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-   -   Encapsulating & Conditioning Crawlspace -- Adding Supply Vents (http://www.diychatroom.com/f17/encapsulating-conditioning-crawlspace-adding-supply-vents-137282/)

BadgerVA 03-16-2012 10:04 PM

Encapsulating & Conditioning Crawlspace -- Adding Supply Vents
 
This is my first post here, so bear with me if I miss something, but am hoping for advice as I encapsulate my crawlspace.

I've done a lot of reading here and elsewhere and plan to encapsulate my crawlspace in my split level home in Northern VA. The crawl space is about 700 sq. ft in area by 3 feet in height (to the top of the walls, not including rafters). There are two external vents that I plan to close and when I do so, I would like to add conditioned air to the crawlspace. Also, the floor is loose poured concrete and walls are block and testing for radon had no concerning readings. I plan to eventually insulate the walls and potentially add a vapor barrier, but there is no water issues, so I'm not in a rush there.

I have one large supply duct (but no return) that supplies heating/cooling to the main floor above. It would be fairly easy to add a vent or two to the main trunk here. My questions include the following:

A) Can I just add a supply vent without a return?
B) How many supply vents should I add?
C) Should I include a backdraft damper to the supply vent?

Thanks and let me know if there are other things I should be considering?

CrawlSpaceMoist 03-17-2012 10:05 AM

1. yes
2. One
3. yes

:)

beenthere 03-17-2012 11:08 AM

Need to have a return.

hvac5646 03-17-2012 11:24 AM

I would agree on GPabout the return, as all condtioned spaces require them, but this is an un-occupied space.

And why, Been, did you not make mention of the the fact that the main duct has no return in the occupied space it serves?

And furthermore, Beenthere, how do you justify adding a few supplies opening to the crawl with out knowing the size of the supply duct or the air flow it's providing?????

beenthere 03-17-2012 11:31 AM

Quote:

Originally Posted by hvac5646 (Post 879481)
I would agree on GPabout the return, as all condtioned spaces require them, but this is an un-occupied space.

And why, Been, did you not make mention of the the fact that the main duct has no return in the occupied space it serves?

Its getting its return from another area open to the main area.

And furthermore, Beenthere, how do you justify adding a few supplies opening to the crawl with out knowing the size of the supply duct or the air flow it's providing?????

Never said anything about adding supplies to that duct. Only said it will need return.

hvac5646 03-17-2012 11:34 AM

But by omitting the supplies from your answer your are endorsing them by omission.

beenthere 03-17-2012 11:36 AM

I simply answered the question that the previous posted has wrong.

hvac5646 03-17-2012 11:38 AM

Who had wrong:huh:

You had wrong you mean?

beenthere 03-17-2012 11:40 AM

Quote:

Originally Posted by hvac5646 (Post 879492)
Who had wrong:huh:

You had wrong you mean?

Nope. My answer is correct.

hvac5646 03-17-2012 11:48 AM

Dmnit..which one?

beenthere 03-17-2012 11:50 AM

The one about just adding a supply without a return.

hvac5646 03-17-2012 12:00 PM

..and you agreed with me.

beenthere 03-17-2012 12:02 PM

Quote:

Originally Posted by hvac5646 (Post 879509)
..and you agreed with me.

Simply answered 1 question.

hvac5646 03-17-2012 01:13 PM

Glad you concur:thumbsup:

BadgerVA 03-18-2012 07:52 AM

Now slightly confused
 
Ok, thanks for the lively "debate" :eek: -- but I'm now somewhat confused.

As I understand...

1) I SHOULD add a vent; and only 1 vent for the size of my crawlspace
2) I DO NOT need a return as this is an unoccupied space and it will slowly pull air from the surrounding space (through crawl space door, through seams/gaps naturally occurring in flooring above, etc)
3) I SHOULD use a backdraft damper when adding the supply

Can you all confirm this is the right interpretation of the input? Thanks!


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