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Discussion Starter · #1 ·
I have a 12 by 16 room that is up off the ground I want to put r13 under it I was going to put it up and then put some osb up so that the dog and cats can not get in to it I know that the osb is more than I need but the price is good on it and the room is small so I was thinking I will get some more r out of the osb but others have been telling me that I will get mold if I use osb to cover it up and are tell me to put wire up the insulation has a vapor block on both side it is like it is in a plastic bag but it has small pin hole in it I have the osb and can take it back can some one pleas tell me the best was to do this I live in Louisiana thanks
 

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Not sure what is correct down south. Up here in this climate, I would use rigid foamboard insulation since, it open to the weather. Might cause moisture problems down south. Check local codes or practices. They do make insulation already in plastic bags. But I would add more that R13, if possible.
 

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Due to the humidity levels under the house I would paint the osb with a good exterior paint.
I would also ask, are you sure the R13 is enough?
Ron
 

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Discussion Starter · #5 ·
Due to the humidity levels under the house I would paint the osb with a good exterior paint.
I would also ask, are you sure the R13 is enough?
Ron
R13 is what is call for here in wall and floor not real cold here for long time in winter just short freeze time one or two time a year and back up in the 50 by noon Thank you for telling me about the exterior paint.
 

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Discussion Starter · #6 ·
what about spray foam.where i live you can rent the equipment
we do not have that here I went to Lowe's and asked and look all we have is the foam in a small spray can and it would cost to much to use but thank you for getting back to me
 

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Hey, grillman, sounds like you're in south La. Common practice over here in homes on pier and beam foundations is just kraft faced fiberglass, with the facing up against the floor and installed with wire supports. I like the perf encapsulated better, though. I wouldn't put the osb under it. You'd not only have the possibility of mold, but it would create the kind of space that roaches like to breed in if it does trap any moisture. That said, it might last a long time without any problems, but if they do occur it's a real pain in the butt. Not worth taking the chance to me.
As far as the animals go, dogs and cats usually won't bother it, though I've known a few dogs that would chew on just about anything:wink: I'm more concerned about raccoons and possums under the house. Best thing is to skirt the house with lattice, either treated wood or pvc, to keep them out and still let it breathe. Looks better, too. You should also put down a 6 mil plastic sheet on the ground under there if you don't already have it.
The only thing I've ever seen messing with the exposed fiberglass is mockingbirds stealing little bits of it when they're building nests, but they usually won't go through the lattice to get it.
 

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Do you use AC in this room?
If so more insulation would help on that cost
Good point, Dave. More is always better, IMO. I prefer to use R19. Down here, though, if it's just a crawl space where the wind doesn't really blow through it R13 is adequate. IIRC, DOE recommendation for floors here is only R11, but I always take those to be absolute minimum. Close to water, where the piers are 8' or taller, R19 is the standard and those can be safely enclosed without moisture problems....at least until the surge comes:eek:
 

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If it's well ventilated underneath then I don't see the harm in adding the osb. It wouldn't be any more prone to condensation than the walls are covered with siding. Key words are well ventilated.
 

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Key words are well ventilated.
Yup, and a good ground barrier. If it's on high ground with good drainage can make a difference, too. From what I've seen in the few years I've been down here, though, I won't enclose it unless it's at least 4' off the ground. But that's just me....I hate mold and roaches:censored:....thinkin' seriously of moving back to a drier climate in a couple years:yes:
 

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roxal insulation is not bothered by water and if you wanted to put the osb under there what about taking a piece os peg board(the one with all the holes in it) and ripping it down to 1 foot by 8 foot strips and putting 2 rows of it in there for ventalation.you could paint everything with thompson water sealer before putting it up (both sides)
 

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Let's not get too crazy about the more insulation the better. Everytime you double insulation you reduce your heat loss by half. That means:

R1 saves 50% heat, and loses 50%
R2 saves 75% heat, and loses 25%
R4 saves 87.5% heat, and loses 12.5%
R8 saves 93.8% heat, and loses 6.3%
R16 saves 96.9% heat, and loses 3.1%
R32 saves 98.4% heat, and loses 1.6%
R64 saves 99.2% heat, and loses 0.8%
R128 saves 99.6% heat, and loses 0.4%

At R13 he saves 96.15% of the heat/cold and loses 3.85%. If he moves up to R26 instead he's going to reduce his heating/cooling through the floor by just 1.92%/year and still lose the same through the walls & attic. So, insulating the floor to R26 vs. R13 probably won't even save 1% to his total heating/cooling bill. It may be worth it to insulate it higher than R13 if it's real easy and cheap to increase the insulation, to be green :), or the owner expects to live many years in the same place.

In high moisture areas as mentioned I'd paint the OSB and use XPS foam which is impervious to moisture and the right tool for the job in water/moist/ground/basement type situations. Just make sure none of the XPS is exposed to sunlight, sunlight slowly turns it to dust.
 

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Let's not get too crazy about the more insulation the better, especially dealing with foam. Everytime you double insulation you reduce your heat loss by half. That means:

R1 saves 50% heat, and loses 50%
R2 saves 75% heat, and loses 25%
R4 saves 87.5% heat, and loses 12.5%
R8 saves 93.8% heat, and loses 6.3%
R16 saves 96.9% heat, and loses 3.1%
R32 saves 98.4% heat, and loses 1.6%
R64 saves 99.2% heat, and loses 0.8%

At R13 he saves 96.15% of the heat/cold and loses 3.85%. If he moves up to R26 instead he's going to reduce his heating/cooling through the floor by just 1.92%/year and still lose the same through the walls & attic. So, insulating the floor to R26 vs. R13 probably won't even save 1% to his total heating/cooling bill.

In high moisture areas I'd paint the OSB as mentioned and use XPS foam (just make sure none of the foam is exposed to direct sunlight, the sunlight will turn it into dust).
Do you have a link to where these numbers come from?
Thanks
 

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I'd still use something thicker than r13. I feel like that's a wasted effort. Spend an extra few dollars and put something in worth using. I may be off base since heat loss is more of a concern here but I believe code is r30 under the floor. I don't think you could even get away with r13 in a 2x4 wall here
 

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Discussion Starter · #16 · (Edited)
thank you every one

I hope I am doing this right thank you to every one that had gave me there points and the do and the don'ts it has been so help full you will never know how much the job it complete now I used fence wire from one of the post that I got I never thought that I would get so much help thank you all so for we have had a lot or rain and I have been pulling it open and checking for mold and thank God so far so good and it is drying out good the only thing now is my dogs think that is there new home under there as for keeping it cool we have had some 101 Temp here after we completed the small room and my son keeps it a 68 in there all the time and the air compressor go off and on it takes about 15 min to cool it down if the air is off and it is about 98 out door it will be about 80 in the room I put a 1500 BTU window air in the room my light bill went up $40 but he has a small Icebox and play xbox 360 and a TV in there I think that putting insulation in the walls roof and floor has paid off my son has told me that a night he has to turn the air off because it is to cold I can not wait for him to get out of collage and go on his own so that I can use the room for a place to get away and watch the game or I may try that xbox 360 we put the Internet in there it will be my dog house but I do not think he is going to out move no time soon but that is ok it is cheaper to have him here than pay rent :thumbup:
grillman39
 
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