Home Page link

Insulating below a floor

Home| Search | About
Login Password
Register Now! Lost Password?

Home Repair - - If it ain't broken, don't fix it. Otherwise look here. 

Page 3 of 4       < 1 2 3 > last >> Bookmark this page:  YahooMyWeb Yahoo!  Google Google  Windows Live Favorites Windows Live  del.icio.us del.icio.us  digg digg  Add to Netscape Netscape
Subject Author Date
Insulating below a floor Steve Barker LT 11-10-2006
If you were  Registered and logged in, you could reply and use other advanced thread options
Posted by Edwin Pawlowski on November 11, 2006, 9:26 am



>
> Been there done that, pointless waste of time and materials. The floors
> were nearly, if not, as cold after the install. We did a good job &
> hung R-19 between the joists with chicken wire to hold it in place.
> Warm air rises, cold air sinks you aren't really changing anything.


You certainly are changing things. Heat moves three ways, conduction,
convection, radiation. You are addressing only convection. While hot air
is rising, heat can also be conducted to the ground that is a lower
temperature. Heat always moves to where there is less of it. Laws of
physics, not opinion.

Were the floors as cold after you insulated? Any flat smooth surface is
going to feel cool at room temperature. It has to do with skin contact to
the smooth surface. Your body is about 97 degrees. The floor is about 70
degrees. Following the laws of physics, the heat from your body is drawn to
the cooker surface. A flat wood, tile, or concrete floor is going to feel
cooler than a carpeted one because of the greater surface contact as
compared to a bumpy one with air pockets.

Putting insulation under the floor reduces the amount of heat that can pass
as it is drawn to the cooler area.



Posted by Eric in North TX on November 11, 2006, 10:24 am



All I know is that any other improvement to insulation, (better doors,
better windows, walls stuffed, attic R level raised) have shown a
marked and noticeable difference both in utilities and comfort. The
floor joist job was a 1 on a scale of 1-10 with 1 sucking and 10 as
fantastic, if I had it to do over, I'd just have thrown the same amount
of insulation into the attic.


Posted by Malcolm Hoar on November 11, 2006, 12:23 pm


>
>>
>> Been there done that, pointless waste of time and materials. The floors
>> were nearly, if not, as cold after the install. We did a good job &
>> hung R-19 between the joists with chicken wire to hold it in place.
>> Warm air rises, cold air sinks you aren't really changing anything.
>
>
>You certainly are changing things. Heat moves three ways, conduction,
>convection, radiation. You are addressing only convection. While hot air
>is rising, heat can also be conducted to the ground that is a lower
>temperature. Heat always moves to where there is less of it. Laws of
>physics, not opinion.
>
>Were the floors as cold after you insulated? Any flat smooth surface is
>going to feel cool at room temperature. It has to do with skin contact to
>the smooth surface. Your body is about 97 degrees. The floor is about 70
>degrees. Following the laws of physics, the heat from your body is drawn to
>the cooker surface. A flat wood, tile, or concrete floor is going to feel
>cooler than a carpeted one because of the greater surface contact as
>compared to a bumpy one with air pockets.

Bingo! Air pockets.

Still air is an excellent insulator. Most insulation materials
are largely comprised of ummmm, air.

>Putting insulation under the floor reduces the amount of heat that can pass
>as it is drawn to the cooler area.

The OP already has some of that under the floor. His crawl space
is sealed (not vented) and shallow. Additional insulation will
help in theory but the effect will be insignificant in practice,
in my view.

If his crawl space was 3 foot deep and ventilated, that would
be a very different situation.

--
|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
| Malcolm Hoar "The more I practice, the luckier I get". |
| malch@malch.com Gary Player. |
| http://www.malch.com/ Shpx gur PQN. |
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Posted by Steve Barker on November 11, 2006, 8:26 pm


IF my crawl space was 3', I'd be in hog heaven!! LOL! It's amazing the
planning you have to do with plumbing and electrical if you don't want, (or
can't get) ANY of it below the floor.


Steve


PS. THANKS for all the replies. I think I'll plastic the dirt, and perhaps
foam board around the perimeter and be done. I'll post pictures someday.
<G>

s


>>
>>>
>>> Been there done that, pointless waste of time and materials. The floors
>>> were nearly, if not, as cold after the install. We did a good job &
>>> hung R-19 between the joists with chicken wire to hold it in place.
>>> Warm air rises, cold air sinks you aren't really changing anything.
>>
>>
>>You certainly are changing things. Heat moves three ways, conduction,
>>convection, radiation. You are addressing only convection. While hot air
>>is rising, heat can also be conducted to the ground that is a lower
>>temperature. Heat always moves to where there is less of it. Laws of
>>physics, not opinion.
>>
>>Were the floors as cold after you insulated? Any flat smooth surface is
>>going to feel cool at room temperature. It has to do with skin contact to
>>the smooth surface. Your body is about 97 degrees. The floor is about 70
>>degrees. Following the laws of physics, the heat from your body is drawn
>>to
>>the cooker surface. A flat wood, tile, or concrete floor is going to feel
>>cooler than a carpeted one because of the greater surface contact as
>>compared to a bumpy one with air pockets.
>
> Bingo! Air pockets.
>
> Still air is an excellent insulator. Most insulation materials
> are largely comprised of ummmm, air.
>
>>Putting insulation under the floor reduces the amount of heat that can
>>pass
>>as it is drawn to the cooler area.
>
> The OP already has some of that under the floor. His crawl space
> is sealed (not vented) and shallow. Additional insulation will
> help in theory but the effect will be insignificant in practice,
> in my view.
>
> If his crawl space was 3 foot deep and ventilated, that would
> be a very different situation.
>
> --
> |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|
> | Malcolm Hoar "The more I practice, the luckier I get". |
> | malch@malch.com Gary Player. |
> | http://www.malch.com/ Shpx gur PQN. |
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



Posted by on November 11, 2006, 5:53 pm



>... Your body is about 97 degrees. The floor is about 70 degrees.
>Following the laws of physics, the heat from your body is drawn to
>the cooker surface.

Then again, we have shoes, and a small foot surface.

Nick


Page 3 of 4       < 1 2 3 > last >>
Similar ThreadsPosted
Insulating a floor? June 21, 2007, 11:33 am
Insulating under floor October 16, 2008, 12:36 am
Insulating basement floor July 28, 2005, 12:51 am
Insulating floor joists? September 17, 2006, 9:26 am
Insulating concrete basement floor June 26, 2006, 1:35 am
Insulating floor over unfinished basement. December 25, 2006, 6:56 pm
Insulating method? Shed floor. June 13, 2008, 1:35 pm
Insulating garage in CT October 13, 2005, 6:12 am
Insulating around mudsills... November 21, 2005, 3:20 pm
insulating subfloor December 16, 2005, 5:57 am

Contact Us | Privacy Policy

XML SitemapXML Sitemap