new insulation over old?

Reply

  #1  
Old 11-13-01, 11:06 PM
Guest
Visiting Guest
Posts: n/a
new insulation over old?

Hello all.
I would like to add some insulation in an attic over older insulation. the older stuff is faced(paper) one side and was, in 62' 3", but seems to have flattened out to less than that. I am thinking of simply applying 6" unfaced over this. Any comments , suggestions appreciated.


thanks in advance

wirenuts
 
Sponsored Links
  #2  
Old 11-14-01, 01:59 PM
Insulman
Visiting Guest
Posts: n/a
As long as the paper on the existing insulation is facing down against the drywall, then you can add additional fiberglass batts over the top without a problem... Be sure not to block off the soffits vents If you have any.. this may require installing proper vents.. You might also consider blowing cellulose in your attic.. Home Depot sells the product and will loan you a blower for free... It would be less exspensive than the fiberglass and easier to install on a redo..

Good Luck

Jim
 
  #3  
Old 11-14-01, 02:04 PM
rbisys
Visiting Guest
Posts: n/a
Greetings, Wirenuts

Adding a 6" batt would help some for the winter but be almost useless for summer time. Fiber glass is only about 10% efficient and is about 98% air space. The radiant heat goes thru it pretty quick.

You can get a three layer radiant barrier material that will be great for winter and outstanding for summer. You can DIY it for about $.26/ sf plus shipping. You need a air stapler or heavy duty (commercial)electric.

If you want more radaint barrier info, enter your search engine, "radiant barrier" or "reflective insulation". Most companies advertise the single layer, but, 3 layer is available from some. The radaint barrier will out perform the fiber glass by a good margin.

Thank you for considering my opinion.
 
  #4  
Old 11-14-01, 11:07 PM
Insulman
Visiting Guest
Posts: n/a
Important facts are available about the true benefits of radiant barriers... before you take for fact what rbisys claims about radiant barriers, it would benefit you greatly to do a search on these products..

here are a few sites that have done testing... and some statements from them...

http://www.eren.doe.gov/consumerinfo/refbriefs/bc7.html

How Effective are Radiant Barriers?
During the summer, an attic radiant barrier, combined with existing R-19 attic insulation, will usually result in a total cooling load savings of 2%-15%. Buildings with little to no attic insulation and more than the usual amount of attic ventilation typically provides the most dramatic energy savings from a radiant barrier. The hotter and sunnier the climate is, the more beneficial the radiant barrier installation becomes. The reduced heat gain may also allow you to install a smaller air conditioning system, which results in even more saved energy.

For buildings in heating dominated climates (and with poor insulation on the attic floor) it is generally far more cost effective to install more than the minimum recommendation of ordinary insulation rather than a radiant barrier. This is because attics are often vented to the outdoors and heat entering the attic in the winter (through the inferior floor insulation) simply leaves the building through the attic vents whether or not a radiant barrier is present.

Also, in cold climates air conditioning is usually a much lower priority than heating. Cold-climate homes also tend to have higher attic insulation levels when compared to more Southern climates. As mentioned before, large amounts of common attic insulation negates much of the usefulness of a radiant barrier even under favorable circumstances.

Two field tests, one in Minnesota and one in Canada, both found that a radiant barrier placed over R-19 attic floor insulation (which is less than half the DOE minimum recommendation for those climates,) found that the radiant barrier contributed to less than a 1% reduction in energy consumption for heating and cooling.

also check out what the Department of Energy has to say about radiantbarriers

:http://www.ornl.gov/roofs+walls/insulation/ins_08.html

Here is what California Department and Water and Power has to say about radiant barriers..

Radiant Barriers
When the sun beats down on the roof, the roofing material gets very hot. That heat passes through the attic to the ceiling of the living space. A radiant barrier is a thin sheet of shiny material that blocks this heat before it reaches the ceiling below. These sheets are stapled to the underside of each rafter. The more reflective side should face the roof. Some people have spread the sheets on the attic floor. That doesn't work well, because dust collects on the surface. Even a thin layer of dust prevents the material from reflecting heat as it should. If your ceiling already has 12 inches or more of insulation, radiant barriers won't save as much money.

Typical Cost: $0.35 per square foot. Typical Yearly Savings: $16.

If anyone is interested in more facts about the so called benefits of radiant barriers over conventional methods of insulation I highly reccommend you do your homework prior to taking the local radiant barrier guru's advice..

good luck

Jim
 
  #5  
Old 11-14-01, 11:10 PM
Guest
Visiting Guest
Posts: n/a
Thank you for your input. This is an older New England home, the only concern is heating bills in winter.
thanx again-wirenuts
 
  #6  
Old 01-02-02, 04:22 AM
gubs18
Visiting Guest
Posts: n/a
are you sure it is Home Depot that lends insulation blower?

Hi,
Are you sure it is Home Depot that lends the insulation blower? I've called here in NJ & they never heard of this service (they don't even rent out that equipment). would follow your advise tomorrow if i found a place that would lend/rent the blower.

thank you (always enjoy reading your advise),
Lou

Originally posted by Insulman
As long as the paper on the existing insulation is facing down against the drywall, then you can add additional fiberglass batts over the top without a problem... Be sure not to block off the soffits vents If you have any.. this may require installing proper vents.. You might also consider blowing cellulose in your attic.. Home Depot sells the product and will loan you a blower for free... It would be less exspensive than the fiberglass and easier to install on a redo..

Good Luck

Jim
 
  #7  
Old 01-02-02, 07:22 AM
Insulman
Visiting Guest
Posts: n/a
I Live in S.E. Michigan and all the Home depots in this area have the cellulose and blowers... They sell the Regal Brand of cellulose... maybe do a net search on regal and see if the supply anyone in your area, It would be my guess they supply the blowers for Home Depot to loan out, in order to be able to sell their products...

Good Luck

Jim
 
  #8  
Old 01-02-02, 11:47 AM
gubs18
Visiting Guest
Posts: n/a
great advise; thank you!

great advise; thank you!

Originally posted by Insulman
I Live in S.E. Michigan and all the Home depots in this area have the cellulose and blowers... They sell the Regal Brand of cellulose... maybe do a net search on regal and see if the supply anyone in your area, It would be my guess they supply the blowers for Home Depot to loan out, in order to be able to sell their products...

Good Luck

Jim
 
  #9  
Old 01-05-02, 06:41 AM
rbisys
Visiting Guest
Posts: n/a
Greetings,

Two items.

Regarding cellulose insulation. I purchased a bag of cellulose from one of the big home suppliers and inspected it. Here's what I found.
Shredded paper, shredded plastic, shredded cloth and God only knows what else. Paper for these products come from recycle bins that are available to rodents and their droppings, urine (animal and possibly human), mold/mildew. You don't know what all is in these products.

Regarding Insulmans comments.

Insulaman is a FG salesman. There's no crime in that (dang it) but over the years I've found that it takes a particular type of person to sell these possibly lethal products. They pick and chose very carefully what they tell you and are not the the least bit shy about streching or denying the truth. I have been selling and installing RBs for about 30 years now and if what he claims to be blanket truth was true, the government would not allow this material to be on the the market. Remember NASA and other government agencies use RBs in their functions. Cal. codes, besides others, include RBs in there energy codes. Inslman has refused to respond to the serious heath and mortallity problems, and the pumped up "R" values listed by the manufacturers. Remember these "R" values are not installed values. I have a standing offer to anyone, that I will insulate their next job free(labor and material) if they can produce test reports from a government approved lab (NAVLAP) showing under installed conditions (summer/winter) that FG gets its advertised "R" values. If interested, ask for details. After thirty years I have not had to install one free job. Since Insulman will not respond to my challange to address these issues, maybe he will if one of you ask him. You might also ask him why the FG industry had the US Senate close down the FTC for two days(1981) until they rescinded regulations that would required ALL insulation manufacturers to test their materials in the installed condition.
Better yet, ask the manufacturers about these issues and also ask them why they refuse to include the effects of radiant energy and moisture on their products. Ask OC why they don't publish the late 1960's in house test results of installed winter conditions on their batt insulation.

The problem with these retro tests is that they are installing the RBs in the least favorable position, on the bottom of the rafters. The most effective way is to install them directly over the insulation( two US areas excepted). To get the best, permanent results is to install a two layer, perforated material. If I got the results he's claiming I would not install them. Besides, 99% of my work is new construction, which is a whole different story.

The material he is quoting is bubble foil which I sell for commercial installtions. By the way if you install bubble foil in a steel roof sys(floating galv-alum) you cant't feel any heat on the foil in the summer. At least I can't. I don't recommend bubble foil for retro attic jobs. There are less costly and just as efficient materials available.

Thank you for considering my opinion.
 
  #10  
Old 01-05-02, 08:27 AM
Insulman
Visiting Guest
Posts: n/a
Rbisys,

Why do you bad mouth me? All I do is offer people advice on what I have learned over the years from experience in the insulation business. But the funny part is, Is yes I sell fiberglass,
almost 6 million dollars in 2001. But this post didnt even relate to fiberglass... I suggested someone use another product other than fiberglass.. Why!!!! Cause it makes sense!!!

I will gladly offer advice which I believe will help people do it themselves...effectively and less costly...

Now as to whether or not I should feel guilty about selling fiberglass because it is dangerous , Its because I dont believe it is... You have posted here numerous times about how fiberglass causes cancer... common sense says if you inhale an inordinate amount of any fibers fiberglass, steel etc.. it will be detrimental to your health.. So if you follow saftey ( ie breathing masks ) precautions the product is not considered to be harmful to humans.

Furthermore in October of 2001 the International Agency for Research (IARC), part of The World Health Organization convened a scientific working group of the worlds leading experts on the health and safety of man-made fibers, including glass fibers to re-evaluate these fibers as to their potential carcinogenic hazard.

Following a thourough review of all the medical-scientific data available. Much to your disliking I am sure rbisys, here is the outcome of that scientific panel.. The panel lowered the classification for glass wool fibers from a Group 2b classification ("Possibly Carcenogentic to Humans") to a Group 3 classification (*not classifiable as to carcinogenicity to humans*)

So perhaps you should quit posting outdated facts..

I do honestly believe that you are commited to your product, and I have no problem with that.. But tests have shown in colder climates Radiant Barriers are minimally if at all effective.. As far as you keep stating no one wll take you up on your offer, perhaps because most people dont have the time for your nonsense..

Last thing, being that I sell fiberglass, wholesale, to a large portion of the contracting field in this area, and already have the outlet to distribute any type of insulation product, dont you think that If I or any of the actual experts in this area thought RB's were worth installing we would sell them along side our other products.. The reason we dont sell them is we know they are not effective in colder climates....

By the way, I have never tried to sell one person anything here, only offer free advice, unlike yourself.. So if this makes me a horrible person in your book so be it :-))

Have a nice Day

Jim
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: