Old house. Part basement, part crawlspace. There are heat and cold
air boxes in the floor over the crawlspace. The (round) ducts for
these pass through (very) rough openings knocked through the
(limestone?) foundation wall of the basement.
Right now, I have insulation stuffed around the ducts, to close the
openings. (The crawlspace is cold, unconditioned.)
There's probably a better way to do that? I'm thinking to block it in
as best I can with masonry, and fill the rest with ...?
If it is always dry. If moisture is present at times, like rainy summer,
sealing floor is bad idea? My cabin has crawl space. Gas furnace and
electric WH are located there. Skirting walls are insulated with R20
fiberglass rolls and vapor barrier. Ceiling(floor of living space above
is done same way) Crawl space is very warm even in dead winter. Maybe
use spray foam?
On 2/26/2015 2:34 PM, firstname.lastname@example.org wrote:
Great Stuff expanding foam comes to mind. At hardware
store, and also Walmart in the paint section.
Some advice is needed, before using the stuff.....
Christopher A. Young
learn more about Jesus
On Thursday, February 26, 2015 at 5:47:54 PM UTC-5, Stormin Mormon wrote:
That's what I was thinking too for the stated purpose. But there
are other possible issues, eg are the ducts insulated in the cold
crawl space, floor insulated, etc. If not, the holes the ducts
pass through may not be the biggest issue, having some fiberglass
in them already.
Are there any water lines in the crawl space area? If so, keeping some
opening between the crawl space and the basement may allow enough warm air
from the basement to enter the crawl space to keep the water pipes from
Just for completeness, I had considered the areosol foam - at least
assuming everyone is talking about "Great Stuff' type things. The
concern I had with that is that the way the ducts are positioned (eg,
a 10" and a 6" pipe roughly on a 45-degree axis), the 'corners' would
take a lot of fill. I've gotten the impression that that foam isn't
really meant for filling large volumes - it needs air/moisture to
On further thought, I think I'll block it in as much as I can, and
then back the corners gaps with wire lath, and use that as a base for
layering the foam. It's just a lot of effort. I don't know what I
was expecting - magic, I guess. Oh well.
Thanks for all the replies.
On Saturday, February 28, 2015 at 6:20:21 AM UTC-5, email@example.com wrote:
If it's large, you don't have to fill the large parts all at once.
You can do it in a couple stages. But unless it's really huge,
I don't think you have much to worry about. If it's cement block,
there will be enough air movement that it will cure. Seems to me
it would also be easy to fill any of the larger parts with some
insulation, anything that you can stuff in there easy. Wire lath
wouldn't be my first choice.
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