Adding another type of insulation?

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  #1  
Old 10-25-15, 08:31 AM
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Adding another type of insulation?

Hi all,

Before the winter really starts I want to add more insulation to my attic. I would ideally like to get the same type of insulation as I already have but I'm not sure what type my current insulation is. I have attached a picture of it. I need to find the type so I can get a R value so I can see what I'm missing.

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My dad wants to use batts since he has done it like 15 years ago but I'm worried that even if I can cut the batts to fit accurately it will just compress the current insulation and it will be less effective. If I go the Batt route then I would first move the current loose fill out of the way then use it on top of the newly installed Batts. Seems like alot of work compared to renting the machine and blowing.

FYI, I live in Quebec Canada.

Any advice is appreciated!
 
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  #2  
Old 10-25-15, 09:00 AM
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My guess is, that's blown in fiberglass, but as for r-value just use r-3 per inch and it will cover most products. I'll assume Quebec City which would have a similar insulation recommendation as northern Maine, which I am quite familiar with. The 2009 US energy codes suggests a minimum of r-49 for northern Maine, but that is a minimum. CA has made the selection process a bit more complicated, link below, by including the cost of energy. The zone for Quebec ranges from 33 to 60. So, IMO, 50 t0 60 would be a good target unless you have a required number already in hand.

You are correct that any compression will lower the total r-value. Although some compression is not bad, it is the loss of inches that lowers the total value.

If that insulation is as light and fluffy as I suspect, any disturbance will greatly reduce its effectiveness. If it is a cellulose product it would be much more durable.

Is it light and fluffy or more dense?

In any case, was any air sealing effort undertaken prior to that insulation being installed? Air sealing can be just as important as insulation and should be done before ell is buried, at least the major leaks.

Baffles in each rafter bay to keep the insulation below the roof and keep it from filling up the soffits. Be sure you have good ventilation.

Some air leak areas: Recessed lights, attic access, chimneys, plumbing penetrations, fan exhaust ducts, electrical boxes and penetrations.

Bud
http://joneakes.com/jons-fixit-datab...ULATION-LEVELS
 

Last edited by Bud9051; 10-25-15 at 09:36 AM. Reason: add link
  #3  
Old 10-25-15, 05:33 PM
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Judging by the look, it may be Cetain-Teed insul safe or Johns Manville Attic Pro. All of the fiberglass manufacturers have a version of the Certain-Teed product and are all basically very light density materials. If you are adding more insulation then you need to match density or you will compress the underlying material.

Maneuvering through the material is quite disruptive to its loft.

You may want to ask the builder of record for the house if they have the information you are seeking. You can also ask a local insulation contractor what materials were popular when the house was built.
 
  #4  
Old 10-26-15, 08:06 AM
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Thanks for the info!

As long as I use another blown fiberglass then I should be alright? I suspect different companies have very similar densities.

I currently have about R20 (6.5" *3)

I plan to staple the baffles in place since some have fallen down or moved over time. I'm sure this will disturb/compress some of the current insulation but its my only option. Maybe I can try and brush it out of the way before I put catwalk wood planks in place.

Another reason for the catwalk is that I want to understand what wires and ducts are running throughout the attic. It looks like its sealed from the small amount of insulation I pushed around but everything else is covered with insulation.

I convinced my Dad to help with blown insulation. Hopefully it will be easier then working with the Batts.
 
  #5  
Old 10-26-15, 09:53 AM
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Some baffles have a flap that is positioned down over the end of the insulation to prevent incoming air flow from blowing right through the insulation or simply blowing the insulation away from the eaves.

Recessed lights should be air tight (AT) and insulation contact (IC) rated.

For a cat walk, installing some 2x6" on edge perpendicular to the joists and then installing some plywood on top of them makes for a permanent walkway that reduces future disturbances of the final insulation. Also, hang notes from the ceiling identifying the location of things you bury. Someone in the future will love you.

Bud
 
  #6  
Old 10-27-15, 09:01 PM
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I have installed extra baffles with staples, only about 6 more to go.

I did take some time to seal the holes that I could find for electrical wires, bathroom fan box, cable, network cable and attic air vent with spray foam. However I'm reading that I should seal the top plates of all internal walls. :/ Obviously this will be pretty hard to do with 6.5 inch of insulation already installed. How important is this task? I can see some type of plastic barrier underneath the insulation all around the attic but it does not cover of the interior walls top plate.

I was pricing at home depot and Cellulose seems to be better for price. Its only $10 per bag compared to $40 for the Atticat bag. After using each websites calculator, Owen's Corning (FG, 15 bags) and Thermocell (Cellulose, 37 bags). Cost is pretty different, 597.45 (FG) vs 338.55 (Cellulose). Many of the site/videos I'v seen comparing them are from either one side or another so no fair comparison. Anything I should really know about each one? They seem fairly similar.

Thanks.
 
  #7  
Old 10-28-15, 06:58 AM
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In a perfect world, everything should be sealed. But once there is insulation in place, the time and effort to go back can exceed the value of that time and effort. Since we don't get A?B comparisons from every house I have to go by what I read and even the top pros will lean towards just sealing the major leaks and call it more than good enough. Next new house you do everything from the start .
Note, there are often other places that the above time and effort will be far more rewarding, like the rim joist if it hasn't been detailed. As an energy auditor I use an infrared camera and without exception I always find an OMG air leak problem, even with new homes. They just can't hide from that heat sensitive camera.

The cellulose is heavier than the fiberglass so it will compress what is already there. But, a little compression isn't bad, just reduces your starting r-20 number, so allow a couple more inches of cellulose. I have often heard of using cellulose as a top cover because it reduces the air infiltration into the fiberglass.

Bud
 
  #8  
Old 10-28-15, 12:18 PM
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Thanks for the comments Bud.

When I spoke with the Home Depot guy he said he never heard of sealing the top plate of the interior walls but maybe he was not the most knowledgeable, who knows. I also agree that the benefit is likely minimal and a pain with 6.5 inch currently and adding 12 inch more would make it impossible later on.

I wish I knew someone with a thermal imaging camera since they seem very pricey. Home Depot does not rent them . Still looking for a local place to rent them. I did double check my conduits/cables/wires that enter the house via the rim joist and made sure they were sealed again with great stuff expanding insulation.
 
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