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gruntman 02-06-2010 02:28 PM

Attic Insulation
 
I have a 50 year old house with old fiberglass insulation. It was put in upside down and looks pulled up in some areas. Half of the attic is covered by boards that have been nailed down to provide storage space. There is insulation under the boards. I have a ridge vent, two vents on the side of the attic (look loke grated vents) but no sofit vents. The top floor get very cold so someone gave me the idea of putting down more insulation right on top of the old insulation rather than removing it. Is this wise or shoud I just start over?

If I should remove the old stuff - what about the insulation under the boards?

Grumpy 02-06-2010 02:40 PM

Why do you think the insulation was installed upside down? Does it have a kraft face or foil face? If the insulation was improperly installed and is radiant barrier, I would not recommend going over it. If it's kraft faced I don't *think* it'd be a problem to go over, but my suggestion is to call the manufacturer of the insulation you choose to use and ask them. However if it was properly installed, then there is no problem installing new insulation over the old. I recommend blown in place fiberglass or cellulose.

As for the area where it was nailed down or compacted for storage, remove the old boards. If you still desire a storage, my recommendation is to build up a platform using 2x10 or 2x12 over the existing ceiling joists. Then fill that cavity with the blown-in, then plywood over the top. This will provide insulation AND a storage place.

As for the ridge vent and those "grated" vents on those side (thoe are called gable vents)... you have a big No No of attic ventilation. However you also said you have no intake, that's a big No No or ridge ventilation. My suggestion is remove the ridge vent and install a solar poweed gable vent on one of the gables. This will turn the entire attic into a low powered wind tunnel. One vent becomes the intake, and the other the exhaust. Assuming your attic is 1500 sq ft or less. If it's larger, one solar fan might not be enough and you may have to opt for a hard wired gable fan on a humidistat and thermostat. The solar powered fans don't have near the power of a hard wire traditional electric fan.

Gary in WA 02-06-2010 06:26 PM

If it is wrong side up, turn it over and add glass batt perpendicular to the joists. Air seal any ceiling penetrations first. If it is shorter than the joists, remove it and start fresh. If you add cellulose on top it will compress the batts (one pound per 8" deep- vs. 1/3# for fiberglass batt).
If you remove the loose boards and install plywood (0.40 perms), you may get mold because it acts as another vapor retarder. If the joists are 24" on center with plaster (8# per sq, ft.), you may compromise the ceiling structure with cellulose to get your required R-49 if your zip is 049: http://www.ornl.gov/sci/roofs+walls/...on/ins_16.html If you add 2x1o's (2.9# per.sq.ft.) or 12's (3.5# per sq.ft.), be sure to place them on blocking over bearing walls below to not load the attic joists. I would add soffit venting: http://books.google.com/books?id=Z8a...20NFVA&f=false

Be safe, Gary

gruntman 02-06-2010 07:57 PM

Yes, there is a paper backing on the insulation and it is facing up. It looks to be a mess - very dirty and dusty - but I will check to see if it is up to the joists - I'll check on that tomorrow but I dont believe it is.

joasis 02-07-2010 05:26 AM

Blow it with cellulose, and disregard the compression of the fiberglass. The more then better. The issue many take about "settling" is not a big deal, since it literally tightens the barrier as it settles. One more myth about insulation.

And keep in mind, you pay only once for insulation, you pay every month for heat and air.

Chemist1961 02-07-2010 07:29 AM

Blown to R50
 
I had about R14 blown 35 year old attic insulation , so I rented a unit and blew my 4-12 pitch 800' attic to R50, sealing wire and pipe runs and electrical first. I had expanded my sofit vents and ran moore vents as well. I finished by carefully leveling to the exterior walls with a long pole and a foam rake like edge on it. I also super sealed my hatch and built the door up to R50

My energy auditor said I did better than most of the pros do:whistling2: Net result, we blew in approx 35 bales, with water breaks and cleanup 5 hours total including pick up and drop off of blower, COST $290, energy rebate $750. Most stores will lend you the blower for 12-24 hours with purchase

NOTE... I did it in the fall when it was cool and comfortable.

I used blown cellulose although now see Corning has PINK bales for a blower they have and a machine with a shutoff switch on their hose , that would be VERY handy in my experience. Dirty work but a great result. Upstairs is much more even temp now, after improving attic ventilation last summer I expect this summer will be less sticky at night as well

and special bonus... the wife is wearing less FLEECE at night:thumbup:. I am all for preserving fleece

As long as you are not up against VERMICULITE, or claustrophobic, I would rate this project as pretty basic for the average DIY TEAM (this is a 2 person job...) with very satisfying results.:thumbsup:

Watch your step in the attic and if it is a low pitch like mine, wear a bump cap and remember to use a NOSH 95 fibreglass rated mask or better . Take a foam snow sled up to lie on across the rafters and a 10" piece of 2" pvc vac tube for leveling or a VERY light weight rake. Preseal gaps , fans and pipes with spray foam

gruntman 02-07-2010 12:56 PM

Picture of the attic insulation
 
5 Attachment(s)
Here is a picture of the attic. I should have started with this. I have a pic of the backing as well. It does not come to the top of the joists. I pulled up a loose board so you can see what is under it. Nice big antennae was thrown in for free.

handy man88 02-11-2010 08:19 AM

Quote:

Originally Posted by Grumpy (Post 395743)
Why do you think the insulation was installed upside down? Does it have a kraft face or foil face? If the insulation was improperly installed and is radiant barrier, I would not recommend going over it. If it's kraft faced I don't *think* it'd be a problem to go over, but my suggestion is to call the manufacturer of the insulation you choose to use and ask them. However if it was properly installed, then there is no problem installing new insulation over the old. I recommend blown in place fiberglass or cellulose.

As for the area where it was nailed down or compacted for storage, remove the old boards. If you still desire a storage, my recommendation is to build up a platform using 2x10 or 2x12 over the existing ceiling joists. Then fill that cavity with the blown-in, then plywood over the top. This will provide insulation AND a storage place.

As for the ridge vent and those "grated" vents on those side (thoe are called gable vents)... you have a big No No of attic ventilation. However you also said you have no intake, that's a big No No or ridge ventilation. My suggestion is remove the ridge vent and install a solar poweed gable vent on one of the gables. This will turn the entire attic into a low powered wind tunnel. One vent becomes the intake, and the other the exhaust. Assuming your attic is 1500 sq ft or less. If it's larger, one solar fan might not be enough and you may have to opt for a hard wired gable fan on a humidistat and thermostat. The solar powered fans don't have near the power of a hard wire traditional electric fan.

What's better, blown fiberglass or blown cellulose for the attic?

Cellulose seems cheaper because less is required to achieve the recommended R value, but some say cellulose is treated and can have odors or corrode pipes. Also, the fiberglass people say cellulose settles easy.

What's the difference between pink and white blown fiberglass?

http://www.tsicompany.com/insulation.html

http://www.applegateinsulation.com/default.aspx

Grumpy 02-11-2010 09:19 AM

I don't do many insulation jobs but I do a handfull a year. I primarily promote the blown in fiberglass, however have no problem using cellulose. As far as price goes on the average house it's so minimal it's not worth discussing. I know Joasis will disagree with me since he and his son primarily promote cellulose, but these are the reasons I prefer fiberglass:

Fiberglass is non-absorbing. In other words it won't sponge moisture. I have been in cellulose insulated attics which seemed to have wet or damp insulation. True, I was there to solve condensation issues which put that excessive humidity into the air, but I've never seen wet fiberglass insulation in my experience unless there was a roof leak.

Fiberglass is non flammable, and while cellulose is flame resistant it still can burn. A better description is that cellulose will burn when there is fire. Take the fire away and it will quickly go out. In other words it is combustable, but will not sustain combustion... and those are for the cellulose insulations that are treated, because without a treatment it is flammable. Most cellulose is fire retardant now adays... who knows maybe some junk coming out of china is not, but I have seen that fiberglass is fire tested using blow torches.

As for cellulose corrosion or odor I haven't seen it. I think you're fine with either one when properly installed. A poor installation can cause alot of harm. Blocking ventilation, covering can lights, etc.. .

As for the differenc ebetween yellow and pink, I know for sure that the pink is a pigment added primarily by owens corning because pink is their trade mark. Are there any other differences? I don't think so, but I do not know for sure.

I have blown in fiberglass in my own attic that I blew in 2 summers ago.

handy man88 02-11-2010 01:16 PM

Thanks for the detailed response.

If cellulose is found to be wet, from a leaky roof or from condensation, does it need to be thrown out/replaced?

Also, since cellulose is an organic material, is it more likely to get mold vice blown fiberglass?

VelvetFoot 02-11-2010 01:19 PM

Having an attic to store stuff is pretty darn convenient. I wish I could store stuff in mine. Maybe you could get sprayed foam involved in some way.

handy man88 02-11-2010 03:48 PM

Quote:

Originally Posted by VelvetFoot (Post 398173)
Having an attic to store stuff is pretty darn convenient. I wish I could store stuff in mine. Maybe you could get sprayed foam involved in some way.

Not many homes these days have attics designed spacious enough to be considered as storage space. It's usually a spaghetti bowl of wood.

gruntman 12-04-2010 09:01 PM

Its been a long time since I first posted this but I never fixed my attic. Its getting cold up here in Boston again so Im ready to do something. I had ice dams last year. Given that I have 2 gable vents and a ridge vent, someone suggested that I install an electric gable vent on one side. Is that a good idea?


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