Insulating floor space in attic


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Old 11-02-14, 04:30 AM
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Insulating floor space in attic

Hello, I owned a ranch house that will built in 1959, I never really took notice to the lack of insulation in the ceiling until I just finish installing a new ceiling fan in one of the rooms. Upon closer inspection, it appears that there is only 4" of insulation in the ceiling. I was hoping that the plywood floor in the attic would be screwed down and would be pretty simple to remove, but its not, its nailed down, and it is nailed down good(nail every 4 inches).

The attic floor goes to about 6 feet of front and back wall of the house and stops, exposing the floor joist. It appears I have 2x10 or 2x12 floor joist. I do plan on adding two more ceiling fans, one in the living room and one in the master bedroom, so I do plan on removing some small portions of the floor in the attic (Probably cut the sections then pull them out)

So here were my two ideas.

1. Remove the entire, or most of the floor, remove old insulation and put in new r-38 insulation, then put new plywood down.
2. Use a stud finder on the entire floor, find any cross joist in the floor, cut access holes near them, and cut access holes down the entire center of floor. Blow in insulation from both sides where floor is uncovered and then blow in insulation threw the openings I created.

I know plan 2 wouldn't be perfect, I couldn't be 100% sure if the insulation made it to all places, but I am sure it would double if not triple the insulation in the house.

I know ideally it would be best to just remove the entire floor and blow in insulation, but that is going to be some painstaking work removing all that plywood.

Thoughts?
 
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Old 11-02-14, 08:18 AM
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One of the difficulties you face is locating a vapor barrier. Ideally it should be just above the ceiling drywall below, then insulation. With the layer of plywood over the insulation, moisture that diffuses through the drywall (lacking a vapor barrier) will potentially condense on that cold plywood.

Now, a vapor barrier doesn't have to be a sheet of plastic. The new term is "vapor diffusion retarder" and that can be anything from kraft faced insulation to a good layer of paint.

If you end up not removing that plywood, I would consider opening up some strips every 2 or 3 feet to allow the insulation below to breathe.

Bud
 
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Old 11-02-14, 09:39 AM
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Thanks bud for the helpful advice, So If I took out all the plywood (which I am thinking of doing) and removed all the old insulation, I would need to add some sort of moisture vapor over the drywall first? In that case would I then be able to fill the space clear full of insulation them put plywood back over top?

Or even with the vapor barrier I would need to leave room for it to breath? What I would like to do is remove old plywood and insulation, add a vapor barrier, fill the space full with insulation then put plywood back over top, leaving the front and back sides open like they are now, would this be feasible without a moisture issue?
 
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Old 11-05-14, 12:17 PM
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I had an idea to give the new insulation room to breath. I do want to put the plywood floor back down because we use it as storage. What if I added 2x4 running parallel to the floor rafters and put the plywood on top of this. It would create a completely open channel underneath for airflow while still allowing me to fill the rafters clear full of insulation. Thoughts?
 
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Old 11-05-14, 12:37 PM
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The more you insulate the attic from the living quarters and the more you increase the ventilation the worse the attic will become for storage of anything that couldn't be stored outside under a simple cover.

A properly insulated and ventilated attic is a terrible place for household storage. People don't like it but I advise them to get rid of junk rather than store it in an attic.
 
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Old 11-05-14, 01:01 PM
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LOL Furd " People don't like it but I advise them to get rid of junk rather than store it in an attic." I think that is something we learn with age.

Andrew, sorry for not replying sooner, we have been buried in an early snow and many are still without power. Your second approach seems better to me, as a vapor barrier applied from above, even with the insulation removed, will never be perfect. Moisture finds its way right through those rafters. In some cases, using boards instead of plywood allows the small gaps to provide the ventilation. But you already have the plywood and elevating in is best.

Bud
 
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Old 11-06-14, 07:43 AM
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Lol furd, the only items I really keep in my attic are some storage containers and boxes, nothing of real value. All the valuable items and clothes get stored in the closest in our finished basement. I have lived there all but 4 years and only accumulated a couple items in the attic, so I don't plan on there being all that much junk up there.

Thanks bud for the reply, I am thinking of only putting plywood back down a couple feet around where the staircase is, just to put some stuff at the top if needed. I know its going to be real fun tearing all this plywood up, but it needs to be done because I am also going to be installing ceiling fans in the master bedroom and living room where there is no existing fixtures. A lot easier to run the wiring from above than from below.
 
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Old 11-06-14, 11:13 AM
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If you are careful with sparks, I have used a grinder to take the tops off of the nails and then pulled the plywood up. Then cut the nail flush. Slow, but it keeps from tearing up the plywood. A cats paw can really dig into the plywood. Another option is to flip the plywood before you re-install it.

Another approach, if using a cats paw, is to use a utility knife to remove some of the wood on each side. This allows the cats paw to grab the nail head before it grabs a chunk of wood.

FYI
Bud
 
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Old 11-06-14, 11:15 AM
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My parents were hoarders, cleaning out that old place after their deaths was a major chore. My mother-in-law was a hoarder, her husband used to say she was like a gas in that she would fill whatever container she had. My (former) wife was/is a hoarder, she had every single piece of clothing from her junior high school days as well as every school report she had written from elementary school through college.
I have a tendency toward hoarding but I have successfully fought having a paid storage locker, attic storage space and a yard shed for more than fifteen years. Unfortunately, that does not apply to my garage, yet.

It is because I know first hand what people have a tendency to save that I wrote that post. If all you have is a couple of empty boxes in your attic then more power to you.
 
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Old 11-06-14, 02:03 PM
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I hate clutter, I try to get rid of things that I don't use anymore, one thing I really need to go through is my clothes, so many of them and I don't even wear half of them. I don't ever want to get to the point that I have so much stuff I don't know how to even start cleaning it up.

Bud that sounds like some great advice, whats going to be a real pain is they put a nail every 4 inches, I feel like they were building this house to withstand a tornado, I cut some drywall the other day to install a ceiling fan and its 1" thick!
 
 

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