Hi out there. I have been running into customers that want to upgrade their wall insulation, but have batts in the walls. In checking with local insulation companies, one says he has foam injection system that works but is $2.00 a sq. ft., the other says there is nouthing he knows of that works. Let me know whats going on out there, so I can pass good information on to my customers.

Have a Great Day!!!!!!!

Views: 150

Reply to This

Replies to This Discussion

There are foam companies that will add foam to existing batt insulation, but I'm a skeptic and would want some guarantees and lots of IR pictures.  Maybe even a few addresses where this has been done before so I can look with my own camera.

Improving 3.5 inch walls is difficult.  If the foam can be done and done right, maybe, but at $2 a sq ft a 1,500 sq ft ranch would be around $2,500, I would run some numbers to see if that works.

In the long run, I always look inside and outside to see if other work is in the near future.  If new siding will be needed soon, then adding rigid foam under the siding might combine to be a lot less expensive.  If inside renovations are planned, padding out a wall, electric, windows, yada, yada, may also be an option.

One of the problems with adding foam to an already insulated wall is that the increase is not all that much and the existing fiberglass actually gets in the way reducing the quality of the new install.  So you end up going from an 11 or 13 cavity to a 15 or 18 cavity.  It would be better if the fg wasn't already there.  Those numbers came from my back pocket area so take your own guess, but they illustrate that the improvement isn't all that great.  Adding a couple of inches of rigid over the outside with new siding also covers from foundation to top plate along with all of the thermal bridging.  Much more impressive results.


Thanks, kind of what i was thinking. Lets see what others think.

I'm going to back Bud on this one. Spraying in foam and hoping it will effectively fill in around the FG is essentially hopes and dreams kind of thinking.

In a case such as yours, the best bet is to tighten up where you can, add insulation to places like the rim\band joists (if exposed), and begin to plan for a more comprehensive project in the future (where wall insulation is combined with interior renovation and\or siding replacement). 

In my neck of the woods, most houses are faced with a brick veneer (with no insulation in the walls), so the only real way to approach this is to talk to them about making a mess in their houses and them becoming okay with this over time. By "this" I mean the mess that typically accomodates drilling into the sheetrock\plaster, installing cellulose or icynene, and then patching up the holes used to install the insulation. 




  • Add Videos
  • View All


Latest Activity

Debra Little posted a video

Building Carbon Zero 2015, PHCA

Building Carbon Zero 2015. Passive House CA with City of Palo Alto 2015 summit. Produced by Debra Little. Shot on iPhone 5. Everyone can make videos with the tools in your back pocket!
1 hour ago
Home Energy Magazine's blog post was featured
10 hours ago
Profile IconDave Chamberlain, angela stanzione and Bruce Zahn joined Home Energy Pros
10 hours ago
Paul Holder added a discussion to the group Energy Auditing Equipment for Sale, Trade or to Purchase

Blower Door frame

Looking for a blower door frame for Minneapolis blower door. Needing a 2nd. frame if anyone has one…See More
14 hours ago
Joe Urycki replied to Joe Urycki's discussion TEC blower door and UEI combustion analyzer for sale in the group Energy Auditing Equipment for Sale, Trade or to Purchase
"Yes, I do still have the equipment.  Are you interested in it?"
Amber Vignieri commented on Amber Vignieri's blog post Even with Polar Vortex, Hourly Pricing Participants Saved
"Thanks for your comment Bob! We couldn't be more excited about the increasing prevalence of…"
Home Energy Magazine posted a blog post
Noah Ray Sanders replied to Steve Mann's discussion TEC Blower Door Frame in the group Energy Auditing Equipment for Sale, Trade or to Purchase
"If so please contact me 8329717862 or email noahraysanders@hotmail.com"

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service