TT

"Tim Taylor"

31/07/2006 10:03 PM

plenum

Anybody ever heard of or done an HVAC plenum in plywood? Would/could it
work???



This topic has 15 replies

GS

George Shouse

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

31/07/2006 10:51 PM

On Mon, 31 Jul 2006 22:03:50 -0400, "Tim Taylor"
<[email protected]> wrote:

>Anybody ever heard of or done an HVAC plenum in plywood? Would/could it
>work???

Why? Constant hot air flow & THIN wood?

FB

Frank Boettcher

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 4:20 PM

On Tue, 1 Aug 2006 08:50:13 -0400, "Tim Taylor" <[email protected]>
wrote:

>
>"R. Pierce Butler" <[email protected]> wrote in message
>news:[email protected]...
>> "Tim Taylor" <[email protected]> wrote in
>> news:_OOdnT4PS50YK1PZnZ2dnUVZ_t-
>> [email protected]:
>>
>>> Anybody ever heard of or done an HVAC plenum in plywood? Would/could it
>>> work???
>>>
>>>
>>>
>>
>> For AC it might work. For heat? Forget it.
>>
>
>Yea, that's what I was talking about, just air. He's got electric heat. It's
>just in a garage, and was tossing around the idea of just a plenum box and
>about 20 feet of ductwork to say. It would be at the back of the garage on
>the ceiling just something to distribute the air a little more evenly. Metal
>is no big deal, but he's got about 50 sheets of plywood laying around and
>was just asking me. I don't have a clue as I did mine in metal since it's
>heat and air. That's why I wanted to ask here. Didn't mean to get the code
>police after me and to ruffle any feathers.
>


If it is just for distribution and the duct is in the conditioned air
area, that is, it is not going through your attic or other
unconditioned area it would be fine.

My kitchen uses the soffit above the cabinets for distribution only,
with three registers. But it is in the insulated, conditioned air
area, so it works just fine. it is fed from the attic area by
insulated metal duct.

Frank

RM

"Ron Magen"

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 3:38 PM

Tim,

Read the 'answers' to date . . . a lot of validity . . . HOWEVER . . .

Half of my basement is finished {NO - I didn't do it - crappy idea and
crappy work}and the duct from the heater is 'covered' {boxed in}with the
wood paneling. When we bought the house it was gas-fired hot-air HEAT ONLY.
Later we replaced the old heater with a newer Heat & AC unit.

I am now in the process of 're-furbishing' out up-stairs bathroom. While the
'air out' grill is about a 4 x 11 inch rectangle, the ducting that feeds it
seems to be a 4in circular 'pipe'. For I don't know how many reasons
{'paranoid' being one}, I wouldn't want a 'hot air' duct of thin wood ONLY.
Some 'el cheapo' insulated 'Dryer Duct' - even the flexible kind - would do
for the actual 'transfer conduit'. It could then be 'disguised or
'supported' by the plywood.

Regards & Good Luck,
Ron Magen
backyard Boatshop

"Tim Taylor" <[email protected]> wrote in message
news:[email protected]...
> Anybody ever heard of or done an HVAC plenum in plywood? Would/could it
> work???
>
>
>

Bn

"BobS"

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 2:46 PM

Tim,

Something your friend may want to consider is the possibility of mold
growing on the inside of that plenum. Unless it's coated, the wood will
absorb moisture and he will have the potential for some bad mold problems.

Bob S.


"Tim Taylor" <[email protected]> wrote in message
news:[email protected]...
>
> "R. Pierce Butler" <[email protected]> wrote in message
> news:[email protected]...
>> "Tim Taylor" <[email protected]> wrote in
>> news:_OOdnT4PS50YK1PZnZ2dnUVZ_t-
>> [email protected]:
>>
>>> Anybody ever heard of or done an HVAC plenum in plywood? Would/could it
>>> work???
>>>
>>>
>>>
>>
>> For AC it might work. For heat? Forget it.
>>
>
> Yea, that's what I was talking about, just air. He's got electric heat.
> It's just in a garage, and was tossing around the idea of just a plenum
> box and about 20 feet of ductwork to say. It would be at the back of the
> garage on the ceiling just something to distribute the air a little more
> evenly. Metal is no big deal, but he's got about 50 sheets of plywood
> laying around and was just asking me. I don't have a clue as I did mine in
> metal since it's heat and air. That's why I wanted to ask here. Didn't
> mean to get the code police after me and to ruffle any feathers.
>

TT

"Tim Taylor"

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 11:36 AM


"BobS" <[email protected]> wrote in message
news:[email protected]...
> Tim,
>
> Something your friend may want to consider is the possibility of mold
> growing on the inside of that plenum. Unless it's coated, the wood will
> absorb moisture and he will have the potential for some bad mold problems.
>
> Bob S.
>
Bob, you know that's something I never thought of!! That's why I wanted some
others thoughts on the matter. It's like looking for something dropped in
the grass, extra pairs of eyes are always helpful! Thanks so much!!! And
thanks everybody else!! Metal it'll be.

sD

[email protected] (Doug Miller)

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 2:38 AM

In article <[email protected]>, "Tim Taylor" <[email protected]> wrote:
>Anybody ever heard of or done an HVAC plenum in plywood? Would/could it
>work???

I can't even begin to imagine that it would meet fire-safety codes...

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

RP

"R. Pierce Butler"

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 7:09 AM

"Tim Taylor" <[email protected]> wrote in news:_OOdnT4PS50YK1PZnZ2dnUVZ_t-
[email protected]:

> Anybody ever heard of or done an HVAC plenum in plywood? Would/could it
> work???
>
>
>

For AC it might work. For heat? Forget it.

RP

"R. Pierce Butler"

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 5:21 PM

"Tim Taylor" <[email protected]> wrote in
news:[email protected]:

>
> "BobS" <[email protected]> wrote in message
> news:[email protected]...
>> Tim,
>>
>> Something your friend may want to consider is the possibility of mold
>> growing on the inside of that plenum. Unless it's coated, the wood
>> will absorb moisture and he will have the potential for some bad mold
>> problems.
>>
>> Bob S.
>>
> Bob, you know that's something I never thought of!! That's why I wanted
> some others thoughts on the matter. It's like looking for something
> dropped in the grass, extra pairs of eyes are always helpful! Thanks so
> much!!! And thanks everybody else!! Metal it'll be.
>
>
>

I can't see where moisture or mold would be a problem. The air is dry,
cold, and that alone should keep things free of mold. I would not hesitate
to use plywood as a AC only plenum. I might paint or some other water
based coating for the inside but that is just to keep things clean on the
inside.


On the plus side you don't need to insulate the plenum as much (if at all)
if it is made of plywood.

Pg

Patriarch

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 2:34 PM

"R. Pierce Butler" <[email protected]> wrote in
news:[email protected]:

<snip>

> I can't see where moisture or mold would be a problem. The air is
> dry, cold, and that alone should keep things free of mold. I would
> not hesitate to use plywood as a AC only plenum. I might paint or
> some other water based coating for the inside but that is just to keep
> things clean on the inside.
>

You don't think that there would be any condensation issues?

Molds seem to grow easily in many systems, if the HVAC folks are telling
any truths...

Patriarch,
thinking the metal isn't terribly expensive...

Pg

Patriarch

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 5:19 PM

"R. Pierce Butler" <[email protected]> wrote in
news:[email protected]:

> Patriarch <[email protected]> wrote in
> news:[email protected]:
>
>> "R. Pierce Butler" <[email protected]> wrote in
>> news:[email protected]:
>>
>> <snip>
>>
>>> I can't see where moisture or mold would be a problem. The air is
>>> dry, cold, and that alone should keep things free of mold. I would
>>> not hesitate to use plywood as a AC only plenum. I might paint or
>>> some other water based coating for the inside but that is just to
>>> keep things clean on the inside.
>>>
>>
>> You don't think that there would be any condensation issues?
>>
>> Molds seem to grow easily in many systems, if the HVAC folks are
>> telling any truths...
>>
>> Patriarch,
>> thinking the metal isn't terribly expensive...
>>
>
> Metal is not cheap. Have you seen the price of copper lately? Go
> check out copper wire at HD or Lowes.
>
> When I put a furnace in my house it cost as much for the ductwork as
> it did for the furnace and the furnace was very expensive. I did all
> the labor installing the ductwork and furnace.
>
> Condensation? There shouldn't be any. If you get condensation with
> wood then the condensation with metal would be worse. Wood is an
> insulator and metal a conductor.
>
>

The duct tubing in my CALIFORNIA home is aluminum, or galvanized steel.
An insulating blanket is wrapped around it.

I realize that we're different here in the Bay Area, and folks do things
their own way elsewhere. Copper, though, would be pretty 'special'.
The local newsies have run stories about lowlifes stealing copper from
construction sites for the recycling cash. And some fool tries to strip
a power junction box, getting partway before something struck him...

Nope. No copper here. YMMV.

Patriarch

RP

"R. Pierce Butler"

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 10:02 PM

Patriarch <[email protected]> wrote in
news:[email protected]:

> "R. Pierce Butler" <[email protected]> wrote in
> news:[email protected]:
>
> <snip>
>
>> I can't see where moisture or mold would be a problem. The air is
>> dry, cold, and that alone should keep things free of mold. I would
>> not hesitate to use plywood as a AC only plenum. I might paint or
>> some other water based coating for the inside but that is just to keep
>> things clean on the inside.
>>
>
> You don't think that there would be any condensation issues?
>
> Molds seem to grow easily in many systems, if the HVAC folks are telling
> any truths...
>
> Patriarch,
> thinking the metal isn't terribly expensive...
>

Metal is not cheap. Have you seen the price of copper lately? Go check
out copper wire at HD or Lowes.

When I put a furnace in my house it cost as much for the ductwork as it did
for the furnace and the furnace was very expensive. I did all the labor
installing the ductwork and furnace.

Condensation? There shouldn't be any. If you get condensation with wood
then the condensation with metal would be worse. Wood is an insulator and
metal a conductor.

RP

"R. Pierce Butler"

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 11:34 PM

Patriarch <[email protected]> wrote in
news:[email protected]:

> "R. Pierce Butler" <[email protected]> wrote in
> news:[email protected]:
>
>> Patriarch <[email protected]> wrote in
>> news:[email protected]:
>>
>>> "R. Pierce Butler" <[email protected]> wrote in
>>> news:[email protected]:
>>>
>>> <snip>
>>>
>>>> I can't see where moisture or mold would be a problem. The air is
>>>> dry, cold, and that alone should keep things free of mold. I would
>>>> not hesitate to use plywood as a AC only plenum. I might paint or
>>>> some other water based coating for the inside but that is just to
>>>> keep things clean on the inside.
>>>>
>>>
>>> You don't think that there would be any condensation issues?
>>>
>>> Molds seem to grow easily in many systems, if the HVAC folks are
>>> telling any truths...
>>>
>>> Patriarch,
>>> thinking the metal isn't terribly expensive...
>>>
>>
>> Metal is not cheap. Have you seen the price of copper lately? Go
>> check out copper wire at HD or Lowes.
>>
>> When I put a furnace in my house it cost as much for the ductwork as
>> it did for the furnace and the furnace was very expensive. I did all
>> the labor installing the ductwork and furnace.
>>
>> Condensation? There shouldn't be any. If you get condensation with
>> wood then the condensation with metal would be worse. Wood is an
>> insulator and metal a conductor.
>>
>>
>
> The duct tubing in my CALIFORNIA home is aluminum, or galvanized steel.
> An insulating blanket is wrapped around it.
>
> I realize that we're different here in the Bay Area, and folks do things
> their own way elsewhere. Copper, though, would be pretty 'special'.
> The local newsies have run stories about lowlifes stealing copper from
> construction sites for the recycling cash. And some fool tries to strip
> a power junction box, getting partway before something struck him...
>
> Nope. No copper here. YMMV.
>
> Patriarch
>

all metals have gone up in price. Copper is 4 times what it used to be a
year or so ago. Aluminum, zinc, steel and more have had increases too. I
looked at some copper tubing at Lowes two weeks ago. It was close to $5.00
per foot! A machinist across town told me that alumunim has had similar
increases. Steel and zinc and the rest are starting to go up too.

TT

"Tim Taylor"

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 11:49 AM


"Ron Magen" <[email protected]> wrote in message
news:BzKzg.4713$zV6.4427@trnddc03...
> Tim,
>
> Read the 'answers' to date . . . a lot of validity . . . HOWEVER . . .
>
> Half of my basement is finished {NO - I didn't do it - crappy idea and
> crappy work}and the duct from the heater is 'covered' {boxed in}with the
> wood paneling. When we bought the house it was gas-fired hot-air HEAT
> ONLY.
> Later we replaced the old heater with a newer Heat & AC unit.
>
> I am now in the process of 're-furbishing' out up-stairs bathroom. While
> the
> 'air out' grill is about a 4 x 11 inch rectangle, the ducting that feeds
> it
> seems to be a 4in circular 'pipe'. For I don't know how many reasons
> {'paranoid' being one}, I wouldn't want a 'hot air' duct of thin wood
> ONLY.
> Some 'el cheapo' insulated 'Dryer Duct' - even the flexible kind - would
> do
> for the actual 'transfer conduit'. It could then be 'disguised or
> 'supported' by the plywood.
>
> Regards & Good Luck,
> Ron Magen
> backyard Boatshop
>

Thanks Ron. As I said, it's air only and in a garage and he has a ton of
plywood laying around. That's why we even thought of it. The thing is just
blowing straight out of the a-coil now hitting the ceiling and dispersing
air real random. I think that everyone has talked me out of doing it in
wood, mold being the biggest reason. And if he wants to cover the metal duct
with it, then he can have fun doing and get rid of some of the ply too.
It'll just be the width of the garage with a half dozen or so vents pointed
out to the working area, no other ducting would be needed. Thanks for the
tip!

> "Tim Taylor" <[email protected]> wrote in message
> news:[email protected]...
>> Anybody ever heard of or done an HVAC plenum in plywood? Would/could it
>> work???
>>
>>
>>
>
>

MB

M Berger

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 9:20 AM

The air return in my old house was hardboard nailed between
floor joists. Plywood should be fine for A/C or return.

Tim Taylor wrote:
> Anybody ever heard of or done an HVAC plenum in plywood? Would/could it
> work???
>
>
>

TT

"Tim Taylor"

in reply to "Tim Taylor" on 31/07/2006 10:03 PM

01/08/2006 8:50 AM


"R. Pierce Butler" <[email protected]> wrote in message
news:[email protected]...
> "Tim Taylor" <[email protected]> wrote in
> news:_OOdnT4PS50YK1PZnZ2dnUVZ_t-
> [email protected]:
>
>> Anybody ever heard of or done an HVAC plenum in plywood? Would/could it
>> work???
>>
>>
>>
>
> For AC it might work. For heat? Forget it.
>

Yea, that's what I was talking about, just air. He's got electric heat. It's
just in a garage, and was tossing around the idea of just a plenum box and
about 20 feet of ductwork to say. It would be at the back of the garage on
the ceiling just something to distribute the air a little more evenly. Metal
is no big deal, but he's got about 50 sheets of plywood laying around and
was just asking me. I don't have a clue as I did mine in metal since it's
heat and air. That's why I wanted to ask here. Didn't mean to get the code
police after me and to ruffle any feathers.


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