# Cellulose vs Fiberglass in Florida, Weight Concerns, Cost



## 6273909 (Nov 15, 2012)

I have a mobile home with 1508 square feet of living space. It currently has maybe an R-5 to an R-10 in the attic now of cellulose. It varies from 7 inches to zero inches, probably from wind while it was being moved. Most of it looks like 2" to me. Supposedly it started off as an R-11 but I think they cheated. I have a 4 ton air conditioner that is loosing ground on days in the 90's. I can set it to 72 but it can go up to 74, throw in a couple of grand kids running in and out and it can get to 80. The air conditioner never shuts off during the day if it is in the 90's. I had the air conditioner checked and it got a clean bill of health, lowering the temperature by 20 degrees; return vs closest vent. I was told by the a/c guy I needed more insulation, not more air conditioner. I called my local insulation company and they priced adding R-19 $525, R-30 $765, R-38 $995. Fiberglass or Cellulose, same price. Their would be an additional charge for adding 58 baffles at $4 each, and I need 58 of them. It doesn't have any baffles now. In the wonderful world of mobile homes you don't always get what you think you are getting. My home has 2"x6" walls, with R-15 insulation in them I hope. You would think thick walls would equal thick trusses but it is just the opposite, the trusses are 2"x2" and 24" on center. I was shocked to see the trusses. I had to cut an attic access so it was my first time seeing the trusses. 
I was considering adding R-38 cellulose insulation but am a little concerned about the weight of 1463 pounds. I could go with R-38 fiberglass which is 850 pounds. The insulation contractor said R-30 was enough and I was probably throwing money away by adding more than the R-19. The insulation contractor suggested I add more roof vents as I only have one, he said add 3-5 more but I would have to get a roofer to do that. 

I would like to ask people who know about insulation what they suggest I should go with?


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## Windows on Wash (Aug 30, 2011)

More is more, however, there is certainly a diminishing law of returns when it comes to insulation thickness and Energy transfer.

R-38 total should be plenty.


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## joecaption (Nov 30, 2011)

No one knows where you are because there's no location in your profile, hard to suggest how much insulation you need without more info.
http://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table
What type roofing? Metal, shingles?
Any soffit vent's?
The weight you quoting is the total amount in one pile, spread out it's going to be way less per sq. ft.
No form of venting is going to work right without soffit venting for make up air.
Nothing would surprize me in most mobile homes.
I used to own a Marlette home.
The dealer when we went to look at them pulled out a ladder and we went up on the roof and he jumped up and down on the roof.
This guy must have weighed 250 lb.
We went down the hall and he banged on the walls.
There was sheetrock behind the paneling.
There was 10" of insulation in the attic, vinyl double hung windows, all Fridare appliances, 3/4 T X G plywood subfloors.
Real door knobs on the closets, not plastic with magnets.


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## 6273909 (Nov 15, 2012)

joecaption the home is located in Bay County Florida, we are 1/4 mile from the ocean and 150 feet from water. Very high humidity, and salt in the air. The soffits are vented all the way down both sides, plenty of airflow available up just very limited on the out. The roof is shingled, 3 tab, and they are white. The home is 26 feet wide plus the overhang and the I think the pitch is 3/12. We have vinyl double pane windows too. The air conditioner duct work is in the attic and it is a split unit with the air handler in a utility closet. 
This is a $98K mobile home, new, and most people don't realize it is a mobile home. I bought it as a repo and got a great deal. The drywall is foamed to the rafters and it will never fall unless the truss comes with it, my fear. The attic is not foamed, they just used foam as a glue.


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## Windows on Wash (Aug 30, 2011)

http://www.greenbuildingadvisor.com...science/diminishing-returns-adding-insulation


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## Gary in WA (Mar 11, 2009)

WoW, I almost hate to post my answer knowing it might be used as your own in the future… . 

827…, IMO, one answer is correct- from your insulation pro; R-19 is enough for your location- hence the energy code requirement. You need to stop the heat from entering the attic, not after it is already there, or the ducts will suffer. 
1. air seal the attic;

2. change to reflective roofing OR a radiant barrier;

3. increase your ventilation (also slows convective looping), as you mentioned;

4. air-seal/insulate (more)/vapor barrier the HVAC ducting;

5. add more blown-in (cellulose at 3” will also stop convective loops) and/or add a housewrap to stop CV’s


Gary


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## 1985gt (Jan 8, 2011)

Gary in WA said:


> WoW, I almost hate to post my answer knowing it might be used as your own in the future… .


What does it matter where or who the answer comes from as long as the information is correct? Did it ever occur to you that WoW has enough knowledge and background to give his own answers? If not the ability to research and find the answers on his own accord? I don't know him personally but I highly doubt that he sits and waits for you to post something so he can copy and paste it for use at a later date.

Whatever the issue you have with him please stop dragging it in to the forums with your snide remarks, it lowers the enjoyment of the forums for everyone involved. That and it's rather annoying.


Now back to topic.

I agree (not stealing) 

Air seal the attic.

Add the required insulation. I also would not be concerned with the weight as joe said it is spread out over a large area. 

I would also be making sure the ducts are insulated properly and sealed. 

And lastly if it is a metal roof I would add a elastomeric coating to it. If it's shingles you are kind of stuck until it's time to reroof.


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## Gary in WA (Mar 11, 2009)

Thanks for the heads-up. If you knew more about it you would have a different opinion- perhaps in 30 years or so, if that is your date of birth. I should not expect this facet of respect from internet forum friends. Point taken, Gary


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## 1985gt (Jan 8, 2011)

It has nothing to do about Internet forum friends. If it matters I was born in 1078. I have grown up in the industry. I swept the shop floors at 10 or so. I speak of real world experience. When I recite or quote a link it's because it's something I know or have seen of first hand knowledge.


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## 6273909 (Nov 15, 2012)

*Before & After*

So I made my decision and it is installed so their is no turning back. 
I decided to go with fiberglass because we are so close to the ocean and after talking with the insulation company they said no local builders use cellulose withing a mile of the beach. I also added a attic ventilation fan. I have about five times the static 'in' ventilation needed. I have tried it with the fan on and the fan off and it is better with the fan on. We added R-38 over the top of the approx R-5 - R-10. We have about 16" total combined now. We/they added 29, 31 pound bags of OC fiberglass. I have added two charts showing before and after the insulation. My thermostat keeps track of the temperatures. That long straight line in the first chart is where the a/c never shut off for hours. The second chart show how the a/c is only running half the time during the same time of day. Both charts are typical. If you are wondering why the first chart drops off, it started raining.


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## Windows on Wash (Aug 30, 2011)

Great follow up.

Glad to see it worked out for you.


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## digitalplumber (Jul 8, 2011)

1985gt said:


> It has nothing to do about Internet forum friends. If it matters I was born in 1078. I have grown up in the industry. I swept the shop floors at 10 or so. I speak of real world experience. When I recite or quote a link it's because it's something I know or have seen of first hand knowledge.



WOW you are over 900 years old! You have certainly seen climate change! :thumbup:


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## Windows on Wash (Aug 30, 2011)

Doing roofing for as long as he has, I bet he feels like 900 years on Monday AM. 

Ha!!


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## 1985gt (Jan 8, 2011)

I felt like I had been inside a cement mixer today. In-fact the way the day is going is sounds like a much better option. 

Another rain day, going to rain tomorrow, a whole schedule completely out of whack by close to 2 months. People calling wondering when we will be there, another call stating they will be signing the proposals and sending them back when can we get started on the replacement.

I'm due for a vacation, 2017 is looking like it will be a good time! I was able to see the wife and kids this weekend, so that was nice...


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## Windows on Wash (Aug 30, 2011)

1985gt said:


> I felt like I had been inside a cement mixer today. In-fact the way the day is going is sounds like a much better option.
> 
> Another rain day, going to rain tomorrow, a whole schedule completely out of whack by close to 2 months. People calling wondering when we will be there, another call stating they will be signing the proposals and sending them back when can we get started on the replacement.
> 
> I'm due for a vacation, 2017 is looking like it will be a good time! I was able to see the wife and kids this weekend, so that was nice...


Keep the faith brother. 

I will pray for some good working weather and stay safe.


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