# Crawl Space Project Cont....



## Windows on Wash (Aug 30, 2011)

No need to wrap the duct work in a conditioned crawl.

You should seal the seam and control ventilation via a metered register rather than relying on accumulated leakage to condition the crawl.

Always better to be able to meter the air and than just via leakage.

Looking good so far. :thumbsup:


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## cbaur88 (Jan 25, 2011)

Windows on Wash said:


> No need to wrap the duct work in a conditioned crawl.
> 
> You should seal the seam and control ventilation via a metered register rather than relying on accumulated leakage to condition the crawl.
> 
> ...


Thanks again WW for you help and input. I agree and really wanted to add a register or two off the main supply to the crawl space but over in HVAC I am being told I need to add a return vent in the crawl space in order to do that. That is something out of my league and something I can't afford to hire someone to do the work as my return is far away and would need some bit of work it appears to accomplish.

Attached are some quick snap shots of the updated project. Thanks again much for your help! 

P.S. The humidity level is pretty high down there now 65 - 70% but I do not have a proper vapor barrier in place. I am hoping that once I get that installed securely and tightly that will reduce down to around 50% or less if not I'll be adding a dehumidifier I suppose.


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## Windows on Wash (Aug 30, 2011)

You will be fine with just a bit of supply side air. You are basically pushing that in there now with all the duct leakage and there is plenty of air moving up to the first floor.

Seal all the seams in the ductwork and open up one supply register and see how that goes. If you sealed up everything so tightly that the air can't get out, you can re-examine the return vent then. The reality is that the crawl/home connection is probably not as tight as you think and air pushed into the crawl will make it through to the home.

This is why it is imperative to get the floor completely sealed up tight like a drum.


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## cbaur88 (Jan 25, 2011)

Windows on Wash said:


> You will be fine with just a bit of supply side air. You are basically pushing that in there now with all the duct leakage and there is plenty of air moving up to the first floor.
> 
> Seal all the seams in the ductwork and open up one supply register and see how that goes. If you sealed up everything so tightly that the air can't get out, you can re-examine the return vent then. The reality is that the crawl/home connection is probably not as tight as you think and air pushed into the crawl will make it through to the home.
> 
> This is why it is imperative to get the floor completely sealed up tight like a drum.


Makes allot sense WW, thank you again. I am monitoring my crawl with wireless temp/humidity gauge. Once I am finished with the project and I've got the vapor barrier down I will monitor humidity levels/temps to see if I should add more conditioned air or needing a dehumidifier.


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## Gary in WA (Mar 11, 2009)

Fig.2: http://www.buildingscience.com/documents/information-sheets/crawlspace-insulation/

Rims are at R-2; http://www.quadlock.com/technical_library/bulletins/R-ETRO_Value_of_Basement_Insulation.pdf

Gary


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## cbaur88 (Jan 25, 2011)

GBR in WA said:


> Fig.2: http://www.buildingscience.com/documents/information-sheets/crawlspace-insulation/
> 
> Rims are at R-2; http://www.quadlock.com/technical_library/bulletins/R-ETRO_Value_of_Basement_Insulation.pdf
> 
> Gary


Good stuff Gary, thanks. I've got the rim's all sealed up best I could :thumbsup:


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## CrawlSpaceMoist (Nov 24, 2011)

What a great job, and thanks for posting this info! If you enjoy it you could start your own company, but you'll have to pick the pace up a bit! 
Also, I thought returns in sealed crawls weren't allowed? Maybe I misunderstood, but you mentioned that's what was being said over in the HVAC area...
Good luck, keep us updated. 65%-70% humidity is high, but I'm curious how much it would drop if:
1. you just added the poly to the floor
then:
2. added the supply air.

The last sealed crawl I saw with no conditioning (thursday) was about 58%. he had a dehumidifier, just hadn't had electric run into the crawl yet.
JP


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## cbaur88 (Jan 25, 2011)

CrawlSpaceMoist said:


> What a great job, and thanks for posting this info! If you enjoy it you could start your own company, but you'll have to pick the pace up a bit!
> Also, I thought returns in sealed crawls weren't allowed? Maybe I misunderstood, but you mentioned that's what was being said over in the HVAC area...
> Good luck, keep us updated. 65%-70% humidity is high, but I'm curious how much it would drop if:
> 1. you just added the poly to the floor
> ...


Thanks CSM, sometimes I feel like I could do it for a living after all I've learned from the fine folks on this forum and the information I've read on the internet. But I know there's much more to be learned.

Yeah I am not sure about the return in the crawl. That's what the HVAC was telling me at least this one particular gentleman was telling me. I am not sure if that's allowed or not. 

Just yesterday I removed the fiberglass wrapped around all my duct work. I already see a difference in temperature of the overall crawl space and a lower humidity as well but not much. So it appears some of the leakage must be getting out into the crawl conditioning it a little. I'll see if this leakage and the vapor barrier make a dent in the humidity level. I hope it does as I'd hate to incur the cost of a dehumidifier. Thanks again and I'll keep you posted.


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## metal (Sep 8, 2011)

Wow looks like quite the project. I get far too closterphobic in areas like that. Props to you!!


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## ndmick (Jan 26, 2012)

I`ve been doing alot of reading here for weeks.When the vapor barrier is put down does it go up the insulation and about how far?I`ve got alot of projects coming fast,Pex water lines,insulating conditioned crawl space,new bath,new kitchen.I`m planning on doing it mostly by myself.I live in south carolina.


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## cbaur88 (Jan 25, 2011)

ndmick said:


> I`ve been doing alot of reading here for weeks.When the vapor barrier is put down does it go up the insulation and about how far?I`ve got alot of projects coming fast,Pex water lines,insulating conditioned crawl space,new bath,new kitchen.I`m planning on doing it mostly by myself.I live in south carolina.


ndmick, from all my reading, research, and talking to folks on this forum the vapor barrier should be run up the foundation wall approx a few inches from the top so inspections can be done if need be down the line. When I insulated my foundation wall with rigid foam board I left 3" - "4 inches to the top of the sil plate to give me room to add foundation tape and foundation pins to secure the vapor barrier. Hope that helps and good luck!


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## ndmick (Jan 26, 2012)

Thanks ,I was just not sure if the barrier goes under the insulation or over top the rigid foam board?


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## cbaur88 (Jan 25, 2011)

ndmick said:


> Thanks ,I was just not sure if the barrier goes under the insulation or over top the rigid foam board?


From what I've read and been recommended it goes over top. Good luck :thumbsup:


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