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?

1. yes
2. One
3. yes

:)

Need to have a return.

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?????

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

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

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

Who had wrong:huh:

You had wrong you mean?

Nope. My answer is correct.

Dmnit..which one?

The one about just adding a supply without a return.

..and you agreed with me.

Simply answered 1 question.

Glad you concur:thumbsup:

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!