Notices

Foam insulation for walls

Old 12-21-2010, 07:40 AM
  #1  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Sep 2007
Posts: 974
Default Foam insulation for walls

I have an older house with zero insulation in the wall cavities. It has a particle board type sheathing on the wall cavities and then a 4-6" stone veneer. I'm looking at having a company blow foam into the wall cavities. They say they can do this from the outside by drilling a small hole in the mortar for every joist cavity and then filling using a not expanding foam. I'm not sure if this is the best way to go or how I make sure they do the entire wall. They are talking about using a tripolymer foam and it's not cheap.
Battlewagon is offline  
Old 12-21-2010, 08:10 AM
  #2  
Senior MemberCaptains Club Member
 
Join Date: Aug 2002
Location: MA and ME
Posts: 16,795
Default

Spray foam is great insulation if you can afford it. I was unaware it can be done after the fact. I've only seen it done from the inside spraying against the sheathing.

Dense pack is a very good choice for old construction. It's much better than FG.

When SF is applied to the underside of the roof, many times it will void the warranty on the shingles. Shingle warranties suck out of the gate. No need to supply them with ammunition.
Mist-Rest is offline  
Old 12-21-2010, 08:22 AM
  #3  
Senior Member
 
Join Date: Mar 2009
Location: Cape Coral... and NOLA!
Posts: 1,421
Default

There is no way you can tell if it is done properly. Most likely it is not done properly. There are too many cavities that can be missed, and possible fire breaks in the walls blocking the fill.

Also, just a slight overfill....2 seconds. Could mean the difference in a full fill, or a blown out wall. Foam is very powerful stuff.

Shingles...... the major companies now agree foam does no harm to the roof and doesnot void the warranty. Last time I had a warranty problem with a shingle manufacturer was probably 7-8 years ago.

No biggie.

You can PM me if you have any questions.
thermasystems is offline  
Old 12-21-2010, 09:34 AM
  #4  
Senior MemberCaptains Club Member
 
Garett's Avatar
 
Join Date: Feb 2003
Posts: 24,318
Default

Originally Posted by thermasystems View Post
There is no way you can tell if it is done properly. Most likely it is not done properly. There are too many cavities that can be missed, and possible fire breaks in the walls blocking the fill.

Also, just a slight overfill....2 seconds. Could mean the difference in a full fill, or a blown out wall. Foam is very powerful stuff.
Exactly my thoughts.

Because foam expands there is no way the installer can put in the true beneficial amount! The volume blown in would always have to be on the light side....otherwise the installer runs the likely risk of bowing out the drywall inside the house.

And secondly, me personally, I'm not to big on the idea of having holes drill in the stone fascia.
Garett is offline  
Old 12-21-2010, 09:36 AM
  #5  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Sep 2007
Posts: 974
Default

Thanks for the input. Just not sure if I should spend $7500 for 2000 sq ft of wall. They talk about 25% to 50% savings in energy costs - but this insulation is for the walls only. I'm figuring a 10-12 year payback is more realistic. However the rooms should be more comfortable. They seem to be the only company in Baltimore doing non-expanding foam into wall cavities. Looks like the only way to check it is to use a thermal imaging gun but they are very expensive ($5000)
Battlewagon is offline  
Old 12-21-2010, 09:41 AM
  #6  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Sep 2007
Posts: 974
Default

Originally Posted by Garett View Post
Exactly my thoughts.

Because foam expands there is no way the installer can put in the true beneficial amount! The volume blown in would always have to be on the light side....otherwise the installer runs the likely risk of bowing out the drywall inside the house.

And secondly, me personally, I'm not to big on the idea of having holes drill in the stone fascia.
This is the stuff they are using http://www.tripolymer.com/tripolymer/index.html Supposedly no expansion.

But my biggest issue is the drilling into the stone. After looking at it they may be able to do most of the work through the fascia board at the top of the wall. Just drill the stone under the windows
Battlewagon is offline  
Old 12-21-2010, 10:20 AM
  #7  
Senior Member
 
Join Date: Mar 2009
Location: Cape Coral... and NOLA!
Posts: 1,421
Default

If it has no expansion, then it would be the same volume as when it comes out of the tube. Low expansion, yes, none..... no way.

I wouldn't do it, or for that matter try to sell you on it. Do your attic. With the stone veneer you aren't going to see that much benefit over what you have. What you will get is a partially filled wall cavity. They CANNOT control or guarantee what is inside of the wall.... do you have fiberglass? Blown cellulose? BIB system??.. Any of these would be filling most of the cavity anyway and you would be trying to compact the existing system with a "non expanding foam"..... don't waste your money.

Once again, do your attic. If you don't mind the extra footage spray the underside of your roof. It is the best. Worst case spray the floor. Better bang for the buck, if you spray the roof, your attic becomes usable if need be.

Also, if your house is elevated, spray the floor.

Andy
thermasystems is offline  
Old 12-21-2010, 10:44 AM
  #8  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Sep 2007
Posts: 974
Default

The walls are completely empty. Nothing to compact or anything else. The wall is 3/4 plaster/rock board - 3 1/2 air gap - 3/4 wood sheathing - air gap - 4-6" stone veneer. Maybe r-5? Maybe I'll just seal around the outlets and floor penetrations with expanding foam.

Already did blown-in insulation in the attic to over the top of the 2 x 10's Could add more.

How does the foam on the underside of the roof affect the shingles and ice dams etc? What happens when you get a leak? Do you then seal all the attic vents? How thick does it need to be? Cost PSF? I've got a rancher....
Battlewagon is offline  
Old 12-21-2010, 10:56 AM
  #9  
Admirals Club Admiral's Club Member
 
Join Date: May 2008
Location: Philadelphia
Posts: 5,166
Default

I've always understood with insulation if you only get 80% the benefit will be no where near what you would get with 100% properly done.

While I know this is a crazzzzy idea and would be a huge PITA, for 7500 I bet you could have most of the sheetrock in the interior exterior facing walls ripped out and insulated the right way. (you just posted before I finished, Simple sheetrock removal is out so scratch this idea!)

I would also ask about having them cut access holes in between the studs inside and just patch the walls after they are done. Much eaier and ensure's a more consistent job. I would be concerned about having a blow out/structural issues just pumping foam blind into a small space like others have stated.
bjm9818 is offline  
Old 12-21-2010, 11:01 AM
  #10  
Senior Member
 
Join Date: Mar 2009
Location: Cape Coral... and NOLA!
Posts: 1,421
Default

What I was inferring with the wall statement is that the stone is already doing it's job. No, yes, you should seal around as many penetrations as you can.

How big is your house? Power bill? Have you asked some other people in the area with foam insulation what their bills are?

Since you already didi the attic. Just put some more over it. If elevated, do the floor.

I would not do the walls for $7500.

How big is the home?
thermasystems is offline  
Old 12-21-2010, 02:19 PM
  #11  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Sep 2007
Posts: 974
Default

Originally Posted by thermasystems View Post
What I was inferring with the wall statement is that the stone is already doing it's job. No, yes, you should seal around as many penetrations as you can.

How big is your house? Power bill? Have you asked some other people in the area with foam insulation what their bills are?

Since you already didi the attic. Just put some more over it. If elevated, do the floor.

I would not do the walls for $7500.

How big is the home?
Home is 3000 sq ft first floor + 1/2 finished basement. Utility bills about $3400 electric, $3400 oil. I do have 3 teenagers who think light switches only turn lights on and that showers should last 15-20 minutes. Summer / winter hookup on the oil burner.
Battlewagon is offline  
Old 12-21-2010, 02:49 PM
  #12  
Admirals Club Admiral's Club Member
 
Join Date: Dec 2005
Location: north shore of ma.
Posts: 2,396
Default

Originally Posted by Battlewagon View Post
Home is 3000 sq ft first floor + 1/2 finished basement. Utility bills about $3400 electric, $3400 oil. I do have 3 teenagers who think light switches only turn lights on and that showers should last 15-20 minutes. Summer / winter hookup on the oil burner.
HOLY CRAP!!!what are you running/heating???
coddock is offline  
Old 12-21-2010, 03:12 PM
  #13  
Senior MemberCaptains Club Member
 
Join Date: May 2005
Location: Naples, Fl
Posts: 237
Default

There are foams for different applications; for example open cell and closed cell along with various expansion rates.

With such limited information it is tough to make a quality assessment.

A heat load calculation at the minimum or even better a home energy audit will tell you where the greatest energy savings would be relative to money spent.

You might try a BPI certified company or an independent home energy rater. Be leary of free or low cost energy audit offers.

More and more building science professionals and progressive HVAC contractors are using infrared cameras. An infrared camera will show how good a job the insulators did on the wall cavities.

Most likely there are better ways to spend the money that will result in greater occupant comfort and energy savings.

Simply though, the juice may not be worth the squeeze.
Jibara is offline  
Old 12-21-2010, 04:37 PM
  #14  
Senior Member
 
Join Date: Oct 2009
Location: South Coast, MA
Posts: 6,938
Default

I build in the Northeast and do a closed cell foam backed up by unfaced fiberglass batts on all of my new construction. With 2" sprayed in and an R-15 HD batt I get an R-28 with zero air infiltration. My other option is to spray 1" closed cell foam and back it with an R-19 unfaced batt, still no air infiltration but only achieve a R-25, but at a greatly reduced cost. The air infiltration is the key factor in determining the actual R factor, any air leaks greatly reduce the the batts ability to maintain the R value. I agree with most above and would never attempt to spay foam insulate from the outside. What part of the country are you in??? Your utility bills are astronomical, I might start with an updated heating system if I were you.
Reely Nice GW is offline  
Old 12-21-2010, 05:36 PM
  #15  
Senior Member
 
Join Date: Jun 2009
Location: Ojai, Ca
Posts: 3,515
Default

You can have loose insulation blown in from the inside, easier to patch the dry wall. I had our 2000 sq ft house done for $1,100.00. It helped a lot, I recently did some remodeling on the inside that required removal of some dry wall, the stud bays were packed full of insulation.
805gregg is offline  
Old 12-21-2010, 06:13 PM
  #16  
Senior Member
 
Join Date: Mar 2009
Location: Pine Ridge SC
Posts: 550
Default

I agree with the advise you're getting.
Absolutely do not attempt, or let anybody talk you into spraying foam insulation from the outside of your house.
The only way to do it correctly as a retrofit, is to remove the drywall from the interior and spray the foam.
You'll be much happier with the results even with having to replace the drywall.

There are many companies that offer DIY foam kits that will allow you to take your time and do one room at a time.
Using a slow rise formula and flexible inspection camera you'll be able to fill wall cavities in areas like kitchen walls with counters and cabinets.
A good closed cell foam will tie house framing together, stop air infiltration, and make a much quieter efficient home.
leary is offline  
Old 12-21-2010, 07:38 PM
  #17  
Senior MemberCaptains Club Member
 
Join Date: Sep 2001
Location: Chatham Mass
Posts: 588
Default

You say its an old house. How old is it. Any knob and tube? You really dont want to disturb that. All wiring should be done first. Real PIA to rewire after. Just had 2800 sf of walls on 2 floors blown in celllulose for 2 grand interior drill and blow. No fireblocking and wire/stucco outside.. 2 3/8 inch holes in every bay. House was being mudded anyways to smooth out a bad 70s texture so not much extra labor to fix. I would only spray foam on open walls. Most heat loss is vertical or through bad windows and doors anyways. 3 1/2 inch will only get you to about a r 13 anyways. Any chance you can go down from the attic to not fix holes. Get a few estimates. Guys are slow so they may really sharpen their pencil just to keep the guys working.
GOODNYOU is offline  
Old 12-21-2010, 08:13 PM
  #18  
Senior MemberCaptains Club Member
 
Join Date: Jan 2003
Location: Cape Cod, MA
Posts: 2,375
Default

This is a very interesting conversation... and I just went through a similar thing. It may be far-fetched, but you may want to consider something I did (but didn't plan on!).

Stucco house from 1927, balloon framed with ZERO insulation on exterior walls and a dusting of rock wool in the attic. I put an addition on last fall, and quickly realized that there's no way that even the best mason in the world could match the 80-year old "cake frosting" textured stucco.

So, I bit the bullet and stripped the stucco off, and went with BASF Senergy system. Now, for you guys down south, it's not unusual, but it seems pretty rare for New England.

The house was wrapped in staging, and after the old stucco was stripped, I though, "Hmm, a couple yanks with a pry bar and I could get that sheathing off, and insulate."

I worked like a maniac and pulled each 1 x 10 x 12 board off (by myself!) and pulled R-13 kraft faced into every bay. Renailed all the boards, installed all new Marvin windows, and then the Senergy guys came in and laid their foam (R-12, I think) over it and skimmed.

Before:


Insulating:


Now:


I also removed the god-awful rock wool from the attic (which was an absolutely joyous task), vacuumed the bays, and insulated with high-density fiberglass.

So, on the exterior walls I went from zero insulation to approximately R-25, but it wasn't cheap and it wasn't fun. House is toasty and noticeably QUIETER inside.

I do plan to put Icynene spray on small sections of the cathedral ceiling in the new addition, to avoid having to drill vent into every 12" bay under the exposed rafter tails.

Another thing to consider:
my neighbor has the exact same house as me, and we blew insulation into his exterior walls from the attic... the result? Well, back in the day, they never ran a ribbon board across the open ceiling bays on the first floor, so we unknowingly filled his first floor ceiling with blown-in.

Now, every time he opens or closes a door in his house, insulation puffs out of every recessed light fixture. He's still trying to resolve that...
Chuckster is offline  
Old 12-21-2010, 08:29 PM
  #19  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Sep 2007
Posts: 974
Default Reset

I think it's time to reset what we're talking about. I'm getting advise about not doing things that I wasn't even thinking about doing. Also I'll try to cover everybody's questions.

1) Not talking about expanded spray foam at all. Not an option here. I'm not considering taking down plaster walls and crown molding as an option.
2) This stuff is very similar to the DIY slow rise foam which I've used before. Installation is the same - small hole (or holes) in wall insert tube and slowly fill wall. This stuff expands in the tube as it is mixed so you must fill entirely but less mold pressure issues. R-value is 5.1/inch. 2 x 4 stud walls.
3) Ceiling is already at +R30, windows are double pane.
4) Total utilities cost is $1.50 sq ft/year Probably $.65 sq ft/year for heat.
5) Have run numerous calculations on heat loss, load, etc. R30 ceiling, r-3 wall, replacement windows, etc. Heat loss and Fuel costs are inline with calculators.
6) House built in the late 1950's Cast iron baseboard Oil, fired.
7) Only have about 1600 sq foot of "insulatable" wall after deducting for windows, doors etc.
8) That works out to about 10 of those DIY kits at $700 each. DIY (slow pour) can build too much pressure and make a serious mess....Did I mention I used it before?
9) Wiring is fine in the walls. If any needs to be added will deal with it then. No firestops so that means less holes to drill (from inside or outside).
10) Some have suggested blown in cellulose. Have heard less than great things about it. Can this be DIY?
11) Any options on thermal imaging camera's that cost less than $5,000?
12) 1/2 basement is unfinished. Maybe put up z-channel and 1" or 2" foam boards. But 90% of wall space is below grade so I don't think it will help much.

Still haven't made up my mind. Talking to another contractor tomorrow. First contractor now at $6000.

Thanks for all the input and I'm still looking for more.
Battlewagon is offline  
Old 12-21-2010, 08:38 PM
  #20  
Admirals Club Admiral's Club Member
Thread Starter
 
Join Date: Sep 2007
Posts: 974
Default

Glad to hear it worked out Chuckster. Really quite a job you did there. That balloon framing on your neighbors house probably had you guys scratching your heads about where the hell all the insulation was going. I'm sure his house is quiet though! Fortunately or unfortunately I'm dealing with a stone exterior all the way to the eaves on the outside and plaster walls on the inside. So I've either got to live with it or cut holes inside or outside, fill with insulation and then patch either mortar or plaster.
Battlewagon is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.