My house has an unfinished attic with a partial floor (maybe 1/8 of
the attic currently has a floor). I am quickly running out of storage
space and would like to put down some simple plywood on top of the
floor joists to serve as a floor for storage. There is currently blown
in insulation through out the attic.

Do I need to remove the blown in insulation and replace with rolled
insulation? I have heard that blown in insulation works best when it
is not compacted, and putting the plywood on top would compact it. But
I have also read some posts around the net that suggested that it was
not necessary to remove the blown in insulation.

Any thoughts or ideas?

Thank you!

Mike

On Thu, 1 Jan 2009 11:51:51 -0800 (PST), Mike Daniska
wrote:

My house has an unfinished attic with a partial floor (maybe 1/8 of
the attic currently has a floor). I am quickly running out of storage
space and would like to put down some simple plywood on top of the
floor joists to serve as a floor for storage. There is currently blown
in insulation through out the attic.

Do I need to remove the blown in insulation and replace with rolled
insulation? I have heard that blown in insulation works best when it
is not compacted, and putting the plywood on top would compact it. But
I have also read some posts around the net that suggested that it was
not necessary to remove the blown in insulation.

Any thoughts or ideas?

Thank you!

Mike

If you are compressing it say one inch out of eight, don't
worry. If you are compressing five inches out of ten, then I would
remove most of it that is over the level you will be putting down the
floor.

BTW adding the floor will increase the insulation a little.

Good Luck

On Jan 1, 1:51*pm, Mike Daniska wrote:
My house has an unfinished attic with a partial floor (maybe 1/8 of
the attic currently has a floor). I am quickly running out of storage
space and would like to put down some simple plywood on top of the
floor joists to serve as a floor for storage. There is currently blown
in insulation through out the attic.

Do I need to remove the blown in insulation and replace with rolled
insulation? I have heard that blown in insulation works best when it
is not compacted, and putting the plywood on top would compact it. But
I have also read some posts around the net that suggested that it was
not necessary to remove the blown in insulation.

Any thoughts or ideas?

Thank you!

Mike

Is it unheated and open to air, wher do you live, what Heat Zone. If
inheated and open the floor is insulating your home, in my area zone 5
about 12" is minimum needed, maybe 17" optimal

any insulation you press down to the thickness of the ceiling joists will
assume the r-value of that thickness.

s

"Mike Daniska" wrote in message
...
My house has an unfinished attic with a partial floor (maybe 1/8 of
the attic currently has a floor). I am quickly running out of storage
space and would like to put down some simple plywood on top of the
floor joists to serve as a floor for storage. There is currently blown
in insulation through out the attic.

Do I need to remove the blown in insulation and replace with rolled
insulation? I have heard that blown in insulation works best when it
is not compacted, and putting the plywood on top would compact it. But
I have also read some posts around the net that suggested that it was
not necessary to remove the blown in insulation.

Any thoughts or ideas?

Thank you!

Mike

"Mike Daniska" wrote in message
...
My house has an unfinished attic with a partial floor (maybe 1/8 of
the attic currently has a floor). I am quickly running out of storage
space and would like to put down some simple plywood on top of the
floor joists to serve as a floor for storage. There is currently blown
in insulation through out the attic.

Do I need to remove the blown in insulation and replace with rolled
insulation? I have heard that blown in insulation works best when it
is not compacted, and putting the plywood on top would compact it. But
I have also read some posts around the net that suggested that it was
not necessary to remove the blown in insulation.

Any thoughts or ideas?

Thank you!

Mike

If anything you would be wanting to *add* insulation to the attice which is
the point of the greatest thermal loss. My blown-in was done by the
previous owner and on top of the glass insulation. Over the past 25 years
it has settled and I have rolled out new batts perpendicular to the joists.
Now, if I were in your situation and wanted to create storage for light
loads in my attic I would make 2x4 standoffs to a height just greater than
the insulation that you have or intend to put down in the future. I would
connect them with 2x4s and top with 3/8" CD ply. JAT
Chuck

C & E wrote:

Any thoughts or ideas?


If anything you would be wanting to *add* insulation to the attice
which is the point of the greatest thermal loss. My blown-in was
done by the previous owner and on top of the glass insulation. Over
the past 25 years it has settled and I have rolled out new batts
perpendicular to the joists. Now, if I were in your situation and
wanted to create storage for light loads in my attic I would make 2x4
standoffs to a height just greater than the insulation that you have
or intend to put down in the future. I would connect them with 2x4s
and top with 3/8" CD ply. JAT

Excellent idea.

On Thu, 1 Jan 2009 15:51:32 -0600, "Steve Barker"
wrote:

any insulation you press down to the thickness of the ceiling joists will
assume the r-value of that thickness.

No. Compressed insulation will have a lower R value. It is the
trapped air that insulates.

Jim

On Jan 2, 7:37*am, "HeyBub" wrote:
C & E wrote:

Any thoughts or ideas?

If anything you would be wanting to *add* insulation to the attice
which is the point of the greatest thermal loss. *My blown-in was
done by the previous owner and on top of the glass insulation. *Over
the past 25 years it has settled and I have rolled out new batts
perpendicular to the joists. Now, if I were in your situation and
wanted to create storage for light loads in my attic I would make 2x4
standoffs to a height just greater than the insulation that you have
or intend to put down in the future. *I would connect them with 2x4s
and top with 3/8" CD ply. *JAT

Excellent idea.


Yeah, except for the fact that in many attics, you don't have much
headroom to begin with and taking 4 inches just makes it less usable.

On Jan 2, 7:50*am, wrote:
On Jan 2, 7:37*am, "HeyBub" wrote:

C & E wrote:

Any thoughts or ideas?

If anything you would be wanting to *add* insulation to the attice
which is the point of the greatest thermal loss. *My blown-in was
done by the previous owner and on top of the glass insulation. *Over
the past 25 years it has settled and I have rolled out new batts
perpendicular to the joists. Now, if I were in your situation and
wanted to create storage for light loads in my attic I would make 2x4
standoffs to a height just greater than the insulation that you have
or intend to put down in the future. *I would connect them with 2x4s
and top with 3/8" CD ply. *JAT

Excellent idea.

Yeah, except for the fact that in many attics, you don't have much
headroom to begin with and taking 4 inches just makes it less usable.

Usable, its an unheated attic for storage not sleeping.

C & E wrote:

If anything you would be wanting to *add* insulation to the attice which is
the point of the greatest thermal loss. My blown-in was done by the
previous owner and on top of the glass insulation. Over the past 25 years
it has settled and I have rolled out new batts perpendicular to the joists.
Now, if I were in your situation and wanted to create storage for light
loads in my attic I would make 2x4 standoffs to a height just greater than
the insulation that you have or intend to put down in the future. I would
connect them with 2x4s and top with 3/8" CD ply. JAT
Chuck

Andy adds:

A good idea, and not very expensive or hard to implement..

Remember tho, that NOTHING stops air from moving like a solid
barrier. When you put the plywood floor down, it makes a solid
barrier
on TOP of the insulation, which means that air will no longer waft up
thru the insulation...

So any R factor you lose by comressing the insulation will be offset
by the fact that you are putting a solid barrier on the top side,
which
means there will be practically no air circulation..... In my
opinion,
the decrease in Rfactor, if there actually is a decrease, will be
negligible for only a couple inches of compression. In fact, it
might
even get a little better, but one would have to experiment to know
for
sure....

If air circulation was NEEDED in the insulation to prevent moisture
buildup, that might cause a problem , depending on which side of
the insulation the high moisture side is on. But it probly wouldn't
bother you much in the technique you are suggesting...

Best of luck on your project.

Andy in Eureka, Texas ...... P.E.

Ideally remove all the existing insulation and replace with expanding
closed cell foam insulation R7 per inch.

the existing fiberglass is likely R3 per inch

the expanding foam seals all the little air leaks so its a far better
insulation

On Jan 2, 9:11*am, Andy wrote:
C & E wrote:

If anything you would be wanting to *add* insulation to the attice which is
the point of the greatest thermal loss. *My blown-in was done by the
previous owner and on top of the glass insulation. *Over the past 25 years
it has settled and I have rolled out new batts perpendicular to the joists.
Now, if I were in your situation and wanted to create storage for light
loads in my attic I would make 2x4 standoffs to a height just greater than
the insulation that you have or intend to put down in the future. *I would
connect them with 2x4s and top with 3/8" CD ply. *JAT
Chuck

Andy adds:

* A good idea, and not very expensive or hard to implement..

*Remember tho, that NOTHING stops air from moving like a solid
barrier. *When you put the plywood floor down, it makes a solid
barrier
on TOP of the insulation, which means that air will no longer waft up
thru the insulation...

* So any R factor you lose by comressing the insulation will be offset
by the fact that you are putting a solid barrier on the top side,
which
means there will be practically no air circulation..... *In my
opinion,
the decrease in Rfactor, if there actually is a decrease, will be
negligible for only a couple inches of compression. * In fact, it
might
even get a little better, but one would have to experiment to know
for
sure....

* *If air circulation was NEEDED in the insulation to prevent moisture
buildup, *that might cause a problem , depending on which side of
the insulation the high moisture side is on. *But it probly wouldn't
bother you much in the technique you are suggesting...

* *Best of luck on your project.

* * * * * * * * Andy in Eureka, Texas ...... P.E.

Wow! Thank you for all of the suggestions and help! I am going to have
to bookmark this group :-)

I think I am going to take a look at going the simple route with some
plywood on top of the blown in insulation in a small part of the
attic, just to see how that works out. Also, just FYI (probably should
have mentioned this first), my home is new construction built in 2005.
The entry way to the attic is from my bonus room, and there is a small
portion that does have a floor. This floor seems like it is higher
than the floor joists (like what C&E suggested about putting down
2x4s). I don't need anything fancy, just some floor to store all the
junk accumulating in the rest of the house. Of course, that is
probably a story for another Usenet group :-)

Thank you again!

Mike

On Thu, 1 Jan 2009 11:51:51 -0800 (PST), Mike Daniska
wrote:

My house has an unfinished attic with a partial floor (maybe 1/8 of
the attic currently has a floor). I am quickly running out of storage
space and would like to put down some simple plywood on top of the
floor joists to serve as a floor for storage. There is currently blown
in insulation through out the attic.

Do I need to remove the blown in insulation and replace with rolled
insulation? I have heard that blown in insulation works best when it
is not compacted, and putting the plywood on top would compact it. But
I have also read some posts around the net that suggested that it was
not necessary to remove the blown in insulation.

Any thoughts or ideas?


Get rid of stuff. Nothing likes attic summer heat anyway.

In article ,
Andy wrote:


C & E wrote:

If anything you would be wanting to *add* insulation to the attice which is
the point of the greatest thermal loss. My blown-in was done by the
previous owner and on top of the glass insulation. Over the past 25 years
it has settled and I have rolled out new batts perpendicular to the joists.
Now, if I were in your situation and wanted to create storage for light
loads in my attic I would make 2x4 standoffs to a height just greater than
the insulation that you have or intend to put down in the future. I would
connect them with 2x4s and top with 3/8" CD ply. JAT
Chuck

Andy adds:

A good idea, and not very expensive or hard to implement..

Remember tho, that NOTHING stops air from moving like a solid
barrier. When you put the plywood floor down, it makes a solid
barrier
on TOP of the insulation, which means that air will no longer waft up
thru the insulation...

So any R factor you lose by comressing the insulation will be offset
by the fact that you are putting a solid barrier on the top side,
which
means there will be practically no air circulation..... In my
opinion,
the decrease in Rfactor, if there actually is a decrease, will be
negligible for only a couple inches of compression. In fact, it
might
even get a little better, but one would have to experiment to know
for
sure....

If air circulation was NEEDED in the insulation to prevent moisture
buildup, that might cause a problem , depending on which side of
the insulation the high moisture side is on. But it probly wouldn't
bother you much in the technique you are suggesting...

Best of luck on your project.

Andy in Eureka, Texas ...... P.E.

Then in that case, simply drill some holes here and there?


David