# Space between floors



## Ron6519 (Mar 28, 2007)

Gaps ,especially vertical openings between floors should be sealed. In case of fire,these gaps will be used as a way for the fire to spread through out the house.
Ron


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## Wildie (Jul 23, 2008)

deerhunter said:


> My house is two stories. I just noticed that there is insulation at the ceiling of the first floor. But there is a gap between that insulation and the up stairs floor. I researched a little bit it seems that it's considered unnecessary to add insulation between floors, because it's like insulating interior walls. But the issue is that the space between first and second floor isn't really air tight, there is one part that's not sealed and opens to the attic (the second floor is in the attic). And even though I can seal this part, there is also the path for the ducts for the first floor AC and heating, which can be hard to seal. What's the common practice in this situation?


 Insulation between floors is usually installed to reduce the transmission of sound. Interior walls are sometimes insulated for this reason, also.
When I built my house, I framed the bathroom walls with off-set studs and wove batt insulation in and out to reduce bathroom noise. 
It seemed to have been effective!


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## Scuba_Dave (Jan 16, 2009)

My house has R25 in the 1st floor ceiling
Keeps the 1st floor warm, & allows enough heat to the 2nd floor
Since its one zone & the 2nd floor is bedrooms its a nice way to save on heating cost
I did seal the gaps in the wet wall between basement & 1st floor, 1st floor & 2nd floor


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## deerhunter (Jan 31, 2010)

I think I should at least seal that space between floor and ceiling. I plan to seal the flex duct path with sheet metal with holes cut out so that the duct can go through. Then tape the edge with foil tape. It's just that spot is pretty hart to reach.


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## Chris893 (Nov 27, 2013)

Ron6519 said:


> Gaps ,especially vertical openings between floors should be sealed. In case of fire,these gaps will be used as a way for the fire to spread through out the house.
> Ron



The reason older homes have gaps between floors is to allow for heat expansion in the winter months up here in the north country where we get a lot of snow. I have a very old house that creaks and snaps when our upstairs loft gets warmed up good.


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## Chris893 (Nov 27, 2013)

The reason older homes have gaps between floors is to allow for heat expansion in the winter months up here in the north country where we get a lot of snow. I have a very old house that creaks and snaps when our upstairs loft gets warmed up good.


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## Chris893 (Nov 27, 2013)

for newer homes, because they are more up to safety standards than older homes


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## Chris893 (Nov 27, 2013)

Sorry for the mess on this page, I'm a new user but what I really am trying to explain is, 
The reason older homes have gaps between floors is to allow for heat expansion of the wood, in the winter months because outside is cold and inside is warm. I have a very old house that creaks and snaps when our upstairs loft gets warmed up good because the wood is expanding, and you can feel the upstairs floor shift about 3 inches to the right and then a few minutes later things start cooling down because there is enough space between the floors for ventilation so the wood can stop expanding and cool down. The floor then slowly creeps back to where it started because the one side of the floor is cooling the wood down so it don't pop and crack the wood.


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## ddawg16 (Aug 15, 2011)

I'm just about finished with a 2-story addition to my house.

When I first saw the requirement to insulate the floor between the 1st and 2nd floor...I questioned the architect....

But now I totally understand. It didn't do that much for noise....but....it made a big difference in temp. The downstairs family room stays a lot warmer....and, the upstairs bedroom does not get cooked.

My inlaws house.....the heat rises...upstairs is too hot...downstairs too cold.


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## Dave88LX (Nov 10, 2011)

Chris893 said:


> Sorry for the mess on this page, I'm a new user but what I really am trying to explain is,
> The reason older homes have gaps between floors is to allow for heat expansion of the wood, in the winter months because outside is cold and inside is warm. I have a very old house that creaks and snaps when our upstairs loft gets warmed up good because the wood is expanding, and you can feel the upstairs floor shift about 3 inches to the right and then a few minutes later things start cooling down because there is enough space between the floors for ventilation so the wood can stop expanding and cool down. The floor then slowly creeps back to where it started because the one side of the floor is cooling the wood down so it don't pop and crack the wood.


Shifts 3 inches? WTF?

I was going to ask about the "heat rises" thing, if it would help to keep the basement temperature conditioned.


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## md2lgyk (Jan 6, 2009)

deerhunter said:


> I think I should at least seal that space between floor and ceiling. I plan to seal the flex duct path with sheet metal with holes cut out so that the duct can go through. Then tape the edge with foil tape. It's just that spot is pretty hart to reach.


Way too much work. Use firestop foam instead. Any big box store carries it.


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## oh'mike (Sep 18, 2009)

2010 post---Interesting none the less-------


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## Gary in WA (Mar 11, 2009)

Always fun to read some of the older posts......

http://www.buildingscience.com/documents/insights/bsi-064-bobby-darin-thermal-performance

"My house has R25 in the 1st floor ceiling
Keeps the 1st floor warm, & allows enough heat to the 2nd floor'--------------- http://www.google.com/url?sa=t&rct=j&q=economic%20thickness%20of%20thermal%20insulation&source=web&cd=1&sqi=2&ved=0CE0QFjAA&url=http%3A%2F%2Fwww.insulright.com%2FPDF%2520FORMS%2Feconomical%2520thickness.PDF&ei=FtlVUYTeDMHwigK4w4CgDQ&usg=AFQjCNGQ62K909YH5ZlVjgAkW8XzKgQkGg&bvm=bv.44442042,d.cGE&cad=rja

"Heat rises"----------- http://learn-science.20m.com/tmyths.htm#myth2

Gary


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