Having foam blown into walls

[EatenByLimestone]

I was talking this over with the wife and finally it came down to cost, which I have no idea on.

If I remember correctly, a few have had it done to their houses. Around how much did it cost and are you satisfied with the results? Would you do it again or go with a different product like cellulose?

Thankya,

Matt

 

[woodgeek]

If I had empty wall cavities, I would do densepack cellulose: cheapest, effective and no outgassing concerns.

 

[GENECOP]

I used ICYNENE foam installed in several areas of my house, it is the tightest most appropriate insulation for odd shaped, barrel, cathedral ceilings, etc...not inexpensive but worth it IMO....The only drawback is future wire pulls, pipes, any changes after the fact are difficult to execute after the foam sets up.....

 

[DBoon]

If you have uninsulated walls, getting insulation blown-in will add a huge amount of comfort to your house, and you will wonder why it took you so long to get it done.

 

[EatenByLimestone]

Most of my walls are empty, but in some spots I had some vermiculite that had fallen out the bottom of the wall and was topped with cellulose. Other spots have fiberglass. It's a bit of a hodgepodge.

 

[sloeffle]

I had the soy based open cell foam sprayed in my 2 x 6 exterior walls when I put my addition on my house. He sprayed closed cell foam around my rim joist and I do not smell any outgassing to this day. The cost of doing cellulose was about the same and I was concerned about settling over time. I am very happy with the performance of it compared to the rest ( batt insulation ) of my house.

If I were to build a house today I would use foam insulation again.

 

[peakbagger]

I have friends who did it many years ago on an ancient farmhouse. They heat with very little wood a year and it stiffened up the structure considerably. They have done a lot of renovations since then and have never seen any traces of issues when removing the interior walls except that the foam makes things more difficult.

The issue with offgassing is strictly related to the firm doing the work and the level of training. There are two chemicals that need to be mixed in the correct proportions and at the correct temps, if that is not done offgassing can occur. With the older systems. one component was less expensive then the other so a contractor would cut corners by using more of the cheap component.T his caused bigger bubbles and more coverage but also outgassing. Most firms requires licensed contractors with training.

Next house I would go the flash and bat method but for an older home without access to the wall cavities I would go foam.

 

[woodgeek]

Certainly the foam guys dis the cellulose guys and vice versa. I am a humble homeowner. Decades ago lots of foamed walls emitted carcinogenic formaldehyde, and low density cellulose walls settled a bit. Now both of these problems are solved.

Densepack cellulose doesn't settle. Worst case scenario is it does, and your energy consumption goes up 5-10% decades from now.

With foam, the formulations are still obscure...the names of the formulations and their suppliers seem to change every few years, old formulations get vilified, banned and replaced. It is frankly really hard to tell what is what. Even the soy based foams and water blown foams...what % is petroleum derived? Icynene seems to be the best in terms of formulations (there are several), but they charge cadillac prices. I'm aok with a little PU can foam here or there, or outside my conditioned space (e.g. attic), but all the exterior walls of my house....I want to know what is in that stuff, and what comes out for years later (that doesn't smell).

And what is the worst case....your foam product gets mixed improperly and stinks like fish for months, doesn't set properly or shrinks inside the cavity (with loss of airsealing and insulation value), or the install goes perfectly but your brand gets declared toxic and banned 10 years from now, etc.

Never going to happen with cellulose.

 

[peakbagger]

The reference to toxic formulations is primarily related as I discussed to bad application by crappy contractors. At one point EPA banned spray foam until they could investigate the issues and when they did they came to the same conclusion, installed correctly there are no issues with properly applied foam.

Cellulose has had its issues, predominately settling and moisture issues where it absorbs moisture and encourages mold. I think it comes down any product misapplied or done shoddily can have issues.

 

[woodgeek]

The Formaldehyde-Urea foams from the 70s remain banned by the EPA, but many other foams with very similar (and often undisclosed) formulations remain in use. Try to find out exactly what is in icynene or 'tripolymer' and you will have a hard time.

I am no chemo-phobe, and have worked routinely with teratogens and radioisotopes, and I think 98% of organic food is a crock. But if I am going to pour hundreds of pounds of reactive organic compounds into the walls of my one and only house where I spend 5000 hours a year, chemicals whose slightly different formulations have been and are banned, and which can remain volatile in my walls for months or years if they are not mixed properly or react at the right temperature, well then, there I balk.

Again, I would prob do my rim joists and sills with something that I researched carefully (and could always rip it out if absolutely necessary at a later date), just not every square foot of the exterior wall cavity.

 

[sloeffle]

I asked the cellulose guy about about the settling and he said they add water and a chemical to it to help with settling. I asked what happened when the water evaporated out and he really didn't have an answer. The idea of spraying a wet insulation onto OSB also did not sit well with me either. The cellulose they were going to use is made out of recycled newspaper and I asked what it used as fire preventative and he said it was a proprietary chemical.

IMHO both cellulose and spray foam have good points and bad points. You just need to pick your poison.

Instead of selling the wool from my sheep maybe I need to market is as "organic chemical free insulation".

 

[woodgeek]

To give cellulose the same roasting....

Your cellulose guy was not doing densepack (>3.5 lbs/cu ft), he was doing wet-spray, which is done at lower density (and is thus cheaper from a material point of view). Densepack cavity fill is sprayed in dry, using a higher pressure than possible with big-box rental store machines. My guy had a truck mounted (and powered) machine and 100' of hose. There is no adhesive required to prevent settling.

(broken link removed to http://www.energyoutwest.org/eow_library/__presentations_docs/_wx_technique/Dense_Pack_Cellulose_Insulation.1.pdf)

As for the chemicals...there does have to be a fire retardant and mold/pest inhibitor. This is either ammonium sulfate or boric acid, typically 15-20% by weight (!!). The other 80% is shredded newspaper, mostly post-consumer recycled. There is a concern that either of these chemicals can be corrosive, and attack wiring or fasteners, but there are no reports of major consequences that I know of. Both compounds are solids, don't vaporize, and are not particularly toxic. You can make a different assessment. Folks seem to be more comfortable with boric acid, which is also less corrosive, so 'sulfate free' cellulose is available for a 10% upcharge.

After I had my rim cavities densepacked, there was a little gray dust around (I assume the installers vacuumed) and a slight 'ammonia' odor (I got a 50:50 mix of ammonium sulfate and boric acid). I cleaned up the dust and the odor was gone after a couple days.

I still contend that I know what is in the cellulose, it isn't chemically reacting to create other compounds, and it isn't volatile.

I would not want to get either cellulose (and the acids) or sprayfoam wet.

 

[laynes69]

Our home had urea-formaydahyde foam injected in the walls in '79. From what I've seen when remodeling, I don't know if I trust foam. The foam has shrunk in every wall I've opened up. Some has remained solid, but some when touched turns to dust. From what my father said, if it wasn't mixed correctly it would produce all sorts of problems. My father and grandfather owned an insulation business with foaming walls with urea foam, but when it was banned, that was it. I know foam carries a nice r-value, but if I didn't have to open things up to insulate, I would choose dense packing cellulose. It's funny around here, very few people know of dense packing. Having foam in some of our walls still, requires us to open things up and remove it. I've ended up airsealing the walls and putting in R-19 batts of fiberglass in each room.

 

[dja950]

Next house I would go the flash and bat method but for an older home without access to the wall cavities I would go foam.

Flash and Batt method can be dangerous in cold northern climates due to condensation and moisture issues.

 

[peakbagger]

Flash and batt is not dangerous in cold climates if installed properly. The key is that the flash has to be thick enough so that the inner face of the foam is above the dewpoint temp in the coldest weather. Its back to the same issue with any insulation system, improperly installed insulation can be problematical no matter what it is.

 

[dja950]

Flash and batt is not dangerous in cold climates if installed properly. The key is that the flash has to be thick enough so that the inner face of the foam is above the dewpoint temp in the coldest weather. Its back to the same issue with any insulation system, improperly installed insulation can be problematical no matter what it is.

Like I said it can be dangerous, I've seen the carnage from it not being done correctly. In my climate at least 2 inches is recommended.


If doing flash and batt, which can be a very economical way of insulating a house well, please please please make sure you do your homework and make sure you use the correct thickness of closed cell. Moisture and condensation problems in the walls behind drywall can go unnoticed for a long time and do a lot of damage in the way of mold and many other things. Johns Manville, making of batts and bought corbond spray foam, recommends 2 to 2.5 inches of closed cell when doing flash and batt.

 

[mellow]

Got a question, I have the old (1950's era) black cloth covered copper electric lines still in my walls, I have not blown anything into my walls because a few have said I need to upgrade to romex before doing so, is that true?

 

[dja950]

Knob and tube wiring needs to be replaced, yes.

 

[mellow]

I don't have knob and tube, this was after that. Mine is cloth covered romex, looks like this:

 

[EatenByLimestone]

I've always considered that stuff to be fine. I have that in the family cabin that was installed in '52 and it is still in good shape. When the walls are open I replace the 14g with 12g to make future upgrades easier, but if the walls are closed I don't worry about it.

 

[Dave A.]

I have that. And fiberglass batts were installed along with it when built. Pretty sure that's what romex was like in the 1950's and into the early 1960's. Iirc the copper itself is covered with plastic.

 

[woodgeek]

That what my 1960 romex looks like. Ok, not burnt and crumbling. I never gave it a second thought.

 

[Dave A.]

Ok, not burnt and crumbling.

Guess I missed that. Still not real clear about what's being shown.

 

[mellow]

Mine isn't covered in plastic, it has the cloth wrap on the outside then cloth wrap with a paper around the wires, they seem to be in good condition but I just don't like to move them to much as you can hear that crunching sound when you do so. Everyone I had talked to was saying that the chemicals in the spray insulation would eat the cloth romex.

 

[Seasoned Oak]

I was talking this over with the wife and finally it came down to cost, which I have no idea on.

If I remember correctly, a few have had it done to their houses. Around how much did it cost and are you satisfied with the results? Would you do it again or go with a different product like cellulose?Thankya,
Matt

I compared the cost of those do it yourself foam kits with blown in cellulose and the cost of the foam kits were astounding. Fibreglass is out ,lots of bad experiences with it,it shrinks,doesnt pack tight around outlets wires ect. Now board foam is another story,not a bad return there if you can use it,but for empty wall cavities blown cellulose is hard to beat. Been using it for 30 years now.