can someone help with this problem? i have a problem with vibration in my
(spare) bedroom ceiling that i cannot stop -- finding the source is easy --
the furnace and a/c evaporator is directly overhead. As far as i can tell,
there's nothing wrong with either unit -- i suspect that when the home was
originally built (about 5 years ago) that somebody did a lousy job of
hanging the sheetrock and/or isolating the upstairs unit.

i have put in about 15 sheet rock screws but the vibration continues -- it's
wierd, if you just barely touch the ceiling the vibration will stop but give
it about 30 seconds and it'll start back...

any suggestions? should i continue with the sheetrock screws (my ceiling
looks like a gunfight broke out! ...anyone ever had this problem...


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On Sat, 28 Aug 2004 12:08:18 -0400, "Allen S."
wrote:

c i have a problem with vibration in my
(spare) bedroom ceiling that i cannot stop -- finding the source is easy --
the furnace and a/c evaporator is directly overhead. As far as i can tell,
there's nothing wrong with either unit -- i suspect that when the home was
originally built (about 5 years ago) that somebody did a lousy job of
hanging the sheetrock and/or isolating the upstairs unit.



Whatis the frequency of the vibration?
The 60 Hz house current hum?
The furnace motor vibes?
A squeal?
Rattles? from the water pipes?

The problem is related to the HVAC unit. It is a typical problem
with attic mounted units. The cure is doing something to the
unit, not adding screws to the drywall.

It should be installed on isolation pads with vibrasorber
connections to any and all duct work.

An additional solution would be to suspend the unit by all-
thread with vibration damping couplings, keeping it completely off
the ceiling framing.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing . . . .
DanG (remove the sevens)




"Allen S." wrote in message
news
can someone help with this problem? i have a problem with
vibration in my (spare) bedroom ceiling that i cannot stop --
finding the source is easy -- the furnace and a/c evaporator is
directly overhead. As far as i can tell, there's nothing wrong
with either unit -- i suspect that when the home was originally
built (about 5 years ago) that somebody did a lousy job of
hanging the sheetrock and/or isolating the upstairs unit.

i have put in about 15 sheet rock screws but the vibration
continues -- it's wierd, if you just barely touch the ceiling
the vibration will stop but give it about 30 seconds and it'll
start back...

any suggestions? should i continue with the sheetrock screws (my
ceiling looks like a gunfight broke out! ...anyone ever had
this problem...


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.744 / Virus Database: 496 - Release Date: 8/25/2004

Allen S. wrote:

...if you just barely touch the ceiling the vibration will stop but give
it about 30 seconds and it'll start back...

Can you sprinkle some sand on top of the ceiling?

Nick

hi papa -- it's not 60 Hz current home; it only occurs when the air
conditioning is cycling on -- otherwise no sound...

"PaPaPeng" wrote in message
...
On Sat, 28 Aug 2004 12:08:18 -0400, "Allen S."
wrote:

c i have a problem with vibration in my
(spare) bedroom ceiling that i cannot stop -- finding the source is
easy --
the furnace and a/c evaporator is directly overhead. As far as i can tell,
there's nothing wrong with either unit -- i suspect that when the home was
originally built (about 5 years ago) that somebody did a lousy job of
hanging the sheetrock and/or isolating the upstairs unit.



Whatis the frequency of the vibration?
The 60 Hz house current hum?
The furnace motor vibes?
A squeal?
Rattles? from the water pipes?


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.744 / Virus Database: 496 - Release Date: 8/25/2004

Dan -- thanks for this. I was wondering about this. There appears to be
absolutely no isolation in the unit now so any thing i do along those lines
should help. One thing with using the drywall screws is that I'm just
creating a more solid connection to the vibration source and that could make
things worse not better...i think you're right that isolation / dampening
may be the way to go...

"DanG" wrote in message
news:tD2Yc.13944$Ka6.4208@okepread03...
The problem is related to the HVAC unit. It is a typical problem with
attic mounted units. The cure is doing something to the unit, not adding
screws to the drywall.

It should be installed on isolation pads with vibrasorber connections to
any and all duct work.

An additional solution would be to suspend the unit by all- thread with
vibration damping couplings, keeping it completely off the ceiling
framing.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing . . . .
DanG (remove the sevens)




"Allen S." wrote in message
news
can someone help with this problem? i have a problem with vibration in my
(spare) bedroom ceiling that i cannot stop -- finding the source is
easy -- the furnace and a/c evaporator is directly overhead. As far as i
can tell, there's nothing wrong with either unit -- i suspect that when
the home was originally built (about 5 years ago) that somebody did a
lousy job of hanging the sheetrock and/or isolating the upstairs unit.

i have put in about 15 sheet rock screws but the vibration continues --
it's wierd, if you just barely touch the ceiling the vibration will stop
but give it about 30 seconds and it'll start back...

any suggestions? should i continue with the sheetrock screws (my ceiling
looks like a gunfight broke out! ...anyone ever had this problem...


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.744 / Virus Database: 496 - Release Date: 8/25/2004





---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.744 / Virus Database: 496 - Release Date: 8/25/2004

nick -- what would that do. would it show the vibration pattern or something
or are you saying it'll work like magic fairy dust and make the problem go
away...)

wrote in message
...
Allen S. wrote:

...if you just barely touch the ceiling the vibration will stop but give
it about 30 seconds and it'll start back...

Can you sprinkle some sand on top of the ceiling?

Nick



---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.744 / Virus Database: 496 - Release Date: 8/25/2004

"DanG" wrote in message
news:tD2Yc.13944$Ka6.4208@okepread03...
The problem is related to the HVAC unit. It is a typical problem
with attic mounted units. The cure is doing something to the
unit, not adding screws to the drywall.

It should be installed on isolation pads with vibrasorber
connections to any and all duct work.

An additional solution would be to suspend the unit by all-
thread with vibration damping couplings, keeping it completely off
the ceiling framing.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing . . . .
DanG (remove the sevens)




"Allen S." wrote in message
news
can someone help with this problem? i have a problem with
vibration in my (spare) bedroom ceiling that i cannot stop --
finding the source is easy -- the furnace and a/c evaporator is
directly overhead. As far as i can tell, there's nothing wrong
with either unit -- i suspect that when the home was originally
built (about 5 years ago) that somebody did a lousy job of
hanging the sheetrock and/or isolating the upstairs unit.

i have put in about 15 sheet rock screws but the vibration
continues -- it's wierd, if you just barely touch the ceiling
the vibration will stop but give it about 30 seconds and it'll
start back...

any suggestions? should i continue with the sheetrock screws (my
ceiling looks like a gunfight broke out! ...anyone ever had
this problem...


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.744 / Virus Database: 496 - Release Date: 8/25/2004


Come to think of it the air exchanger units, in each of my daughter's
houses, which run continuously 24/7 are suspended by vibration damping
straps. Also the pipes which connect it are soft and flexible. In one case
it is immediately below a bedroom and the other immediately next to a
bedroom. Never heard any complaints about noise or vibration. Granted that
an AC unit has a more powerful motor, but idea the same.

"Allen S." wrote in message
...
nick -- what would that do. would it show the vibration pattern or
something
or are you saying it'll work like magic fairy dust and make the problem go
away...)

wrote in message
...
Allen S. wrote:

...if you just barely touch the ceiling the vibration will stop but give
it about 30 seconds and it'll start back...

Can you sprinkle some sand on top of the ceiling?

Do you mean lay a bag of clean dry sand up there, on top of the ceiling
sheetrock, to dampen the vibration.
Cheap and might be worth a try?
Should certainly change the 'resonance frequency' of the ceiling which
sounds like it is acting as sound board?
After all if the vibration is that severe anything/everything in the house
that could vibrate at an annoying audible frequency could be shaking and
rattling.
Enough to keep one awake nights?
If the sandbag doesn't work as a sound dampener, use it as weight ballast
for winter driving! Winter time we have four bags of sand/gravel plus iron
weights in back of our pickup truck. Also at a pinch put some sand under the
driving wheels to get traction on ice!

Allen S. wrote:

...are you saying it'll work like magic fairy dust and make the problem go
away...)

It might simulate your "barely touching the ceiling..."

...if you just barely touch the ceiling the vibration will stop but give
it about 30 seconds and it'll start back...

Can you sprinkle some sand on top of the ceiling?

Maybe a pound or two, for damping. Not a whole 50 pound bag.

Nick

On 28-Aug-2004, "Allen S." wrote:

One thing with using the drywall screws is that I'm just
creating a more solid connection to the vibration source and that could make
things worse not better...i think you're right that isolation / dampening
may be the way to go...

That's right. In dealing with vibration isolation, the key things are to
reduce the stiffness of the connection, increase the mass of the thing
vibrating or increase the damping. Increasing the damping is actually
harder than it sounds. Getting the equipment on a soft mount is the
best first step. Increasing the mass of the ceiling is also possible -
adding sand as someone suggested. However, that isn't going to affect
the damping as another poster assumed.

If you can't change the mounting of the equipment, you could hang the
ceiling from resilient channel supports.

Mike

Terry -- i imagine that the kind of dampening you're talking about is the
best -- perfect isolation!

"Terry" wrote in message
. ..

"DanG" wrote in message
news:tD2Yc.13944$Ka6.4208@okepread03...
The problem is related to the HVAC unit. It is a typical problem
with attic mounted units. The cure is doing something to the
unit, not adding screws to the drywall.

It should be installed on isolation pads with vibrasorber
connections to any and all duct work.

An additional solution would be to suspend the unit by all-
thread with vibration damping couplings, keeping it completely off
the ceiling framing.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing . . . .
DanG (remove the sevens)




"Allen S." wrote in message
news
can someone help with this problem? i have a problem with
vibration in my (spare) bedroom ceiling that i cannot stop --
finding the source is easy -- the furnace and a/c evaporator is
directly overhead. As far as i can tell, there's nothing wrong
with either unit -- i suspect that when the home was originally
built (about 5 years ago) that somebody did a lousy job of
hanging the sheetrock and/or isolating the upstairs unit.

i have put in about 15 sheet rock screws but the vibration
continues -- it's wierd, if you just barely touch the ceiling
the vibration will stop but give it about 30 seconds and it'll
start back...

any suggestions? should i continue with the sheetrock screws (my
ceiling looks like a gunfight broke out! ...anyone ever had
this problem...


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.744 / Virus Database: 496 - Release Date: 8/25/2004


Come to think of it the air exchanger units, in each of my daughter's
houses, which run continuously 24/7 are suspended by vibration damping
straps. Also the pipes which connect it are soft and flexible. In one case
it is immediately below a bedroom and the other immediately next to a
bedroom. Never heard any complaints about noise or vibration. Granted that
an AC unit has a more powerful motor, but idea the same.


Terry -- i imagine that the kind of dampening you're talking about is the
best -- perfect isolation!

"Terry" wrote in message
. ..

"DanG" wrote in message
news:tD2Yc.13944$Ka6.4208@okepread03...
The problem is related to the HVAC unit. It is a typical problem
with attic mounted units. The cure is doing something to the
unit, not adding screws to the drywall.

It should be installed on isolation pads with vibrasorber
connections to any and all duct work.

An additional solution would be to suspend the unit by all-
thread with vibration damping couplings, keeping it completely off
the ceiling framing.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Keep the whole world singing . . . .
DanG (remove the sevens)




"Allen S." wrote in message
news
can someone help with this problem? i have a problem with
vibration in my (spare) bedroom ceiling that i cannot stop --
finding the source is easy -- the furnace and a/c evaporator is
directly overhead. As far as i can tell, there's nothing wrong
with either unit -- i suspect that when the home was originally
built (about 5 years ago) that somebody did a lousy job of
hanging the sheetrock and/or isolating the upstairs unit.

i have put in about 15 sheet rock screws but the vibration
continues -- it's wierd, if you just barely touch the ceiling
the vibration will stop but give it about 30 seconds and it'll
start back...

any suggestions? should i continue with the sheetrock screws (my
ceiling looks like a gunfight broke out! ...anyone ever had
this problem...


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.744 / Virus Database: 496 - Release Date: 8/25/2004


Come to think of it the air exchanger units, in each of my daughter's
houses, which run continuously 24/7 are suspended by vibration damping
straps. Also the pipes which connect it are soft and flexible. In one case
it is immediately below a bedroom and the other immediately next to a
bedroom. Never heard any complaints about noise or vibration. Granted that
an AC unit has a more powerful motor, but idea the same.

i may give that a shot -- i already moved some heavy stuff next to the unit
but it didn't stop the problem...


"Terry" wrote in message
. ..

"Allen S." wrote in message
...
nick -- what would that do. would it show the vibration pattern or
something
or are you saying it'll work like magic fairy dust and make the problem
go
away...)

wrote in message
...
Allen S. wrote:

...if you just barely touch the ceiling the vibration will stop but
give
it about 30 seconds and it'll start back...

Can you sprinkle some sand on top of the ceiling?

Do you mean lay a bag of clean dry sand up there, on top of the ceiling
sheetrock, to dampen the vibration.
Cheap and might be worth a try?
Should certainly change the 'resonance frequency' of the ceiling which
sounds like it is acting as sound board?
After all if the vibration is that severe anything/everything in the house
that could vibrate at an annoying audible frequency could be shaking and
rattling.
Enough to keep one awake nights?
If the sandbag doesn't work as a sound dampener, use it as weight ballast
for winter driving! Winter time we have four bags of sand/gravel plus iron
weights in back of our pickup truck. Also at a pinch put some sand under
the
driving wheels to get traction on ice!




---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.744 / Virus Database: 496 - Release Date: 8/25/2004

thanks for the suggestion Nick.

wrote in message
...
Allen S. wrote:

...are you saying it'll work like magic fairy dust and make the problem go
away...)

It might simulate your "barely touching the ceiling..."

...if you just barely touch the ceiling the vibration will stop but give
it about 30 seconds and it'll start back...

Can you sprinkle some sand on top of the ceiling?

Maybe a pound or two, for damping. Not a whole 50 pound bag.

Nick



---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
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the isolation pads appear to be really cheap but it doesn't seem like a very
good do-it-yourself job -- it's such a frustrating problem! i've seen pads
on the internet for this purpose at about $1.50 for an 8 inch square
pad...if i'm not mistaken...


"Michael Daly" wrote in message
...
On 28-Aug-2004, "Allen S." wrote:

One thing with using the drywall screws is that I'm just
creating a more solid connection to the vibration source and that could
make
things worse not better...i think you're right that isolation / dampening
may be the way to go...

That's right. In dealing with vibration isolation, the key things are to
reduce the stiffness of the connection, increase the mass of the thing
vibrating or increase the damping. Increasing the damping is actually
harder than it sounds. Getting the equipment on a soft mount is the
best first step. Increasing the mass of the ceiling is also possible -
adding sand as someone suggested. However, that isn't going to affect
the damping as another poster assumed.

If you can't change the mounting of the equipment, you could hang the
ceiling from resilient channel supports.

Mike


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.744 / Virus Database: 496 - Release Date: 8/25/2004

Allen S. wrote:

thanks for the suggestion Nick.

You are welcome. I wouldn't have suggested it if you hadn't mentioned that
barely touching the ceiling killed the vibration. I've simulated fingers in
electronic design. If you want to dampen, don't use frictionless sand :-)

Nick