Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Insulation

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 02-22-2012, 09:30 PM   #46
Member
 
concretemasonry's Avatar
 
Join Date: Oct 2006
Location: Minneapolis/St. Paul, Minnesota - Latitude 45.057 Longitude -93.074
Posts: 3,697
Share |
Default

Spray Foam vs. Fiberglass, anyone done the math?


You cannot get an "exact" analysis of insulation based on the so-called "R-values" that are just short term lab tests (usually an hour or so) to measure the resistance to heat flow of the material itself and that does not accurately the insulation value of a wall. Just used very well by a cute pink feline with Henry Mancini music in the background.

The "R-value" of a material filling a void is very close to being a factitious number for advertising and not real life. Even ASHRE recognizes this effect.

The other factor is the ability of some insulation materials that supposedly do not absorb moisture but hold the moisture and feed mold growth on wood framing. I saw hundreds of those situations after Katrina when homes had to be re-done several times within months.

The newer chemicals in some loose fill can eliminate the mold, moisture and fire problems.

Dick

concretemasonry is online now   Reply With Quote
Old 11-14-2012, 07:09 PM   #47
Newbie
 
Join Date: Nov 2012
Posts: 1
Default

Spray Foam vs. Fiberglass, anyone done the math?


I have fiberglass insulation in my 3500 square foot, all electric, home. My electric bill is less than my neighbors smaller home that has foam insulation. I have r-21 in the 2x6 walls and two layers of r30 in the attic. I spent 4k on insulation an my neighbor spent 16k. My last electric bill was $88.00. We have four people and two electric hot water heaters. My high winter bill was $220 and my high summer bill was $155. We are in South Alabama.

I have double insulated low-e non-filled windows, 34 of them, and 9 exterior doors.

Last edited by 6273909; 11-14-2012 at 07:20 PM.
6273909 is offline   Reply With Quote
Old 11-14-2012, 07:47 PM   #48
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: VA, MD, DC
Posts: 5,544
Default

Spray Foam vs. Fiberglass, anyone done the math?


Poorly installed foam is going to get outperformed by properly installed fiberglass (assuming there is an attention to the envelope).

Spray foam's primary benefit is the combination of air sealant and insulation.

If you are using it just as an insulation, it is expensive and probably wasteful.
Windows on Wash is online now   Reply With Quote
Old 11-21-2012, 09:04 PM   #49
Member
 
cocobolo's Avatar
 
Join Date: Dec 2008
Location: Gulf Islands, B.C., Canada
Posts: 6,505
Default

Spray Foam vs. Fiberglass, anyone done the math?


OK, read the entire thread, and while I don't have much to add a lot of what has been said in here isn't terribly accurate.

One thing I can tell you from experience is this. Many years ago our trusty Canadian Government partially sponsored the installation of UFFI (Urea Formaldehyde Foam Insulation). It was intended to go in to older homes which had either no insulation at all, or possibly the aluminum foil that used to be popular back in the day.

When installed correctly, it only did a so-so job - and I will say why in a second. When installed poorly it was totally useless.

Not only that, but it became dangerous in the event that any moisture got into a UFFI'd cavity.

Subsequent to getting many complaints about UFFI, our trusty Canadian Government (federal) did an about face and then had to sponsor part of the cost for removal of this self same product. I was one of a relatively small handful of people who got a license to remove UFFI. Let me tell you, it was NOT a fun job.

A homeowner could take the UFFI course and be granted a license to remove the UFFI from his own home and thus take advantage of the $5,000 grant for removal. But he could do no others. The course was intended for trades people, typically carpenters.

What I found was borderline disgraceful. It was always easy to tell when the installer knew what he was doing, because the cavities would be correctly filled. When they had no clue, well, some of the messes we uncovered were downright criminal. It was one of those times in our past construction history that every crook wanted to get in on the act and make a quick buck. OK, maybe that's stretching it a bit, but there were more lousy installs than good ones.

Here's what happens with the UFFI installs, and remember this is from personal experience.

I do not ever remember opening any cavity and seeing the whole thing 100% filled. The foam would invariably pull away from one or both sides of the studs, or it would be cracked into large pieces. Please be sure to understand that this had nothing at all to do with any stud shrinkage, as these houses were likely 30-40-50 years old before the UFFI install. The cavities would have been as dry as a bone. A very old bone at that!

So, from observation, I can say that this particular foam definitely shrank once it dried out.

It also caused some serious health problems if a cavity ever got damp or wet. I did find one such case in Trail, where the husband's bedroom was right next to a UFFI'd wall and the stucco outside had a massive crack down the entire wall. He got sick shortly after the install, and neither he nor his nurse wife could figure out what was wrong. His first night in that same room after we pulled the foam out eliminated the trouble, just like that. That was the only case of illness that I encountered, but many others were reported to CMHC as the removals took place.

Whether or not the current batch of foams act any better, I really do not know. But there has been a lot of chat in this thread about lumber shrinkage. If you use KD lumber, surely that shrinkage must be very small. Why could a foam not adhere to the studs in such a case? Is there no flexibility in the newer foams?

I'm in the process of designing a net zero energy home and I came here looking for help with insulation, particularly cellulose. I will post a new question about that.
__________________
Just an old guy messin' with bits of wood...
...the friendliest thread on the site! Come on by.
http://www.diychatroom.com/f49/gulf-...uilding-34958/
cocobolo is offline   Reply With Quote
Old 11-21-2012, 10:15 PM   #50
Member
 
Join Date: Dec 2008
Location: Fairbanks, AK
Posts: 1,845
Default

Spray Foam vs. Fiberglass, anyone done the math?


..."I came here looking for help with insulation, particularly cellulose." That's The Stuff!
jklingel is offline   Reply With Quote
Old 12-09-2012, 12:39 PM   #51
Newbie
 
Join Date: May 2009
Location: New England
Posts: 23
Default

Spray Foam vs. Fiberglass, anyone done the math?


Quote:
Originally Posted by NEFoamer View Post
Here is one case study, I'm sure you can find some more out there, hopefully more specific to your location.

http://advancedinsulationla.com/casestudy.pdf
I have worked on more than a few houses for Habitat and I don't think comparing a house professionally done by a foam company to one done most likely by volunteers makes a valid case study.
parts is offline   Reply With Quote
Old 12-10-2012, 07:50 AM   #52
Exterior Construction
 
Windows on Wash's Avatar
 
Join Date: Aug 2011
Location: VA, MD, DC
Posts: 5,544
Default

Spray Foam vs. Fiberglass, anyone done the math?


Quote:
Originally Posted by parts View Post
I have worked on more than a few houses for Habitat and I don't think comparing a house professionally done by a foam company to one done most likely by volunteers makes a valid case study.
+1

Insulation is probably one of the most improperly deployed items in home construction so I would tend to agree with you wholeheartedly.

Windows on Wash is online now   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
DIY spray foam ACR_SCOUT Insulation 12 12-30-2011 06:57 AM
Caulking and sealing with spray foam Willo Painting 1 12-08-2011 11:03 PM
Home Energy Audit & Spray Foam Insulation sweets Insulation 7 09-08-2011 10:45 PM
stone coated steel and spray foam insulation waternut Roofing/Siding 2 01-15-2011 06:36 PM
question about spray foam Tonglebeak Green Home Improvement 11 02-04-2010 05:38 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.