I live in FL.
 
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Old 04-18-15, 04:39 AM
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There has to be a reason why the mold is there, in the first place. Is water entering from the outside? Whatever the reason is, it has to be corrected first.
 
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Old 04-18-15, 05:55 AM
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Is this above or below grade? What is your location?

Edit. I didn't notice you said you were in Florida. In Florida, your vapor barrier needs to be against your block wall, then your furing strips and drywall.

What is happening is warm moist air in coming in from the outside and condensing on the bsck of the cool conditioned drywall. The moisture under the furing strips is trapped and does not dry out as fast as the rest leading to mould growth.
 

Last edited by Keith Weagle; 04-18-15 at 06:39 AM.
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Old 04-18-15, 05:59 AM
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Most of the fla block homes I've worked on had the furring strips, insulation and then the vapor barrier under the drywall. Is the exterior stucco painted? Do you run your HVAC system regularly to reduce the humidity?
 
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Old 04-18-15, 07:21 AM
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I tend to agree with Keith. In a hot humid climate the vapor barrier goes to the outside (the warm side). But I'm a long ways from those warm humid climates so here are a couple of articles for reading.

Home Energy Magazine :: When Wall Insulation Doesn't Save
Vapor Barriers Are a Good Thing, Right? | GreenBuildingAdvisor.com
What Happens When You Put a Plastic Vapor Barrier in Your Wall?

In fairness I admit to not carefully reading these articles, but have read many, so if you find questions, just direct me and I will give it some time.

Bud
 
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Old 04-18-15, 09:09 AM
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If he was running Rmax in 1/2", would that not constitute a vapor barrier if taped off? That being the case the vapor barrier under the sheetrock was redundant, and possibly keeping the air space from breathing. Don't know nuthin about Florida construction methods.
 
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Old 04-18-15, 10:38 AM
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When i did the tear down, it went fur strips unfaced insulation then vapor barrier. But then my house was built in 86.

I dont run my a/c as much as probably should I set it at 79. The stucco is painted.
 
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Old 04-18-15, 02:11 PM
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I painted a lot of new houses similar to yours in central fla all thru the 80s and what you described was SOP.
 
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Old 04-18-15, 04:00 PM
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What does SOP mean? Thanks in advance.
 
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Old 04-19-15, 03:15 AM
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SOP - standard operating procedure
 
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Old 04-19-15, 05:24 AM
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jp, so you don't feel alone I hate acronyms. With all of the technology we have today I'm convinced they are used just to annoy people. It would be very simple to add a pull down box where the author could select or add to the optional meanings for every abbreviation known. Then the readers would just mouse over and see what the heck the author was talking about. So simple and it would quickly become SOP. Sorry, couldn't help that .

Bud
 
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Old 04-19-15, 06:05 AM
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To make it worse, some acronyms have more than one meaning.
SRO standing room only or single room occupancy
ATM at the moment or automatic teller machine
ATF automatic transmission fluid or alcohol tobacco & firearms
 
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Old 04-19-15, 06:37 AM
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Even in my own trade I find people just grabbing the first letters of some phrase to create their own short hand and it leaves me searching the internet, often unsuccessfully, for their meaning.
Mouse over, mouse over, mouse over. I find if we say something enough on the internet that someone will grab it and run, hopefully.
Sorry for drifting jp.

Bud
 
 

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