Hi,

Various mags have some new products to use on floor and between wall and
insulation to help basement not trap moisture. I suppose by nature, some
moisture is there because the basement wall is under ground.

Are these new products hype, or do they provide some serious improvement?

Anyone have experience with these new products or ideas of their own on some
of the not seen prep work which must go on before you re-finish the
basement?

Thanks.

J

j wrote:
Hi,

Various mags have some new products to use on floor and between wall
and insulation to help basement not trap moisture. I suppose by
nature, some moisture is there because the basement wall is under
ground.

Are these new products hype, or do they provide some serious
improvement?

Anyone have experience with these new products or ideas of their own
on some of the not seen prep work which must go on before you
re-finish the basement?

Thanks.

J

Nothing new there. It is an attempt to keep moisture from coming into
the basement AFTER it already has come through the wall or floor.

In some cases it may work, but it is going to trap that moisture on the
other side of the barrier and in many cases it will not help at all. It all
depends on your problem.

Sorry but most of the time the only fix is to keep the water away from
your foundation in the first place and second to provide additional
ventilation or dehumidifiers.

--
Joseph Meehan

Dia duit

Joseph Meehan wrote:

...most of the time the only fix is to keep the water away from
your foundation in the first place and second to provide additional
ventilation or dehumidifiers.

The problem may be too much uncontrolled ventilation, esp in an older home
with lots of air leaks or a slab with no vapor barrier.

Basement exhaust with a differential humidistat (a Smart Vent?) can use
100X less electrical energy than a dehumidifier, climate permitting. My
hunch is that most do. A Key West house with no AC might be one exception.

Smart Vent's 12/19/2000 US patent no. 6,161,763 "Module-controlled building
drying system and process" at http://www.freepatentsonline.com describes
a controller connected to indoor and outdoor absolute humidity sensors.
If outdoor air has a lower absolute humidity than indoor air, the controller
turns on a ventilation fan. If outdoor air has higher absolute humidity
than indoor air, it turns the fan off.

Oddly enough, this patent measures "absolute humidity" in grams/m^3 vs
a humidity ratio in g/g, so it looks like the controller would turn on
the fan with outdoor air at 95 F and 17.4 g/m^3 and indoor air at 80 F
and 17.5 g/m^3, even though cooling 1 m^3 of the 95 F air would lower its
volume to (460+80)/(460+95) = 0.973 m^3 and raise the absolute humidity
to 17.4/0.973 = 17.9 g/m^3, so this would add moisture to a house.

As an alternative to "absolute humidity sensors" or calculations,
we might mount an RH sensor on each side of a single pane window or
a steel plate and insulate the plate indoors, except near the sensor,
and turn on the fan when outdoor RH is less than indoor RH.

Nick

wrote:
Joseph Meehan wrote:

...most of the time the only fix is to keep the water away from
your foundation in the first place and second to provide additional
ventilation or dehumidifiers.

The problem may be too much uncontrolled ventilation, esp in an older
home with lots of air leaks or a slab with no vapor barrier.


True, while less likely in my experience it is certainly possible and
should be considered.

--
Joseph Meehan

Dia duit

Joseph Meehan wrote:

...most of the time the only fix is to keep the water away from
your foundation in the first place and second to provide additional
ventilation or dehumidifiers.

The problem may be too much uncontrolled ventilation, esp in an older
home with lots of air leaks or a slab with no vapor barrier.

True, while less likely in my experience it is certainly possible...

This came from a Humidex installer who said they help more with older houses.

Nick

Nick, you scare me.

Move to South Carolina and try your idea here. Then after your house
rots down, you can move back up north.

It does not matter what the RH differaece is unless the temperature is
the same when you ventilate. If the humidity ratio(in grains of water
per pound of dry air) is higher outside than it is inside, you DO NOT
want to ventillate! If the humidity ratio is lower outside than
inside, then ventilating MAY do the trick. Either way, you MUST be
sure that the surface temperatures in the basement are ABOVE the dew
point of the air present. If the air outside is dryer than the air
inside, but the wall temperatures in the basement is still below the
outside air dew point, ventillation WILL NOT HELP!!!!!!!!!

A dehumidifier will use more electricity, but is not likely to damage
anything. Using fans with an improper control system can rot the walls
out!!! The cost of repairing the walls will be MUCH HIGHER than the
cost of the electricity saved!

In order to determine the proper fix for the OP problem, I would want
to check the weathe data for his area, measure the wall temperatures
over time with data loggers and measure the humidity inside and outside
over time with data loggers. He will be safe, if a littel poorer with
a dehumidifier, assuming he drains it outside or into a proper drain.
Using your RH sensor scheme may destroy his house!!!

I can't see how you can recommend such an option without measuring the
conditions inside and outside his house with data loggers and his wood
moisture in the basement walls using a wood moisture meter.

You have lots of nifty formulas Nick, but seem to have no idea on
proper practical application. Here in the "land of the midnight
fungus", recommending ventillation to solve such a problem is
downright irresponsible!

Please remember Nick, most people with mosture problems do not live in
dry climates! Therefore dehumidifiers are usually a better solution to
high humidity than exhaust fans.

By the way, if he installs a $250.00 dehumidifier instead of a
$1,000.00 Humidex exhaust fan, the money he saves on equipment will be
enough to pay for dehumidifier electricity for many, many years!! And
his walls will be safe!

Please start recommending practical solutions that are climate
specific, instead of your pie in the sky (unless it is cherry pie)
control schemes requiring computers and more psychrometric knowledge
than the homeowner is likely to ever possess.

Stretch

On 19 Jun 2005 08:42:02 -0700, "Stretch" wrote:

Nick, you scare me.

He has basement mildew on his thoughts :-)

I can't see how you can recommend such an option without measuring the
conditions inside and outside his house with data loggers and his wood
moisture in the basement walls using a wood moisture meter.

It's easy in Nick-land - the laws of physics are a bit
different there, and very much more flexible :-)

You have lots of nifty formulas Nick, but seem to have no idea on
proper practical application. Here in the "land of the midnight
fungus", recommending ventillation to solve such a problem is
downright irresponsible!

But .... but .... it looked good in his little Qbasic program
at his desk !!!!!!


Please start recommending practical solutions that are climate
specific, instead of your pie in the sky (unless it is cherry pie)
control schemes requiring computers and more psychrometric knowledge
than the homeowner is likely to ever possess.

Or, indeed, Nick himself :-)


Click every day here to feed an animal that needs you today !!!

http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'

HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
Free Temperature / Pressure charts for 38 Ref's http://pmilligan.net/pmtherm/

wrote in message
...
On 19 Jun 2005 08:42:02 -0700, "Stretch" wrote:

Nick, you scare me.

He has basement mildew on his thoughts :-)

I can't see how you can recommend such an option without measuring the
conditions inside and outside his house with data loggers and his wood
moisture in the basement walls using a wood moisture meter.

It's easy in Nick-land - the laws of physics are a bit
different there, and very much more flexible :-)

You have lots of nifty formulas Nick, but seem to have no idea on
proper practical application. Here in the "land of the midnight
fungus", recommending ventillation to solve such a problem is
downright irresponsible!

But .... but .... it looked good in his little Qbasic program
at his desk !!!!!!


Please start recommending practical solutions that are climate
specific, instead of your pie in the sky (unless it is cherry pie)
control schemes requiring computers and more psychrometric knowledge
than the homeowner is likely to ever possess.

Or, indeed, Nick himself :-)

Paul

This is Turtle.

Never try to put down someone that is way above your level of abilitys for you
will look like a Fool.

TURTLE

Stretch wrote:

Move to South Carolina and try your idea here.

No thanks. Altho houses in western NC seem cheap. BTW, this scheme might work
in a reasonably airtight house that can store some dryth in Charleston, with
w = 0.0166 on an average July day and w 0.0100 from October through April.
I could determine that with a little TMY2 simulation. You probably couldn't.

It does not matter what the RH differaece is unless the temperature is
the same when you ventilate.

I'm not sure what you are saying or why you are saying it, but it seems
to me that you are wrong. For instance, if a basement is 50 F at 70% RH
and outdoor air is 40 F at 50%, it's time to ventilate. Perhaps you would
like to clarify your claim. I also suggested a way to make a bit of indoor
and outdoor the same temp so we could simply compare RHs as a measure of
the humidity ratios. Sounds like you didn't understand that. You may be
over your head and mired in old cut-and-dried HVAC techniques in this case.

If the humidity ratio(in grains of water per pound of dry air) is higher
outside than it is inside, you DO NOT want to ventillate!

That's what I said (with one L :-)

If the humidity ratio is lower outside than inside, then ventilating MAY
do the trick.

It will. The question is how often that happens and for how long, compared
to how fast the house collects moisture and how much it can store. Looks like
it works fine in Phila, with a max 75 wet hours in a row in a typical year.

Either way, you MUST be sure that the surface temperatures in the basement
are ABOVE the dew point of the air present.

Now think hard: if we ventilate when the weight of water in a pound of
basement air is more than the weight of water in a pound of outdoor air,
we are removing water from the basement. If you think we are adding water,
where do you think it comes from?

If the air outside is dryer than the air inside, but the wall temperatures
in the basement is still below the outside air dew point, ventillation
WILL NOT HELP!!!!!!!!!

I disagree (with one L and an "are" vs "is" :-)

Using fans with an improper control system can rot the walls out!!!

I suggest using fans with a proper control system.

In order to determine the proper fix for the OP problem, I would want
to check the weathe data for his area, measure the wall temperatures
over time with data loggers and measure the humidity inside and outside
over time with data loggers.

That might see you into retirement.

Using your RH sensor scheme may destroy his house!!!

Nope. The patent described a technique for drying out flood-damaged houses.

I can't see how you can recommend such an option without measuring the
conditions inside and outside his house with data loggers and his wood
moisture in the basement walls using a wood moisture meter.

I know... Pity.

Here in the "land of the midnight fungus", recommending ventillation
to solve such a problem is downright irresponsible!

Recommending dehumidifiers to solve such a problem is downright irresponsible!

Please remember Nick, most people with mosture problems do not live in
dry climates! Therefore dehumidifiers are usually a better solution to
high humidity than exhaust fans.

I disagree (about moIsture :-)

Please start recommending practical solutions that are climate specific...

Unlike you, I've been doing so all along, with detailed weather data.

Nick

Nick, The weather data is nice, but only available for selected cities.
The weather data says 78 degrees wet bulb here in Myrtle Beach, but I
commonly MEASURE over 80 degrees wet bulb.. Yesterday it was 83 degrees
wet bulb in Murrells Inlet for 3 hours. Murrells Inlet is just 15
miles south of Myrtle Beach, SC.

BTW, I am glad you are a good speller.


If the air outside is dryer than the air inside, but the wall temperatures
in the basement is still below the outside air dew point, ventillation
WILL NOT HELP!!!!!!!!!


I disagree (with one L and an "are" vs "is" :-)

You can disagree all you want, the walls will still sweat!

Stretch

Hi,

Thanks for all the feedback. I don't think I have a problem, but I am
wondering if there is low tech method to check the temp of the inside versus
the outside. I am thinking just a few data points over the week with a
thermometer outside and one inside? Does it need to be on the wall?

I think I am looking for general best-practices if one is in the planning
stages for re-finishing the basement. Unfortunately, the basement only has
one door to outside, but no windows.

As for best practice, using a de-humidifer appears to be a good one for the
list. I have a sump-pump and that could be used to get water out. True? That
is where a/c for house dumps it water.

I had seen in a mag some type of flooring material to put over concrete
floor and then just thought maybe there were other best-practice
construction ideas.

But, it sounds like some solutions might not be good, but depend on the
problem. Not clear I have a problem, though.

Any other comments welcome. Thanks for your time and advice.

Thanks.

JIm

"Stretch" wrote in message
oups.com...
Nick, you scare me.

Move to South Carolina and try your idea here. Then after your house
rots down, you can move back up north.

It does not matter what the RH differaece is unless the temperature is
the same when you ventilate. If the humidity ratio(in grains of water
per pound of dry air) is higher outside than it is inside, you DO NOT
want to ventillate! If the humidity ratio is lower outside than
inside, then ventilating MAY do the trick. Either way, you MUST be
sure that the surface temperatures in the basement are ABOVE the dew
point of the air present. If the air outside is dryer than the air
inside, but the wall temperatures in the basement is still below the
outside air dew point, ventillation WILL NOT HELP!!!!!!!!!

A dehumidifier will use more electricity, but is not likely to damage
anything. Using fans with an improper control system can rot the walls
out!!! The cost of repairing the walls will be MUCH HIGHER than the
cost of the electricity saved!

In order to determine the proper fix for the OP problem, I would want
to check the weathe data for his area, measure the wall temperatures
over time with data loggers and measure the humidity inside and outside
over time with data loggers. He will be safe, if a littel poorer with
a dehumidifier, assuming he drains it outside or into a proper drain.
Using your RH sensor scheme may destroy his house!!!

I can't see how you can recommend such an option without measuring the
conditions inside and outside his house with data loggers and his wood
moisture in the basement walls using a wood moisture meter.

You have lots of nifty formulas Nick, but seem to have no idea on
proper practical application. Here in the "land of the midnight
fungus", recommending ventillation to solve such a problem is
downright irresponsible!

Please remember Nick, most people with mosture problems do not live in
dry climates! Therefore dehumidifiers are usually a better solution to
high humidity than exhaust fans.

By the way, if he installs a $250.00 dehumidifier instead of a
$1,000.00 Humidex exhaust fan, the money he saves on equipment will be
enough to pay for dehumidifier electricity for many, many years!! And
his walls will be safe!

Please start recommending practical solutions that are climate
specific, instead of your pie in the sky (unless it is cherry pie)
control schemes requiring computers and more psychrometric knowledge
than the homeowner is likely to ever possess.

Stretch

Hi again,

Forgot to mention we are on East Coast in Maryland. It does get humid in
summer. Winter not too cold, but humidity is always up there during the peak
of summer.

Thanks.

JIm

"Stretch" wrote in message
oups.com...
Nick, you scare me.

Move to South Carolina and try your idea here. Then after your house
rots down, you can move back up north.

It does not matter what the RH differaece is unless the temperature is
the same when you ventilate. If the humidity ratio(in grains of water
per pound of dry air) is higher outside than it is inside, you DO NOT
want to ventillate! If the humidity ratio is lower outside than
inside, then ventilating MAY do the trick. Either way, you MUST be
sure that the surface temperatures in the basement are ABOVE the dew
point of the air present. If the air outside is dryer than the air
inside, but the wall temperatures in the basement is still below the
outside air dew point, ventillation WILL NOT HELP!!!!!!!!!

A dehumidifier will use more electricity, but is not likely to damage
anything. Using fans with an improper control system can rot the walls
out!!! The cost of repairing the walls will be MUCH HIGHER than the
cost of the electricity saved!

In order to determine the proper fix for the OP problem, I would want
to check the weathe data for his area, measure the wall temperatures
over time with data loggers and measure the humidity inside and outside
over time with data loggers. He will be safe, if a littel poorer with
a dehumidifier, assuming he drains it outside or into a proper drain.
Using your RH sensor scheme may destroy his house!!!

I can't see how you can recommend such an option without measuring the
conditions inside and outside his house with data loggers and his wood
moisture in the basement walls using a wood moisture meter.

You have lots of nifty formulas Nick, but seem to have no idea on
proper practical application. Here in the "land of the midnight
fungus", recommending ventillation to solve such a problem is
downright irresponsible!

Please remember Nick, most people with mosture problems do not live in
dry climates! Therefore dehumidifiers are usually a better solution to
high humidity than exhaust fans.

By the way, if he installs a $250.00 dehumidifier instead of a
$1,000.00 Humidex exhaust fan, the money he saves on equipment will be
enough to pay for dehumidifier electricity for many, many years!! And
his walls will be safe!

Please start recommending practical solutions that are climate
specific, instead of your pie in the sky (unless it is cherry pie)
control schemes requiring computers and more psychrometric knowledge
than the homeowner is likely to ever possess.

Stretch

"Stretch" wrote:

...if he installs a $250.00 dehumidifier instead of a $1,000.00 Humidex
exhaust fan, the money he saves on equipment will be enough to pay for
dehumidifier electricity for many, many years!!

A Smart Vent seems like a much better solution to me.

From:
To: nick pine
Sent: Monday, June 20, 2005 1:29 PM

We recently received data from an outside, independent year-long
investigation of a Smartvent equipped crawl space. Data was collected
every 4 hours.

Crawl space humidity averaged 46% for the year.

If you would like information about our new HI-IQ ventilator that
pressurizes a home or commercial building with fresh, filtered outdoor
air, let us know. This is the preferred approach throughout most of the
US. In fact, the HI-IQ is the only residential ventilation system that
measures outdoor weather. This product also uses our patented vapor
technology, outperforms ERVs HRVs and at 1/3rd the installed cost.

Used throughout the US, from Florida to Alaska, one Smartvent crawl space
ventilator usually will handle about 1800 sqft. In some cases, special
designs with extra fans are employed. In Hawaii, a 6400sqft crawl space
has additional Smartvent fans and an internal fan as well, all controlled
by one Smartvent main unit. Coastal areas usually need double capacity.

Take a look at the attachment enclosed with this email. It may shed some
light on better ventilation. Few understand the capacity of vapor
pressure based ventilation. Other foundation vents are usually closed by
hand (not sealed), and air will leak through the louvers of all your vents
when the Smartvent runs, rather than just the closest vents.

Virtually all passively ventilated crawl spaces throughout the entire US
exceed 90% RH throughout the summer, so mold and moisture damage are
serious issues.

High humidity in crawl spaces assists growth of molds, spores, and
bacteria. Under a vapor barrier, the humidity is 100%. About the only way
to keep these from migrating into the home is to cut the moisture and
ventilate, slightly depressurizing the crawl space.

Since a crawl space is never cleaned there are dead Ocritters¹, critter
droppings, etc. There may be radon or chemicals in the crawl space.
Gases from all these sources will migrate into the home unless exhausted
to the outside, replaced with fresh air.

On our web site, http://www.smartvent.netcrawlspacevent.htm if you look at
the Crawl Space Moisture Control Study, its chart on page 2, you will see
airborne water vapor is a controlling factor in crawl space humidity.
Measuring only humidity is likely to aggravate a moisture problem. The
original Smartvent that generated the information for the Crawl Space
Moisture Study produced about 90-100 cfm. The new model has been measured
at 295CFM, has upgraded software, and is considerably more effective.

To compare the Smartvent with other systems, the Smartvent is the only
system to compare inside and outside water vapor content. Some other
systems have fans on timers, some operate by measuring crawl space
humidity. Both systems are likely to make crawl space humidity worse.

Installation is fast, installing a foundation vent with clear, outdoor, 35
or 50yr caulk; looks good, cleans up easy. We provide a 6' power cord
that you plug into a 120 volt receptacle in your crawl space. That is all
the wiring you need, no remote mounting required.

Dimensions of the Smartvent are 15 1/4 x 7 7/8 x 8, just slightly smaller
than a concrete block. A Smartvent costs only about $8.00 a year to operate.

You can purchase the Smartvent directly. The Smartvent is $365. We ship
upon receipt of a check, or UPS C.O.D at $8 extra. A two year replacement
warranty is in place. For a C.O.D. shipment, email us the address, and
we likely will ship same day. Note that with a C.O.D. someone must be
there to hand UPS a check.

Larger homes can daisy chain a 2nd (or 3rd, etc.) Smartvent fan-only unit
from the first fan/controller unit. The 2nd unit is $195.

Usually we ship same or next day.

Smartvent, Inc.
3255 Cimarron Drive
Conway, AR 72032

phone 501 329 4915
fax 253 295 9111