Insulation, Radiant and Vapor Barriers - Spray Foam insulation costs

I am thinking of spraying my attice with spray foam insulation.

1. How much does it cost per square foot?

2. Do I need to completely seal the attic by spraying the floors and underside of the roof? or just the attic floor and let the soffets and whirlybird fans vent the attic?

3. Can I spray it over existing loose fill insulation that's the older stuff already in there?



Thanks,

Chris

Hi Chris and welcome to the forum
1. How much does it cost per square foot?
A typical cost will vary by location. If everything is cleaned up and ready for the foam, $1.00 to $2.00 per board foot. That's one square foot, one inch thick. You will need a quote to see what your area rates are.

2. Do I need to completely seal the attic by spraying the floors and underside of the roof? or just the attic floor and let the soffits and whirlybird fans vent the attic?
There are two approaches, attic floor or attic roof (called a hot roof). The more traditional way is to spray or otherwise insulate the floor. Spraying foam has issues of burying lights and electrical. Blown in insulation, I prefer cellulose, is less expensive and much more forgiving if you have to access the area later. As far as the whirlybird, I like to see ridge vents or gable vents. The wb only works with air flow, where passive venting requires less pressure.

3. Can I spray it over existing loose fill insulation that's the older stuff already in there?
No, would be my answer, but I've never contemplated foam over existing insulation. You can however blow cellulose or install batts right over what is there.

Bud

Thanks, Bud.

I know you didn't think this up, but why does everyone always quote prices for one inch of insulation? From what I understand, 1 inch = only R7....

Does anyone ever stop at one inch? Here in Texas, we're supposed to have a minimum of R30-35.

So by my calculations, my 2000 square foot house would need close to $10,000 worth of spray foam?!!!!???? How can anyone afford that?

Again, I realize that this is not a standard that you thought up. :-) I think I may be missing something.

thanks again for future answers!

Chris

You're not missing anything at all, you understand correctly. In fact delivering just one inch is very difficult and measuring what you get short of a fill is difficult as well. I've seen people charged for 4 inches of foam in a 3 1/2" wall or pay for 2 inches and it looks like the rocky mountains, with a lot of valleys.

And your cost calculations are correct as well. Here is my take on anything invented to reduce energy costs. It is priced on what it can save, not on what it costs to produce. Products all too often want to justify themselves based upon a 5 year or so payback. Now it is probably not the dealer who is doing this, more so their supplier. Foam products do not need to be that expensive, but they will remain so until someone else invents a competing product that they want to squeeze into the market. Foam just works so well that they know they can get their price.

Price up some blown in cellulose. It sounds terrible, ground up news paper, but it works extremely well, insulating and air sealing at the same time. For 10 grand you can probably fill your attic solid.

Bud

I cannot say I have priced the spray foam technology and the pricing will vary by location, foam density, etc., but I am about 99% sure it doesn't cost $10,000 for a 2000 sq. ft. home. Most estimates I have heard of are pretty close to the costs of normal fiberglass insulation so I'd have to guess something is wrong with the price figures being used in your calculations.

Call a local spary company and ask fro a free estimate.

I checked the numbers before, and 2,000 square feet at 5" thick equals 10,000 board feet. That's on the low side at $1 per board ft equals $10,000. High side that's $20,000. I just requested a price to quote my customers and it was $1 per bd ft. and I know that is low compared to populated areas of the country.

Never seen spray in foam even close to fiberglass.

Bud

Well maybe it varies by location. I know in NE Ohio a company uses about a 5 R per inch foam and it very close in price to blow in cellulose and fiberglass. The owner actually said most of the cost is labor when blowing into already drywalled cavities in retrofit applications so I assumed in an open attic where the area was already prepped it would be even cheaper. I have never gotten an estimate though so I will defer to you on the subject.

If it is that expensive who in their right mind would ever install it. You can buy 30 sq/ft of unfaced fiberglass R-30 for about $10. Doing the math you could do 2,000 sq. ft. for about $700 in materials. You can buy 40 sq. ft. of R-13 faced fiberglass for about $9 ($600 for 2000 sq. ft.) if you need a vapor barrier and lay the R-30 over it.

Alright fellas, here's the low down on the spray foam for the Dallas Fort Worth area. I finally had time today to call a bunch of spray foam outfits based out of Dallas.

I called 5 different guys, and I got wildly different quotes. As a real estate appraiser, it suprised me that they hadn't spent more time checking out what their competition is doing to make themselves more competitive in the market....but i digress.

I gave all the same info; it's a 1974 built 2000 SF house with about a 6:12 pitch roof with old, insufficient blown-in insulation.

Guy #1 - $14,000

Guy #2 - $3500 - $3800

Guy #3 - $4000 - $4500

Guy #4 - $2/SF (this included taking out the old blown in insulation)

Guy #5 - $1.37/SF for open cell
$1.97/SF for closed cell
-An additional $0.95/SF to take out the old insulation.

All gave the reasonable caveat that this was not set in stone without seeing the actual house.

Guy #1 was clearly smoking crack. He had been trying to conince me about how foam was this big fad, so I think he was really trying to price himself out of the competition and didn't care.

I think that Guys #2-4 all only dealt with closed cell foam, but they didn't go into it (and I didn't know enough to ask them).

Guy #5 said that he'd do the open cell but recommended the closed cell.

All of them also said that they had the forms that I needed to gie to my accountant that would get me as much as possible on the $2500 tax credit. I thought it was really smart of them to mention that, btw. Cuz talking $4000 minus the $1500 (or close to it) really brings that back into the realm of possibility.

I'll be calling more crews tomorrow and will let you know how it goes.

Any thoughts on the bids these guys gave me?

I would love to find a contractor like #2 and #3, but my guess is their price will change when they actually start the job. I assume when you wrote SF you meant board ft. If they are using 5 inches to get in the R-30 to R-35 range, their quotes are in the $0.35 to $0.45 per bd. ft. range.

The only aspect I can see that should lower the price would be the quantity. Small jobs or flash and batt, one inch of foam cost more because of set-up and labor. But a 5" ceiling would be quick, just a lot of foam.

It will be interesting to see what you find.

Bud

I'm in DFW also and am about to start foaming part of my attic. In my case I'm doing a vertical attic wall between one living area where the ceiling is vaulted to 20' and another where the ceiling drops down to 10'. We have a huge draft problem along that wall and foam seems like the only good solution. I ordered the foam online and am going to try to tackle it myself, removing the fiberglass bat insulation, spraying an inch of foam and replacing the fiberglass over it (will probably add yet another layer of fiberglass to bring r value up to over 30). I priced out doing the whole thing with foam and even with doing it myself, it was quite cost prohibitive. The numbers you have come up with are consistant with mine. From what I've read there's no advantage to using foam for the whole job. An inch of foam will provide a very effective air seal and the insulation, fiberglass or any other will provide the needed r value to finish it out.

I added 6 inches of fiberglass bat insulation (unfaced) to my ceilings several years ago and then filled gaps with some blown in cellulose and it made a huge difference for very low investment. Drafts weren't a problem from the ceiling...

Another thought, and I haven't thought it through completely... Houses in this area don't usually have ANY vapor barrier in the ceilings. That could just be low budget construction, but there could also be a good reason for it... I can't figure that stopping the passage of moisture out through the ceiling would do too much harm, but it might add to the summer time humidity level inside and make the house harder to cool comfortably.

If I were you, I would consider foam in vertical areas where you need to stop drafts and ceiling areas where space is limited and you need the higher r-value per inch. Otherwise I would just add enough fiberglass or cellulose to what's there to get the r-value up in the 30-40 range.

Also remember, unless you can get an energy star certification, insulation generally doesn't have a significant effect on the market value of the house. I'm a real estate agent and buyers won't pay extra for anything they can't see. Your paybacks are the lower utility bills and added comfort.

Doug M.

Good post Doug,
About vapor barriers in Texas, they would go to the warm side of the insulation or if that is not easy to define, heat in winter and ac in summer, then omit the true VB and just make sure the air barrier is well sealed. My link on vapor retarders won't come up right now, but that is a topic to review.
Now back to the op.
Doug's comments on real estate values emphasizes the importance of taking pictures of your improvements. Some day down the road the house will be sold, then being able to show and tell what was done will add to the value of the home, along with the lower energy bills.

Bud

Bud, Wish you were here... Good insulation is a somewhat new concept in this area. When I first moved to Texas (from New York) 26 years ago you could only find a handful of companies that did insulation in the yellow pages. Now there are hundreds and a high percentage of them don't know what they're doing.

Our houses are designed to shed moisture rather than retain it and keep the cooler air in the bottom of the living space. In the few weeks of winter we get every year we suffer with dryness, drafts and cold floors and it's really tempting to try to fix those problems forgetting that some of what causes them is what keeps us cool in the 9 or 10 months of warm/hot weather. Sometimes it's better to simply put on a sweater and heavy socks...

Not to get this thread too side tracked, but in regard to resale value even pictures don't help much: The person selling your house is most likely going to be the buyer agent who knows no more about it than the buyer and couldn't care less if the buyer chooses it or one of the next 50 they're going to see. If you are lucky enough to have a buyer agent who's mechanically savvy, he/she will also probably be skeptical, as I am, of mechanical upgrades because so many of them are done wrong. You aren't going to have a couple hours of face time with me to prove otherwise so I'm going to err on the side of caution. Good example: I recently almost sold a house where the listing agent featured a brand new upgraded furnace. It looked great and my buyer was very impressed. Unfortunately, when we looked a little closer (and I got out my tape measure) we found that the new furnace made it impossible to remove the water heater which was in the same closet. :eek: Value of upgraded furnace? NEGATIVE!

When it's time to sell, call in a staging expert (or an agent like me who provides one ;)) and put your money into looks.

Doug M.

just as a quick support for those outrageously expensive numbers that are being tossed out there with some dispute, here is one online company that sells product for DIY:

Commercial Building Fireproofing Foam (http://www.fomofoam.com/productlist.htm)

If you will notice, Bud's numbers are actually good compared to these prices and from a little research myself previously, these numbers are not all that out of whack with others out there in internet land.

Two things I don't understand Doug:

1) How can drafts ever be a good idea if you are trying to efficiently heat or cool a home? I don't understand how adding a vapor barrier could ever be a bad idea. If you have the proper equipment and it's sized correctly moisture should not be an issue once the living space is properly insulated.

I have also read that fiberglass batt insulation is roughly 15% less effective at any given R-Value vs. foam because of so much air penetration.

2)By adding insulation to the home you will lower energy bills and that would make an effect on a potential buyer's opinion wouldn't it? If most homes in a neighborhood are constructed in very similar fashion and you make yours more energy efficient and thus have 20% - 30% lower energy bills won't a customer see that during the home buying process and factor that into the equation? I know when I bought my house and did a self energy audit I was able to negotiate the price of the house down as it was well below current insulation recommendations.

I'm not an expert in the field and maybe b/c I live up north and we have different climate trends I am wrong but I have never seen anyone recommend no vapor barrier.

Shane, An improperly placed vapor barrier can cause condensation to form and soak conventional forms of insulation, rendering them useless and setting up a prime breeding environment for mold.

We live in 2 different worlds. Much of the year in your climate you fight to keep humidity IN your living space. A vapor barrier between the inside surface and insulation does a great job to help and presents little risk of condensation building up even in the summer, when it's in the wrong place, because there is air movement on the open (attic) side of the insulation that allows it to dry out once the season changes. In our warmer more humid climate, we fight, most of the year, to get humidity OUT of our living space and even with the best equipment it can be a big problem. Most of the year our outside humidity isn't too far from comfortable so a vapor barrier provides far less benefit to begin with and placement on either side of the insulation involves big condensation risk depending on the season so houses have traditionally been built without it. Trends have started to change over the last decade with the invention of products like Tyvek which let moisture pass in one direction and block it in the other. Most builders are putting such a product on the outside walls these days, but we still don't normally put anything in attics because the condensation risk is just too high.

Back to the original topic: Closed cell foam is a bit of a different animal because damp air can't get through it to reach a cool surface and condense. There's no danger in using it in an attic around here that I can see, but there's still only a short part of the year in this area when the vapor stopping ability is of any benefit and a long part of the year when it's a disadvantage. At best it's a wasted investment and at worst it will decrease comfort more than it will improve it. Add another 6 inches of fiberglass or cellulose to compensate for the "15% less effective" and you're still thousands of dollars ahead.

Regarding resale value, again, we're in different worlds. Heating and cooling energy usage isn't as critical here as it is in your climate and most of the homes in this area were built within the last 30 years or less so they have at least minimal insulation. I've never seen a home that had a deficit that was significant enough to justify negotiating a lower price, especially between otherwise comparable houses in the same neighborhood. On the other side, I have yet to see a seller be able to prove energy savings from added insulation or upgrades that was great enough to warrant above market pricing other than, as I said yesterday, documented Energy Star certification. Interestingly, though many homes in this area that were built in the 2000's had Energy Star certification when they were built, it's almost never featured when they're re-sold so the added value is lost.

Sorry this was so long and hope I didn't sound harsh. I moved to Texas from the North (upstate NY) 26 years ago and was initially appalled by the building practices I saw here. Then I learned...


Almost forgot, houses here are also designed to facilitate air movement with open floor plans, high ceilings and HVAC vents that blow down from above. In warm weather all that increases evaporation from the skin and makes it feel cooler. In winter, it just makes it feel cold.

Doug M.