Spray foam insulation

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sjdavis's picture
sjdavis
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Spray foam insulation

Hi,

Does anyone have experience or knowledge about various spray foam products?

We are insulating the wall cavities of our home.  Spray foam insulation seems to be the best ROI  for this application.  The only issue is that each installer seems to use a different product.  We're not sure about advantages and disadvantages of each.  Things like reliability and air quality are very important.

One installer uses Triploymer from C.P. Chemical Company, Inc.

Another company uses the commercial grade foam from Applegate Insulation.

I'm familiar with Applegate because they're based in Michigan, which is where I live, and have a solid environmental reputation.  They made the cellulose that is in the attic

But foam is a very different product and not sure which is the best choice.  Any opinions are welcome.

Thanks,

Stu

 

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Re: Spray foam insulation

SJDavis,

I live on the Texas Gulf Coast in a home raised on pilings (hurricane flood zone). A few years ago we removed the fiberglass insulation under the floor and had a contractor spray foam insulation. Even though the contractor was a friend of mine and we got a great deal on the job, I have to say that I am very disappointed with performance of the insulation. I have not detected any savings in my a/c or heating bill, and comfort-wise, the floor pretty much feels the same as the traditionally-insulated floor throughout the year .

I don't recall the chemical or trademark name of the foam used, but it was supposedly the best available in 2008. One other thing, even though we hung plastic sheeting to catch overspray, it still took about a month to clean up the mess from the spraying process. If I had to do it all over again, I wouldn't bother with the extra expense or hassle of spray foam insulation.

Your situation might be different, but I just wanted to offer my opinion for what it's worth.

Best...Jeff

 

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Re: Spray foam insulation

I put a spray foam on the concrete block crawl space during a remodel last year.  Mainly I was interested in sealing up small openings to keep out rodents and to add some insulation to the crawl space, which did not have any before.  We have exposed plumbing down there with heat tapes and insulation wraps, but they were inclined to freeze in winter.  I did not apply this to the underside of the floor, only to the vertical concrete block walls.

Due to tight space, it was a lot of work to get the stuff to go on correctly, but now that it's done, I'm pretty happy with the results.  The crawl space consistently stays within 10 degrees of the upstairs temp, even though I do nothing at all to put heat down there.  I do not need to run the heat tapes for the plumbing at all, even when the outside temps get to 30 below zero or more.  Small cracks and openings are closed up, so no drafts get in, and neither do the bugs and mice. 

I like the foam because it stays where I put it, and did not require furring strips or any other things to keep it in place.

The stuff I used was called "foam it green" and came in two large tanks with hoses, sprayer heads and even a tyvek suit to protect myself from getting the stuff all over me.

 

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Re: Spray foam insulation

The only thing I can add is that as far as 'spray foam' insulation goes you can get closed cell or open cell.

IMO you want to get an open cell foam because it will 'breath'. Closed cell foam can cause condensation build up and without any way for it to evaporate you can wind up with mildew.

 

 

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Re: Spray foam insulation

Hmm. I don't know if it is the same stuff, but I used some aerosol expanding foam to seal up pipe holes in the floor under my bath that mice were getting in. The little blighters chewed their way through it!

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Re: Spray foam insulation
james_knight_chaucer wrote:

Hmm. I don't know if it is the same stuff, but I used some aerosol expanding foam to seal up pipe holes in the floor under my bath that mice were getting in. The little blighters chewed their way through it!

Have you tried some steel wool?  The little buggers hate it.

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Re: Spray foam insulation

I had this done about 3 years ago and while it seemed expensive at the time (~3X the cost of fiberglass batts) it has been wonderful. I used a company that sprayed Icynene, a soy based product that expands as it sets up and then the excess is trimmed off. I did the entire third floor of my house (while it was gutted) before drywalling. The difference before and after was profound; not just in insulating properties but also in sound deadening. It's turned a cold drafty house into a snug and efficient home. One huge advantage of the spray foam is it is also airtight, unlike other forms of insulation.

Mike

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Re: Spray foam insulation
ao wrote:
james_knight_chaucer wrote:

Hmm. I don't know if it is the same stuff, but I used some aerosol expanding foam to seal up pipe holes in the floor under my bath that mice were getting in. The little blighters chewed their way through it!

Have you tried some steel wool?  The little buggers hate it.

Boric acid is another trick.  Cockroaches hate it as it is highly toxic to them.  It also deters termites.  Spraying framing and subfloors with it puts off many types of pests.  It is a bit toxic to humans, so you don't want to go nuts with it.  I had an infestation of cockroaches in my kitchen.  I made a solution and sprayed everywhere they were likely to be.  And I used tub calk to seal up the cracks after.  No more roaches.

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Re: Spray foam insulation

There are several spray in place foam products available.  Urethanes and isocyanurates are two popular types.  They have similar insulating properties.  Expect about an R30 or slightly better in a 2x4 bay.  Isocyanurates are slightly better but degrade a tiny bit over time.  Both should be  applied by trained people.  Everyone on the job should be wearing an approved respirator (NIOSH or some such 2 micron filter).  Dust masks from the hardware store are NOT acceptable.  Inhaled particles will expand inside your lungs and become a permanent part of you.  Dust masks, despite what the hardware store clerk tells you, do not stop the dangerous forms of particulates.

Sprayed in foams have some other advantages over fiberglass bats.  Remember also that fiberglass bats are rated under ideal conditions.  In the field, moisture can condense inside bats rendering them useless.  Also, convection currents can form in and around bats that will conduct heat away from the envelope.  And bats by themselves are not air tight.  It's also not unusual for horizontally hung bats to come loose and droop out of floor joists.  Fiberglass must be installed correctly or its effectiveness is greatly diminished.  Wherever foams are sprayed, they'll stay put.

One problem with foams is that they will expand into j-boxes and other enclosures.  These need to be masked before the foam is applied.  The same is true of heating ducts, vents, and plumbing.  Another problem with foam is UV light.  Sunlight will degrade urethanes fairly rapidly.  Flashing or euscusheons (sp?) will help to prevent this.

Sprayed in foams form a moisture barrier.  This means your house might need an air to air heat exchanger as part of your ventilation system.  If your windows fog up on cold days, there's too much humidity and mold and dry rot will soon follow.  An air to air heat exchanger can be coupled into the return on a forced air system for greater effect.  Or a dehumidifier can be placed nearest the affected areas.

Foams have a big up-front cost, but you get what you pay for.  Sprayed in cellulose is a less expensive next best thing.  It has some of the same physical properties such as sealing and staying put, but the R-value is lower.  It's also treated to be flame retardant and repellant to pests and fungi.  Blown in dry cellulose or fiberglass for attics is okay if you have no mechanicals in the attic.  That stuff is miserable to work around and it often winds up getting pushed out of the way which leaves gaps.  This is personal experience talking.

If I were to build, I would make foam insulation as important a cost consideration as the foundation, not as an afterthought.  Also 2x6 studwall is not necessary with foam.

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Re: Spray foam insulation

One thing you'll want to make sure of is that you have no leaks in your envelope. I just discovered a couple of leaks in my attic last week near my chimney during a rainstorm. Hopefully a little roofing cement will do the trick. Will find out after tomorrow's monsoon. Better to get those leaks fixed before you spray foam.

In any event, I'm getting my attic spray foamed hopefully in the next month or 2. I'll post my experience here once it's done.

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Re: Spray foam insulation

Durangokid;

Excellent overview.  Wish it had been available when I was looking for a product for my application.

The kit I purchased included a 3M respirator (looks something like a gas mask) along with gloves and hooded tyvek coveralls.  This obviously added cost to the purchase, but made me comfortable that the vendor is concerned about more than just unloading it's product on the customer. 

Mine was a small job, took about 45 minutes.  Anything like insulating a house I would definitely hire out.

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Re: Spray foam insulation

If you are insulating the wall cavities of an existing home, then an expanding foam will blow out the interior walls. There is a slow rise foam product but you have to pour it in from the top.

I would take a hard look at dense pack cellulose (or dense pack fiberglass). Cellulose contains borax, which works as a fire retardant and also a pest deterrant. Both products can fill every nook and cranny in the wall cavity if installed properly, like foam. Not the same R-value as foam, but much more practical for existing walls as far as I know. Closed cell foam does have the advantage of being an air/vapor barrier, although dense pack cellulose can significantly reduce air infiltration (which is a huge cause of heat loss).

As discussed in previous posts, spraying closed cell foam can lead to moisture problems. You need to understand how to deal with moisture in your climate (what works well in Maine would not be smart in Alabama or Colorado), but everyone will have the same problem with roof leaks. Closed cell foam sprayed in the attic ceiling will conceal roof leaks (the water can't get thru the vapor barrier), so when when the water finally works it's way downstream into the living space you will have a very unpleasant experience trying to trace the source of the leak.

Also make sure the wiring in the walls are not overloaded before insulating. 14 gauge wire will overheat above 15 amps, and insulating a wall with knob and tube wiring is a serious fire hazard (they stopped using knob and tube wiring in the 1930's). AND WEAR PROTECTIVE GEAR when dealing with foam, DurangoKid's last post pretty much nails it on specifics.

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Re: Spray foam insulation

I've got an estimate for foam in my attic under the roof and the vendor recommends removing the existing fiberglass blown-in and bats that are on the attic floor. Should I pay extra for this? Will it help the attic become a more efficient climate zone? 

In GA, looking at closed cell, green foam.

 

Found this article....   http://www.buildingscience.com/documents/digests/bsd-102-understanding-attic-ventilation/files/BSD-102_Understanding%20Attic%20Ventilation_rev.pdf

with this quote:  

High density spray foam insulation due to its impermeability properties can be installed 
directly under roof decks in any climate zone without any additional provision for 
vapor diffusion resistance - including Climate Zones 5 or highe

 

 

great link too

http://www.buildingscience.com/documents/information-sheets/high-r-value-wall-assemblies/high-r-wall-08-spray-foam-wall-construction/?searchterm=foam

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Re: Spray foam insulation
GeoJoe wrote:

I've got an estimate for foam in my attic under the roof and the vendor recommends removing the existing fiberglass blown-in and bats that are on the attic floor. Should I pay extra for this? Will it help the attic become a more efficient climate zone? 

In GA, looking at closed cell, green foam

 

THe Green Clsed Cell Phone is from DOW Chemical, I think.  I just had my attic done with it as well.

I now have 2" Foam on the attic ceiling and R30 Fiberglass on the attic floor.

No way would I remove the fiberglass insulation. I think there is great benefit from having the fiberglass insulation in place, but  working less hard than it was before.

This morning, it is 0 degrees out, but my attic is 46degrees. My fiberglass insulation is working against 46 degrees instead of 0 degrees.

Foam is amazing! particularly for ceilings.  I have not found it to make much difference for floors, however.  At least in terms ofthe percived warmth of the floor.

Thx,

John

 

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Re: Spray foam insulation
GeoJoe wrote:

I've got an estimate for foam in my attic under the roof and the vendor recommends removing the existing fiberglass blown-in and bats that are on the attic floor. Should I pay extra for this? Will it help the attic become a more efficient climate zone? 

High density spray foam insulation due to its impermeability properties can be installed 
directly under roof decks in any climate zone without any additional provision for 
vapor diffusion resistance - including Climate Zones 5 or highe

 

No, you shouldn't remove it. I have some old "crap" insulation in my attic and I asked 2 different contractors about leaving it or removing it, and they both said to leave it.  It doesn't hurt anything. Not sure why he recommends moving it?

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Re: Spray foam insulation

Getting the envelope leak free is a great suggestion Joe.  We held off for a year on attic insulation until we could locate and fix a leak.  Our issue was ice damming in a poorly ventilated attic.  We had the roof replaced, added soffit and ridge vents, and R-60 cellulose.  The attic is now well ventilated and insulated.  The results are good.  

After that I started researching wall insulation and learned about foam, including the newer hot-roof concept in attic foam installations.  Hot-roof as opposed to the well ventilated design I just installed.  If I were to do it again I'd probably get the roof deck sprayed with good foam like you're doing.  While both roof/attic insulation designs have good results, foam is also an air seal.  Once the envelope is sealed you have more control over ventilation.

The wall foam is being installed in a few weeks.  The foam is the non-expanding Tripolymer.  We're also getting the rim joists done with an open cell w/ vapor barrier Icynene.  Rim joist installations are expensive on their own, but very cheap if they're already coming to do the roof deck.  If you have a basement, you might want to ask the company to throw it in for a small bit extra.

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Re: Spray foam insulation

We had closed cell "hard" foam sprayed onto the crawl space interior block walls and under the floor of this small house just about 1 year ago.  The cost was high, but the contractor did take a bull calf as partial trade. Wink The results have been tremendous; elimination of drafts, rodents, cold floor.  Electric savings of 10-20% year round.  Coupled with applying thick poly over the crawl space soil, the overall comfort level in this small house has increased substantially.  Highly recommended.

Long time member, first time poster.  Hi Ya'll!

 

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Re: Spray foam insulation

Our attic gets pretty hot! There is a nice layer of insualtion between the ceiling joists protecting the downstairs, but nothing between the roof joists. We live in SC and although we added gable fans and an attic fan (solar) we wonder if insulation under the roof itself will just trap the heat or keep it cooler up there. Any ideas, people?

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Re: Spray foam insulation

Spray it!  (The deck that is.)  This has been covered in other places ,( http://www.peakprosperity.com/martensonreport/alert-qe-has-lit-fuse?page... ), but you will be better off with the entire attic deck spayed and the ventilation system shut down.

Yes.  That's right.  A sealed attic system.  It doesn't seem to make sense, but it works.  Especially in SC!

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Re: Spray foam insulation

I investigated having our attic foam sprayed, but decided against it due to its exorbitant price -- 6-8K for our house --  and that was for only a couple inches of foam. In addition, they spray directly under the wood roof sheathing which would hide any future leaks that may occur. In addition to that, the concept of sealing off the ventilation system of your attic is a relatively new idea with foam and still controversial.

Whether or not to ventilate a crawl space has been a controversial issue. Most building codes presently require installation
of vents to provide ventilation with outside air, but a recent symposium on crawl space design organized by the American
Society of Heating, Refrigerating and Air Conditioning Engineers concluded that there is no compelling technical basis for
crawl space ventilation requirements. However, if the crawl space is not ventilated, it is crucial that all of the crawl space
ground area be covered with a durable vapor retarder, such as heavyweight polyethylene film. Other concerns that must be
considered before eliminating ventilation to your crawl space are discussed in the Builder's Foundation Handbook
published by the US Department of Energy.

Insulation[PDF]

Our home owner's insurance would be affected if we used foam.

We went with an all-natural spray-in insulation called UltraTouch, which also comes in batts. I did it myself (2 feet for an R-factor of 60+) for a fraction of the cost of foam and the results were immediately noticeable. We no longer shiver and my heating bill/consumption has gone down even though we keep our temp at around 72F. If I was a Rock Star with money to burn on a new mansion, then I might splurge on the foam stuff; but for all practical purposes, there are really good insulation systems out right now that won't break you and are just as, if not more, effective.

I also investigated the use of sheep wool as insulation which apparently has health benefits to Humans due to its natural ability to filter out toxins. Then again, the price was a factor. We've got sheep wool rugs instead. Maybe Captain Sheeple can give CM'ers a discount on his wool.

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Re: Spray foam insulation

Another consideration is to install a radiant barrier.  I'm not sure what's more effective, a radiant barrier or a spray foam roof deck?  But, I have read that a general guideline is to use a barrier where it's hot most of the year and insulation where it's cold.  If that's true, and heat is the problem upstairs then a radiant barrier may do the trick.

A radiant barrier and insulation protect against different forms of heat loss.  The barrier prevents greater than 95% of radiant heat from entering the envelope.  You could look at companies like AtticFoil.com.

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Re: Spray foam insulation

Let me clarify a few things. We need the storage up there, so the attic--which is not air condtioned and has no ducts for A/C--is completely separate from the main floor of our ranch home. There is just a pull-down stair to the area, but it is huge.

We have no basement. We have no garage. We need the storage as cool as possible. The gable fans and attic fan made a HUGE difference in the attic temps, but will adding insulation between the roof joists help or hurt the storage temps?

To recap:

* A/C comes from underneath the house, so it is not running through the attic (heat pump)

* We don't nned to blow insulation into the attic floor, because the center section has plywood subflooring (we have plenty of loose insulation between the ceiling joists, with some air space)

* So the question is how best to insulate the underside of the actual roof. I've installed fiberglass foil-backed insualtion in my attic in NY, but that was mainly to keep the heat IN. Here, I mainly want to keep the heat OUT.

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Re: Spray foam insulation
safewrite wrote:

Let me clarify a few things. We need the storage up there, so the attic--which is not air condtioned and has no ducts for A/C--is completely separate from the main floor of our ranch home. There is just a pull-down stair to the area, but it is huge.

We have no basement. We have no garage. We need the storage as cool as possible. The gable fans and attic fan made a HUGE difference in the attic temps, but will adding insulation between the roof joists help or hurt the storage temps?

To recap:

* A/C comes from underneath the house, so it is not running through the attic (heat pump)

* We don't nned to blow insulation into the attic floor, because the center section has plywood subflooring (we have plenty of loose insulation between the ceiling joists, with some air space)

* So the question is how best to insulate the underside of the actual roof. I've installed fiberglass foil-backed insualtion in my attic in NY, but that was mainly to keep the heat IN. Here, I mainly want to keep the heat OUT.

Yes the foam under the roof sheathing would reduce temp considerably; but there are much cheaper radiant barriers you could install on the underside of your roof that would do the same thing as the foam.

http://www.ecofoil.com/Applications/Attic-Insulation

 

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Air Quality

Anyone want to chime in on a home that is sealed up tight with spray foam, etc., and the air inside the house...as in air quality. Is that an issue?

I remember seeing this video on the Digest about making your own fresh air with 3 plants. It sounds as if this may help against a home sealed up tight. I did buy the plants/seeds. We'll see how the air inside the home feels in the spring...

Unfortunately, I still am getting a water leak through my chimney into the attic...no spray foam insulation until the spring for me. Frown

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Re: Spray foam insulation

safewrite, in my non-expert opinion, a simple radiant barrier is going to be the cheapest and easiest solution.  A radiant barrier only keeps heat out.  It would keep radiant heat from building in the attic.  Since you already have insulation between attic and living space, the demand on that insulation would be reduced with a radiant barrier.  So theoretically, attic would be cooler and living space cheaper to cool.

It should be easy to do since your attic already has plywood flooring.  The foil just gets stapled to the rafters.  Although some companies offer a product that is insulated with bubble wrap, most people say it's not necessary and just install the basic foil.

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Re: Air Biofiltration Planters
joemanc wrote:

I remember seeing this video on the Digest about making your own fresh air with 3 plants. It sounds as if this may help against a home sealed up tight. I did buy the plants/seeds. We'll see how the air inside the home feels in the spring...

Hey Joe,

Thanks for the video that you posted. I have a lot of interest in this subject, and some experience in its application. I bought a book back in the 90's titled: How to Grow Fresh Air: 50 House Plants that Purify Your Home or Office by B. C. Wolverton and it inspired me to do some tinkering with air biofiltration planters around the house. Here are some charts from that book with information on various plants and their ability to remove various pollutants from indoor air:

One thing that wasn't mentioned in the video was that if you pull air through the root zone of these tropical plants with a small fan, their air filtration capacities can increase up to 50 fold. During the construction of my house, I built-in some planter shelves high up on the walls to serve as air biofiltration planters. You can see parts of two of these planters above the double doors in these pictures:

My intention was (is) to fill these planter boxes with lightweight media (like expanded shale) and create wicking beds for tropical plants (watering these plants by hand is a pain....). I want to embed a perforated 6-inch PVC pipe in the soilless media and attach a small fan on one end to pull air down through the media. I've had some trouble getting the fan-pipe system together, so right now I just have the plants in pots, sitting within the planter shelves. 

We have 65 plants throughout our home (just on the inside) and though it can take 40 minutes or longer to hand water all of them, my family doesn't suffer from many of the respiratory conditions that others living in this area experience. Now if I can just get all our plants in self-watering, air biofiltration planters.....

Best....Jeff

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Re: Spray foam insulation

Insulation directly beneath the roof sheathing is a bad idea.  It greatly increases the heating of composition shingles and reduces their life span proportionately.  Insulation should go into the joists (horizontal framing members) first.  If you must insulate the rafters, as in a finished attic, you must put an air gap between the insulation and the roof sheathing, install soffet vents, and ridge vents.  Vents in the gable ends help ventilation.  A thermostatically controlled fan blowing into the attic is better still.  The outside air will cool the fan, by the way.  I've worked in attics that have gotten as hot as 140 degrees in mountainous areas that normally stay cool.  The roof sheathing gets to hot to leave your hand on.  We had to quit at noon.  Too hot.  So the heat issue is real.

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Re: Spray foam insulation

Thanks everyone for your responses on insulating my attic. I know from experience up north that you need an airspace inbetween foil-backed insulation and the actual roof, or there will be problems with moisture build-up. (Our next door neighbor was a general contractor and came over to advise us...we ended up redoing half the attic because we'd left no air space, so believe me that is one lesson I will never forget!)

X-rayMike, is that just plain foil with no insualtion? Really? I had no idea such a product existed. Thanks for the info on  http://www.ecofoil.com/

As to putting insulation ON the roof, under the shingles....well, we just replaced the roof so that's not even crossing our minds. But we did go with white shingles to try and deflect some of the heat. We have 100-degree F summers and some of our neighbors actually have black roof tiles, which srtikes us as about as smart as a black interior in a car in Dubai.

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Re: Air Quality

Joe,

When you install spray foam and seal up your house, you have to change some things about the way you manage fresh air and humidity.  To keep this short, the bottom line is that you must get humidity out using exhaust fans every time you shower or produce a bunch of steam.

Secondly, I installed a fresh air intake on both of my AC units.  Some portion of the return air is pulled from outside to keep the air in the home fresh and circulated.  On the more advanced systems, I have the thermostat kick on a small exhaust fan that exhausts air to the outside at the same time new air is being brought in with the fresh air intake.  This creates negative pressure, and allows the house to circulate fresh air into the home.  

Odds are, your HVAC guy may look at you funny if you ask for this, but MEP engineers do this regularly for medical facilities.  I started doing it after I built my first large medical clinic and can give you more details if you want.

 

Rector

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Spray Foamed my existing walls

I finally got some relief in my house. I had my walls spray foamed last week. I had no insulation in my walls, except for my dining room. Needless to say, it was quite drafty and expensive this winter. My furnace was running all the time. Just to give you an idea, my oil furnace would run for 4 minutes, then pause for 8, before running again. Now, at the same temperatures, both inside and outside, the furnace runs for just 3 minutes, and the pause time is anywhere from 15 minutes to 25 minutes. Now THAT is a big difference! And this is with very little insulation in my attic floors(the next project). I ran my woodstove the other night and the entire house was warmed up very nicely.

Here's a couple of pictures. The blue tape indicates the stud. The insulators drilled three 1/4" holes per stud bay(for the most part), 1 at the knee level, 1 at shoulder level and 1 at the tippity top under the ceiling. The foam that came out of the hole below is not such a good thing. The idea is to try to get foam just to the open hole and not pour out of the hole. Too much foam may blow open the wall. Luckily that did not happen to me.

Here's another wall with the shoulder level and top holes showing. Notice the extra holes at the top. In certain bays, they had to drill extra holes because the house framing was different.

And here's another wall I've already patched up. The holes in my walls were fairly smooth for the most part. I have plaster walls and the insulators told me that is better all around for a project like this.

On the other side of this wall, the insulators were pouring in the foam, which is 212 degrees, and they hit a carpenter ant nest. It was every ant for itself. It was quite a sight!

If your thinking of spray foaming, take it from me, go for it! I admit, it is very pricey to do, but I would guess this should pay for itself in a couple of years.

joemanc's picture
joemanc
Status: Martenson Brigade Member (Offline)
Joined: Aug 16 2008
Posts: 834
Energy Audit

I had a contractor that works with my utility company come out on Friday to perform an energy audit on my home. Even though I have done quite a bit of fixes myself, including spray foaming my walls(see post above), I wanted to have them see what I missed. One of the things they did was to run a blower door test and found several more leaks I missed.  They sealed those leaks with caulk and spray foam and then re-ran the test, and the test indicated the airflow "leaking" out of the house was reduced by another 10%. I'm now in the normal range for homes in terms of air leakage. I can only imagine what that number would be had I not spray foamed my walls. I'm still working on my attic insulation, which the tester indicated would get my air flow numbers down further, and I may end up doing the rafters underneath the basement ceiling. That should really tighten things up and knock down my heating costs even further.

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