# foam insulation



## fishhead (Jul 19, 2006)

I was talking to my cousin yesterday about adding insulation to my old house and he suggested using sprayed in place foam. He said there are types of foam that don't expand much so the risk of cracking the sheetrock are minimal.

Does anyone have any experience with this type of insulation? Can I do it myself?


----------



## Windy in Kansas (Jun 16, 2002)

Some time ago on one of the hst forums someone posted about using a Dow Froth-Pak foam insulation. As I recall he had good results with it but it may have been in new construction. I seem to recall him mentioning warming the components during use.

http://www.building.dow.com/global/
http://www.touch-n-seal.com/twocomp.htm


----------



## artificer (Feb 26, 2007)

Are you talking about drilling a hole in the wall, and filling a closed cavity? If so, let the pros do it.

I've been gutting the house a room at a time. When I have exposed bay cavities, I put in 2" of the pink foam, and use Great Stuff to seal it in. More labor intensive than getting it done, but a lot cheaper.

Quote for spraying the shed was $2 for the first board foot, and $1 for each board foot after that. So 2" thick foam would be $3/ft^2, compared with about $0.75 with the foam board.

Michael


----------



## fishhead (Jul 19, 2006)

Yes. I'm still trying to figure out a way to add insulation to my old house walls from the outside without creating a second vapor barrier.


----------



## SolarGary (Sep 8, 2005)

fishhead said:


> Yes. I'm still trying to figure out a way to add insulation to my old house walls from the outside without creating a second vapor barrier.


Hi,
I think that blown in dense pack cellulose would be a good option. When done right, its very good stuff, and much cheaper than foam. Dense packed cellulose also has some infiltration resistance.
The book "Insulate and Weatherize" by Harley has a good how-to on dense packing in walls.


I read somewhere that some installers will not use foam in walls because of the chance that it will leak out into the living area and make a mess. If you have ever used "Great Stuff" polyurethane foam in a can, you know how bad its its to get off anything.

Gary


----------



## PlowGirl (Nov 16, 2005)

The stuff in the can is not the same as the professional spayed in place foam. I have a straight sided quonset style building and had it sprayed. The foam doesn't expand that much, not like the canned stuff, and a professional knows just how thick to spray it. It can be painted over or drywall plastered as soon as it cools down as it's put on warm. 

One caveat, it has a flashpoint of 600 degrees so exposed foam can become a fireball very quickly.

The really great thing about foam, no draft whatsoever. It's probably more airtight than you'd want your insulation to be.


----------



## HermitJohn (May 10, 2002)

I couldnt argue with its effectiveness, but the price, OUCH! However if you are serious about insulation and trying to build or retrofit to super insulation standards, its the way to go I think. There are various formulations including one made from soybeans, some expand, some dont, depending on your application.


----------



## fishhead (Jul 19, 2006)

I tried the cellulose one summer but it's an owner built home and I think the guy was wearing beer goggles when he built it. The insulation is random so some cavities have insulation and some don't. Every cavity we checked had some insulation.

I may just have to rip off a row of siding and check EVERY cavity and just fill the empty ones with cellulose.

Will blown in cellulose compress the fiberglass? That would make it much simplier because then I wouldn't have to try to figure out which ones to fill. I would just fill them all.


----------



## SolarGary (Sep 8, 2005)

fishhead said:


> I tried the cellulose one summer but it's an owner built home and I think the guy was wearing beer goggles when he built it. The insulation is random so some cavities have insulation and some don't. Every cavity we checked had some insulation.
> 
> I may just have to rip off a row of siding and check EVERY cavity and just fill the empty ones with cellulose.
> 
> Will blown in cellulose compress the fiberglass? That would make it much simplier because then I wouldn't have to try to figure out which ones to fill. I would just fill them all.


Hi,
I think that you will be able to get some cellulose in the cavities that already have some FG in them. The way I understand it, you use an about 6 ft long and about 1.25 inch diameter clear plastic hose taped to the end of the main blower hose, and start by pushing the hose in as far as possible in one direction, then as the cavity fills you pull the hose down so that the hose does not jam with cellulose. I'm told that with some practice you can hear when its just about to jam. Then you push the hose in the other direction and repeat the process. 
From what I've read, it may be best to use two holes in each stud cavity -- one high and one low. This would also take care of any blocking that might be in the wall -- but maybe this is overkill?

I think that its worth getting as much cells as you can in the cavities that already have some FG in them. 

Here are some detailed blowing cellulose "how to" accounts:
http://www.builditsolar.com/Projects/Conservation/WallCellulose.htm


Gary


----------



## Explorer (Dec 2, 2003)

Wouldn't that collapse the fiberglass and make it ineffective?


----------



## ET1 SS (Oct 22, 2005)

I used 'touch-n-seal' foam, a spray-in-place foam using two components.

I sprayed 1.5 inches of foam onto our walls and roof.

It was fun!


----------



## ET1 SS (Oct 22, 2005)

The 2 component epoxy foam that I used is not flammable.


----------



## Intrigue (Jun 11, 2008)

You can purchase DIY foam kits - example Tiger Foam

http://www.tigerfoam.com/index.php

Cellulose (paper) insulation is great for the attic but it does have some drawbacks for wall cavities. It will settle over time and if it gets wet it will become useless mush.

If you are re-doing the exterior (like new siding), the best thing to do is to attach foam panels to the wall before the siding. You want the panels that are "breathable" so that vapour doesn't get trapped and rot your walls. The big advantage to insulating the exterior is that it covers the thermal bridging over the studs. As you all know, the studs themselves are a significant area of heat loss, doesn't matter what type of insulation you have between the studs.

The blown-in insulation between studs (where they drill holes) is actually a waste of a lot of good money. Not only is it labour intensive (read that as expensive) but in older homes there is no vapour barrier, and it's the air infiltration that is your worst enemy. When we retro'd our house, I sucked it up and removed the whole interior wall covering (old plaster/lathe). Attached additional 2x2s to extend the thickness of the studs, upgraded the electrical wiring, packed with good new fiberglass, plastic vapour barrier, and installed new sheetrock. We also did the exterior with 1" foam panels. We needed to add an air exchanger to our forced air system because the house was so tight afterwards.

Might as well do it right the first time.

If you want to use the DIY foam, you could just add an inch (because it is excellent air-proofing) and pack the rest of the space with fiberglass.


----------



## SolarGary (Sep 8, 2005)

Intrigue said:


> You can purchase DIY foam kits - example Tiger Foam
> 
> http://www.tigerfoam.com/index.php
> 
> ...



Hi,
I would respectfully disagree on cellulose for wall insulation not being a good choice. When cellulose is blown in at higher density (dense packed) it will never settle and has a very good R value per inch. Cellulose is also a fairly effective air infiltration barrier (in contrast to blown in FG). 

I think the way you did your house is great, but that extensive a job is not an option for most people. 

The book "Insulate and Weatherize" by Bruce Harley is very good on blown in cellulose. Bruce is an engineer and builder who has been working in this field for many years -- he makes a very good case based on a lot of data and practical experience for cellulose being a very good choice wall insulation. Its also (I think) the best all around "how to" book on insulating out there -- well worth the price if you are going to do an insulating project.

You can also go to the Fine Homebuilding "Breaktime" forum and read through some of the past material on cellulose vs FG in walls -- these are the professionals who build homes and install insulation.

http://www.homeenergy.org/archive/hem.dis.anl.gov/eehem/92/920510.html

http://www.builditsolar.com/Projects/Conservation/WallCellulose.htm

Gary


----------



## fishhead (Jul 19, 2006)

Intrigue said:


> You can purchase DIY foam kits - example Tiger Foam
> 
> http://www.tigerfoam.com/index.php
> 
> If you are re-doing the exterior (like new siding), the best thing to do is to attach foam panels to the wall before the siding. You want the panels that are "breathable" so that vapour doesn't get trapped and rot your walls.


Where would I find breathable insulation panels?

As far as the cellulose compressing the FG and negating the insulation value that would be okay if it's replaced with the cellulose. I've read that when cellulose is properly installed the shrinkage is insignificant. The problem may come when it's installed too loosely.


----------



## ET1 SS (Oct 22, 2005)

Each type of insulation has it's own pros and cons.

Two 'tricks' are left to use homeowners.

One is to carefully avoid thermal bridging.

The other is to use two different insulation methods, so that the over-all between the two combine to make a perfect insulation.

Spray-on foam is structural. It seals all air draft and makes your shell into a monolithic structure. But it is expensive. I used a thin layer of foam, then added nine inches of batting.

Together they complement each other.

Very few thermal bridges, no drafts, and no settling.


----------



## Kevingr (Mar 10, 2006)

We're getting the dense pack cellulose installed in our house next week. They will be taking the siding off at the top and bottom of the wall cavity. They then push a rod in from the top and the bottom to compress the FC in the wall cavity (if any) then they blow in the dense pack. They are also adding another 8" to the ceiling, sealing up any breaks in the walls to the attic and redoing the bathroom vents through the roof instead of through the soffit like they are today (air blows in all winter long!). The also need to build more dams in the attics (I have three) to add the insulation and seal up some wall cavities that are not sealed properly (long story there!). They will also do a blower door test before and after. 

4 man team 4 day project, 2 story house 1100 square feet per floor, 100 year old farm house that has had some remodeling over the years. Total cost is just under $5400. I thought that was pretty reasonable considering all the work they will need to do. Next year we plan on residing the house and putting insulation on the outside under the new siding.

Neighbor took off all his interior sheet rock, sprayed all the wall cavities with Great Stuff (the can's), then put tongue and groove cedat on the inside. It's about a 900 square foot house. Said he used 100 can's of foam. It's pretty warm and toasty in his place in the winder. No drafts! Not like mine!


----------



## ET1 SS (Oct 22, 2005)

Kevingr said:


> We're getting the dense pack cellulose installed in our house next week. They will be taking the siding off at the top and bottom of the wall cavity. They then push a rod in from the top and the bottom to compress the FC in the wall cavity (if any) then they blow in the dense pack. They are also adding another 8" to the ceiling, sealing up any breaks in the walls to the attic and redoing the bathroom vents through the roof instead of through the soffit like they are today (air blows in all winter long!). The also need to build more dams in the attics (I have three) to add the insulation and seal up some wall cavities that are not sealed properly (long story there!). They will also do a blower door test before and after.
> 
> 4 man team 4 day project, 2 story house 1100 square feet per floor, 100 year old farm house that has had some remodeling over the years. Total cost is just under $5400. I thought that was pretty reasonable considering all the work they will need to do. Next year we plan on residing the house and putting insulation on the outside under the new siding.


Wow! that sounds like a big job. 





> ... Neighbor took off all his interior sheet rock, sprayed all the wall cavities with Great Stuff (the can's), then put tongue and groove cedat on the inside. It's about a 900 square foot house. Said he used 100 can's of foam. It's pretty warm and toasty in his place in the winder. No drafts! Not like mine!


100 cans !?!?

If you buy it in the 600 sq ft kits it is much cheaper.


----------



## Intrigue (Jun 11, 2008)

In Canada we have an organization called CMHC (Canada Mortgage and Housing Corporation). They are the government agency that insures new home warranties and insures low down payment mortgages. Anyway, that's not the point. The point is that this organization does a LOT of research on building technology. They sponsor a lot of grants to look at all kinds of building methods form insulating basements, to insulation to structural stuff. 

We first looked at building a new home but decided on a 150 year old 2200 sq ft Victorian house (on lakefront and 15 acres). I did a ton of research on all kinds of things like insulation, HVAC systems, septic systems, etc, etc. For example we had to install a Category 2 septic system. But back to insulation.

Cellulose insulation will not stop air penetration. The best it can do using high density premium brands is about a 30% reduction (compared to no insulation) and that's just good enough. These days with high energy costs, you MUST stop the cold air from getting inside. All these small leaks can add up to having the equivalent of a large hole in your living room. Of course, if you also burn a woodstove or fireplace that isn't outside intake vented, another huge waste.

There are only two ways to stop air flow. One is to use a air blocking insulation and foam is the only one that will do the trick. Or use a physical vapour barrier (like heavy plastic and sealing) on the warm side, which usually means the interior facing surface. Just blowing insulation between the studs is an improvement but really not up to par.
If I was going to spend $5400 on having cellulose blown in, then I would spend the extra on at least having foam.

If you are already renovating the interior and replacing stuff like to wiring and upgrading windows, then it's really worth it to replace the wall covering and add the insulation, electrical, plastic and sheetrock. Maybe a big job, but we did our house ourselves, room by room, estimated total cost about $2000.

If you are planning to replace the exterior siding (like vinyl siding), consider opening the wall cavity by removing the plywood as well. You then able to spray an inch of foam, fill the rest with insulation, put fresh new plywood sheating, add an inch or 11/2" foamboard, then the exterior cladding of your choice (vinyl, Hardiplank, wood, whatever).

The whole idea is that the insulation companies are great at sales pitches about adding insulation. They talk about foam aqnd cellulose and R-Values ( a useless number), but the real truth is that you must stop the air.


----------



## Kevingr (Mar 10, 2006)

The air will be stopped from the outside when the siding is replaced using Tyvek. Most of my house already has plastic on the inside from when the house was remodeled in 1986. It has many holes in it from what I can tell from some inspections I've done, great care was NOT taken to keep that plastic tight. But since the electrical, plumbing and sheetrock are only 22 years old there's no sense in taking that down when we NEED to address the outside. The money is better spent in filling the wall cavities to capacity and addressing the air infiltration from the outside as it should be when we address the outside of the house. 

Personally, I'm not a fan of foam. Yes, it's a great insulator and yes it's a great wind stopper. But it's so permanent. I'm of the mind and opinion that something should be made so that it can be altered or repaired. The idea of having a wall cavity filled with solid foam so that I couldn't stick a wire down it if I wanted to bothers me to some degree. Maybe it's a control issue.


----------



## WisJim (Jan 14, 2004)

You should have a vapor tight inner layer to prevent moisture from getting into the insulation and the building structure. I have seen lots of rotting houses because they didn't do this, especially homes that added sheet insulation under new siding.


----------



## ET1 SS (Oct 22, 2005)

This foam:

http://www.touch-n-seal.com/twocomp_kits.htm

Can be bought from:

http://www.efi.org/wholesale/


----------

