preparing to blow insulation, caveats tips?

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  #1  
Old 12-11-06, 04:41 PM
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preparing to blow insulation, caveats tips?

I have a 1850sq ft. ranch style 1960s vintage in houston,tx. My insulation vaires from 5 inches to 0 in some places(serioulsy- can see the drywall in places-sad). I was planning on blowing insulation to take it to R30 or R38.

I was going to finish sealing off any pipes/electrical holes in the attic that run into the walls, finish installing soffit vents (with plastic vent protectors-and already have a nice ridge vent) and buy cellulose from H.D. and get the free blower and blow it myself. I have a nice $40 respirator mask.

Few questions:
1)Cellulose is 'best' right? I've seen it recommended b/c it is cheaper and prevents air flow right? Will the weight of the cellulose cause any problems in my attic with causing the drywall to sag?

2)Respirator o.k. It has 2 replaceable cartridges and was the most $$ one I saw at H.D. Wears goggles also I guess?

3)I've found some video on the internet showing how to blow- put pipe parallel to flow, raised a few feet, and blow about 10' away- sond right?

4)What about machine settings? Can the H.D. guys help me, or will it just say on the bag?

5)I have 2 can lights, I just need to keep insulation 3" away from it right? Maybe make some barrier with cardboard or something?

6)I have my air ducts running sometimes suspended from the ceiling. Should I take those down from the ceiling and put them on the rafters so they are covered with insulation or just leave them up there. Maybe add more insulation to them (when the a/c first comes on in hot summer the air is rather hot from them...)??

7)any other tips? Doesn't seem to be too hard right- a relatively handy DIY guy can get it down I assume...

Thanks!
You guys are the best!!
 
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Old 12-11-06, 06:40 PM
airman.1994's Avatar
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Few questions:
1)Cellulose is 'best' right? I've seen it recommended b/c it is cheaper and prevents air flow right? Will the weight of the cellulose cause any problems in my attic with causing the drywall to sag?

Cellulose will not stop air flow. That would be spray foam.
 
  #3  
Old 12-11-06, 07:07 PM
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I guess I didn't mean stop 100% air flow- meant more that it would reduce airflow more than fiberglass insulation thereby reducing attic/wall-house air exchange. Welcome any more comments
 
  #4  
Old 12-13-06, 06:43 AM
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1. Cellulose is a better product when compared to the type of coverage it causes and the R-Value per inch verses the costs of other products out there.

2. Always wear protective clothing when working with any type of insulation, especially when blowing in method is used. Cellulose has the least amount of harmful contaminants among the types of insulation but it does create a good deal of dust while being installed.

3. Generic procedure. Different equipment have different procedures. Read the instructions before using any type of equipment, regardless who tells you how to use it. It will SAVE you TIME.

4. Same as 3.

5. http://www.neo.state.ne.us/home_const/details/rcld.htm

Read this first and NOTE: Canister is "IC" rated.

6. "A chain is only as strong as its weakest link". Heat, Water, Electricity, etc. will always seek the path of least resistance. While all 3 heat transfer mechanisms (Conductive, Convective and Radiant) are always present, Newton's third law of Motion applies. "For every action, there is an equal reaction". The added insulation may address Conductive heat transfer your ceiling but due to the natural buoyancy of warm air, the majority of the heat loss will be through your ducts. The duct insulation at best will have an R-5 value. So even with the added insulation value to the floor of the attic to R-38 but due to the ducts above the insulation, your attic will essentially have an R-5 value. Dropping the ducts and insulating over them increases the effectiveness of the "Thermal Boundary" of the structure as a whole.

TIP: (Staple gun, Tags and String) Staple a line of string to the rafters after dropping the ducts to the floor. Have the string mimic the ductwork on the floor. Tag areas on the string where the main duct is, couplings and dampers are located. Especially Label to which room the duct is going to. Once you bury the ducts under the insulation, you do not want to step on them or anyone else. And you want to be able to find a certain duct if need be.

7. http://www.eere.energy.gov/buildings/info/documents/pdfs/26447.pdf

Read this, it concerns the "Attic Bypass Phenomena" based on the same principles as #6.

Also read up on "Adequate Free Attic Ventilation". I wrote an Article on it several years ago and placed on my website, www.resercon.com
 
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