Is it OK to bury AC ductwork in a crawlspace? I need to do some repairs
on my ducts because my crawlspace is very narrow (maybe 18-20 inches
from dirt to joist in most areas), and the ducts have been beaten up
over the years by people scraping over them to get from one place to
another.

I was thinking that if, when I replaced the damaged duct, I made a
trench in the dirt, lined it with 18mil Visqueen, and put a piece of
plywood on top of that, I could both open the crawlspace up some, and
lessen the chances of the ducting getting clobbered again.

Has anyone here done such a thing, or am I about to undertake a task
fraught with danger and unnecessary expense?

"nhurst" wrote in message
oups.com...
Is it OK to bury AC ductwork in a crawlspace? I need to do some repairs
on my ducts because my crawlspace is very narrow (maybe 18-20 inches
from dirt to joist in most areas), and the ducts have been beaten up
over the years by people scraping over them to get from one place to
another.

I was thinking that if, when I replaced the damaged duct, I made a
trench in the dirt, lined it with 18mil Visqueen, and put a piece of
plywood on top of that, I could both open the crawlspace up some, and
lessen the chances of the ducting getting clobbered again.

Has anyone here done such a thing, or am I about to undertake a task
fraught with danger and unnecessary expense?


What are people doing in the crawlspace to begin with, which leads them to
damaging the ducts?

Home inspection is the most recent. We've also had pest control folks
under there since we bought the house. Before we bought there were
telephone guys, plumbers, cable guys, and electricians.

I've been moving everything I can (like telephone, cable, and some
electrical) up to the attic, but I'm still going to want to get around
under the house so I can check for problems.

The people under the house haven't been careless, there's just
literally no room to get by without scraping past a duct. I've got
water pipes going all over the place as well, and that's an added
headache when they cross over a duct.

Sounds like an old house with lots of patch work connections.
I know duct gets buried on some slab-on-grade projects, but I don't
like it.
I've a similar situation and suggest you look at running the ducts
above the ceiling.
Major change, but better for the ducts and for maintenance.
TB

"nhurst" wrote in message
oups.com...
Is it OK to bury AC ductwork in a crawlspace? I need to do some repairs
on my ducts because my crawlspace is very narrow (maybe 18-20 inches
from dirt to joist in most areas), and the ducts have been beaten up
over the years by people scraping over them to get from one place to
another.

I was thinking that if, when I replaced the damaged duct, I made a
trench in the dirt, lined it with 18mil Visqueen, and put a piece of
plywood on top of that, I could both open the crawlspace up some, and
lessen the chances of the ducting getting clobbered again.

Has anyone here done such a thing, or am I about to undertake a task
fraught with danger and unnecessary expense?


I think you'd be better off building some sort of wooden fence type of thing
to protect the ducts. Could be as simple as frames which run alongside the
ducts, strung with chicken wire, just far enough from the ducts to keep
tools & feet from touching the ducts. Use lag bolts to hang them from the
rafters, and you can remove them easily if necessary, using a ratchet
attachment on a drill.

I've a similar situation and suggest you look at running the ducts above the ceiling.
Major change, but better for the ducts and for maintenance.

We thought about this, but the major problem with this is that our
attic is small as well. The house was built without air conditioning in
1960, only a furnace. If we were to put the ducting in the attic, we
wouldn't be able to do anything up there.

-Nathan

nhurst wrote:
Is it OK to bury AC ductwork in a crawlspace? I need to do some
repairs on my ducts because my crawlspace is very narrow (maybe 18-20
inches from dirt to joist in most areas), and the ducts have been
beaten up over the years by people scraping over them to get from one
place to another.

I was thinking that if, when I replaced the damaged duct, I made a
trench in the dirt, lined it with 18mil Visqueen, and put a piece of
plywood on top of that, I could both open the crawlspace up some, and
lessen the chances of the ducting getting clobbered again.

Has anyone here done such a thing, or am I about to undertake a task
fraught with danger and unnecessary expense?

Well if you burry them they will likely be better insulated, but it is
going to be a lot of work to do that in an area with that little access. I
would bet that in the long run, it will be far easier not to do it.

--
Joseph Meehan

Dia duit

On 20 Jan 2006 04:40:50 -0800, "nhurst" wrote:

Is it OK to bury AC ductwork in a crawlspace? I need to do some repairs
on my ducts because my crawlspace is very narrow (maybe 18-20 inches
from dirt to joist in most areas), and the ducts have been beaten up
over the years by people scraping over them to get from one place to
another.

I was thinking that if, when I replaced the damaged duct, I made a
trench in the dirt, lined it with 18mil Visqueen, and put a piece of
plywood on top of that, I could both open the crawlspace up some, and
lessen the chances of the ducting getting clobbered again.

Has anyone here done such a thing, or am I about to undertake a task
fraught with danger and unnecessary expense?


When I lived in Tulsa, it was a common practice at that time to put
the ducts underground, however they were encased in concrete below a
slab. The ducts were set and poured in when the curbwall was put in
place and then a slab was poured over them. Good point is good
insulation. Bad thing is that occaisonally a water supply pipe would
break and invariably the water would permeate and collect in the duct.
You would find out when the humidity went way up in the house.

I think it would work if you can keep the water out.

"Frank Boettcher" wrote in message
...
On 20 Jan 2006 04:40:50 -0800, "nhurst" wrote:

Is it OK to bury AC ductwork in a crawlspace? I need to do some repairs
on my ducts because my crawlspace is very narrow (maybe 18-20 inches
from dirt to joist in most areas), and the ducts have been beaten up
over the years by people scraping over them to get from one place to
another.

I was thinking that if, when I replaced the damaged duct, I made a
trench in the dirt, lined it with 18mil Visqueen, and put a piece of
plywood on top of that, I could both open the crawlspace up some, and
lessen the chances of the ducting getting clobbered again.

Has anyone here done such a thing, or am I about to undertake a task
fraught with danger and unnecessary expense?


When I lived in Tulsa, it was a common practice at that time to put
the ducts underground, however they were encased in concrete below a
slab. The ducts were set and poured in when the curbwall was put in
place and then a slab was poured over them. Good point is good
insulation. Bad thing is that occaisonally a water supply pipe would
break and invariably the water would permeate and collect in the duct.
You would find out when the humidity went way up in the house.

I think it would work if you can keep the water out.

He didn't mention the size or shape of his ducts (or I missed it). If
they're the large-ish rectangular ones like mine, he's gonna have a hell of
a time trying to dig trenches for them with the limited movement available
in a crawl space. On the other hand, people *did* manage to dig tunnels out
of prison camps under worse conditions.

He didn't mention the size or shape of his ducts (or I missed it)

They're 6 inch round ducts. When you add the insulation to that,
they're about 8 inches total across.

Someone I asked locally mentioned that mold might become an issue. Does
anyone here have any thoughts on that?

"nhurst" wrote in message
ups.com...
He didn't mention the size or shape of his ducts (or I missed it)

They're 6 inch round ducts. When you add the insulation to that,
they're about 8 inches total across.

Someone I asked locally mentioned that mold might become an issue. Does
anyone here have any thoughts on that?


Well, those ducts aren't exactly sealed at the joints. So, more than mold,
I'd wonder about water getting into them if you had odd weather and the
ground got soaked.

I had planned to wrap them in something like Visqueen or perhaps
something like a tube similar to what a newspaper comes in. I figure
with no sunlight hitting it, it should last a good long time.

There are companies that make plastic ducts for use underground.
Anything not waterproof wouyld be a mistake.

Stretch

Try This for underground ducts:

www.foremostduct.com

Stretch