Using combo of batts and spray-in?

[jklingel]

For insulating a new house, I am considering a combo of a little sprayed in Icynene-type material, then some kind of batts of mineral wool, either rock or glass. The reason for using the spray-in (and Tyvec) is to seal things up. Using the rock instead of fiberglass almost seemed a no-brainer, but then I read this from the NAIMA web site: Mineral wool is not mentioned. Why? "While spray-foam insulation products can be used to fill gaps and voids, they are not always applied that way and don’t always solve all air leakage problems. Achieving a continuous air barrier with spray-foam insulation can be a very costly solution and something that may not be feasible if framing techniques keep some areas from being completely sealed. If your insulation provider is claiming that they provide a “one-step” solution, look again. For an effective solution to air infiltration and thermal performance, choose fiber glass batt, loose fill or spray-applied insulation with a continuous air barrier outside or a skim coating inside. This is common building practice that is high performing and cost effective." Anyone have any experience w/ such a combo? The all-foam wall sure LOOKS nice; fast & easy to install, good R, etc. Now I am even more confused.

 

[Dawgfan]

I just had closed cell foam sprayed on the inside walls of my shop. The walls are 2x6 with 2x4 lathing and ribbed metal exterior. I installed R19 batts in the remaining wall cavity. I am using OSB on the interior walls.
This is overkill for wall insulation. The spray foam really sealed it up tight. The metal siding use to rattle in the wind and when the door was shut. Not anymore.
Metal siding will sweat in the winter. That is the main reason for using it on my application.
I used metal siding for the ceiling with R38 blown fiberglass overhead. This is a 30 x 40 x 14h ft. shop with 2 - 12 x 12 ft. insulated rollup doors.
I think the sealing up did as much good as anything.

 

[jklingel]

Good to know. Thanks. "Dawgfan". Browns? I see the beat the Giants the other day. Hope springs eternal. later. j

 

[GSSFC]

For insulating a new house, I am considering a combo of a little sprayed in Icynene-type material, then some kind of batts of mineral wool, either rock or glass. The reason for using the spray-in (and Tyvec) is to seal things up. Using the rock instead of fiberglass almost seemed a no-brainer, but then I read this from the NAIMA web site: Mineral wool is not mentioned. Why? "While spray-foam insulation products can be used to fill gaps and voids, they are not always applied that way and don’t always solve all air leakage problems. Achieving a continuous air barrier with spray-foam insulation can be a very costly solution and something that may not be feasible if framing techniques keep some areas from being completely sealed. If your insulation provider is claiming that they provide a “one-step” solution, look again. For an effective solution to air infiltration and thermal performance, choose fiber glass batt, loose fill or spray-applied insulation with a continuous air barrier outside or a skim coating inside. This is common building practice that is high performing and cost effective." Anyone have any experience w/ such a combo? The all-foam wall sure LOOKS nice; fast & easy to install, good R, etc. Now I am even more confused.

With closed cell foam you get 96% effectiveness from the first 2". So installing 2" and then utilizing a less expensive product to meet the R-Value that code officials require. The extra material (fiberglass, cellulose, cotton, roxul) does NOTHING to help insulate the house, it merely adds necessary R-Value. These are called "hybrid" installations. There would be no benefit in using open cell foam or Icynene as the first layer in a hybrid. That foam is installed in 4-5" passes so there would be no room for an additional material.

Tim

 

[jklingel]

Tim: I hope this works. I am responding to a few of your comments. My reply is after the bullets. Thanks for the comments.

With closed cell foam you get 96% effectiveness from the first 2". •• I assume you mean as far as stopping air movement. Yes?

The extra material (fiberglass, cellulose, cotton, roxul) does NOTHING to help insulate the house, it merely adds necessary R-Value. •• Now that one confuses me. R-value is merely a measurement of insulation, so how can you accomplish one w/out the other? Pls explain.

There would be no benefit in using open cell foam or Icynene as the first layer in a hybrid. That foam is installed in 4-5" passes so there would be no room for an additional material. •• Granted, in a single wall. I should have explained above. I will use a double wall w/ space between, like I have now. (2x4, 6" batts, 2x4 for 13" of insulation.) I was thinking of using Icynene in the outer 2x4s only, as I guess it is kind of spendy.

 

[GSSFC]

Tim: I hope this works. I am responding to a few of your comments. My reply is after the bullets. Thanks for the comments.

With closed cell foam you get 96% effectiveness from the first 2". •• I assume you mean as far as stopping air movement. Yes?

The extra material (fiberglass, cellulose, cotton, roxul) does NOTHING to help insulate the house, it merely adds necessary R-Value. •• Now that one confuses me. R-value is merely a measurement of insulation, so how can you accomplish one w/out the other? Pls explain.

There would be no benefit in using open cell foam or Icynene as the first layer in a hybrid. That foam is installed in 4-5" passes so there would be no room for an additional material. •• Granted, in a single wall. I should have explained above. I will use a double wall w/ space between, like I have now. (2x4, 6" batts, 2x4 for 13" of insulation.) I was thinking of using Icynene in the outer 2x4s only, as I guess it is kind of spendy.

The closed cell foam will actually be almost 100% effective at stopping air movement with only 1/2". It is so dense. 96% thermally efficient. Meaning the first 2" you get almost all of the benefits of the product. Each additional inch adds 50% to the original price of 2" (ie 3" is 50% more $$ than 2", 4" is 100% more $$ than 2" etc) but each additional inch may only add 1-2% thermal efficiency.

Regarding R-Value. In my area, the code officials have determined that R-30 is what is required in the roofs or ceilings. To achieve R-30 with closed cell foam you would need 5" of the product. Since we have just learned that the difference between 2" and 5" is mostly cost, one would be advised to install 2" of closed cell foam and then supplement the foam with a less expensive product to meet code requirements. In an area with no codes, simple save the extra money and don't add anything, it will not insulate the wall any better, it is merely there to fill some arbitrary number that code inspector think is required based on 50 year old methods of building science.

I have no stake in your project. I spray foam every day. The more I spray, the more I $$ I make. But I also look out for my customers best interests. If 2" is in the budget I recommend that. If they insist they want 6" of closed cell, that is what they get. I will tell them that is a waste, but if they are convinced that is what they need and are willing to pay, that is what they get.

Here is an excellent article that will help explain it in more detail than I have time to type right at the moment. If you have any more questions, please ask!

http://static.monolithic.com/plan-design/rfairy/index.html

Tim

 

[jklingel]

I have no stake in your project. I spray foam every day. The more I spray, the more I $$ I make. But I also look out for my customers best interests. If 2" is in the budget I recommend that. If they insist they want 6" of closed cell, that is what they get. I will tell them that is a waste, but if they are convinced that is what they need and are willing to pay, that is what they get.

Tim

Tim: Thanks for the link. Will read. I like how you think, trying to keep people's expenses down even though it "costs you". Hope your business does well. j

 

[jklingel]

Tim: VERY good read, that link above. Will investigate further. j

 

[GSSFC]

Tim: VERY good read, that link above. Will investigate further. j

I told my wife I was taking the rig to Alaska for a job, said I would be home perhaps never. That was my plan when I graduated college to move to Alaska but that never happened! I am jealous of the Alaska lifestyle. Good luck!

Tim

 

[Dragster Racer]

This thread prompted me to call for some prices for doing the walls of my 40'X40'X15'. 2" for $6200, or 3" for over $8,000! I would have to live to be a very very old man before that would pay itself back. I did get another estimate that was around $3,800. Even that is tough to justify, but more in the ballpark. I really like the sound of the spray foam, but it is a little rich for my pallet.

 

[rcleaver]

I asked for a price on a new home I'm planning to build, to be similar to SIPS. I got a quote of $43,000!!!!!!!!

 

[GSSFC]

This thread prompted me to call for some prices for doing the walls of my 40'X40'X15'. 2" for $6200, or 3" for over $8,000! I would have to live to be a very very old man before that would pay itself back. I did get another estimate that was around $3,800. Even that is tough to justify, but more in the ballpark. I really like the sound of the spray foam, but it is a little rich for my pallet.

If you use those figures, you could have a maximum of 4800 board feet of material needed. Once you subtract your overhead doors, walk through doors, and windows you will know your total board footage of material needed. Figure about $0.50 a board foot for material cost. So worst case scenario you would be about $2400 for materials (not subtracting any doors or windows). I charge from $0.90-$1.10 per board foot materials and labor. Your contractor that was charging $3800 is probably right in line with an honest bid. The other guys are gouging!

Tim

 

[GSSFC]

I asked for a price on a new home I'm planning to build, to be similar to SIPS. I got a quote of $43,000!!!!!!!!

SIPS are over insulated because they completely fill the cavity. With spray foam that is not necessary and adds substantially to the cost of the bid. I would ask for a revision based on local required R-Value. There is no reason to do anymore than R-19 in the walls and R-30 in the roof/ceiling.

Tim

 

[Dragster Racer]

The low bid was for open cell. He said that the cost on that is $1.50/sqft. Closed cell is more. Your prices seem more reasonable. Not very popular here yet, and I think these guys may be the reason why.

 

[GSSFC]

That is robbery! How the heck do they ever think the product will catch on if they are gouging everyone who wants it? Materials cost is the SAME across the country! That bothers me.

Tim

 

[Matt M PA]

I just got a quote today for closed cell, for a new detached 26x32.....$6066!!!! That's the walls (one of which is almost nothing thanks to 3 garage doors) and the roof.

With things the way they are these days...I'll be doing fibreglass.

 

[GSSFC]

I just got a quote today for closed cell, for a new detached 26x32.....$6066!!!! That's the walls (one of which is almost nothing thanks to 3 garage doors) and the roof.

With things the way they are these days...I'll be doing fibreglass.

Another good method is to use polyiso board. Not the blue stuff, but the foil faced stuff. It takes some time to get a nice snug fit, but you can seal around the edges and seams with cans of foam and get a MUCH better finished product that fiberglass. That is what I would do if I didn't have a spray rig already!

Tim

 

[Dawgfan]

I paid $2 per square foot of surface area for 2 inches minimum of closed cell spray foam. Some areas are a little more than 2 inches. I have ribbed metal walls. There is approximately 1600 square feet of surface area in my shop walls. I paid $3200. I would do it again.

 

[Dragster Racer]

I paid $2 per square foot of surface area for 2 inches minimum of closed cell spray foam. Some areas are a little more than 2 inches. I have ribbed metal walls. There is approximately 1600 square feet of surface area in my shop walls. I paid $3200. I would do it again.

Please do not take this the wrong way, but why do you say that? Is it cost savings? How much do you figure you would save in fuel per year? Are there other advantages that you like? I'm just having a hard time justifying payback at the prices that we have been quoted. If you figure that you spent perhaps $2500 more to go spray, then how many years would it take to save that much in fuel?

 

[GSSFC]

Please do not take this the wrong way, but why do you say that? Is it cost savings? How much do you figure you would save in fuel per year? Are there other advantages that you like? I'm just having a hard time justifying payback at the prices that we have been quoted. If you figure that you spent perhaps $2500 more to go spray, then how many years would it take to save that much in fuel?

It is also a matter of comfort. If you go out to work and it is 60 near the heater but 40 near the walls in a traditionally insulated building how comfortable is that. Compare that to 60 +/- every where with foam insulation.

If you pay on average of $100 a month to heat or cool a shop during the year and cut your fuel cost by 50% (not uncommon at at all). Then that is $600 a year , so 4 years and you have your payback.

It is hard to explain to someone who doesn't have foam, but we have sprayed millions of dollars worth of foam and there is NOT ONE SINGLE PERSON who has said "oh I wish I had used fiberglass instead..." or "next time I'll just use fiberglass".

Tim

 

[Dawgfan]

The spray foam benefit is the air tight seal. The comfort issue and ease of heating and cooling was important to me.
My shop is conventional frame construction with 2 x 4 lathing on the outside and ribbed metal siding. The metal siding will sweat in the winter. The spray foam will prevent the walls from sweating.

 

[Sundowner]

It's nice that this thread came up today, since I just got insulation estimates from my contractor for my home renovation. (2nd floor add-a-level). I had spec's fiberglass bat, but he reccomended that I look into the sprayed in foam. The price shocked even me, and I work in the public sector:

Fiberlgass bat - $3,200

Hybrid 2" thick closed cell with fiberglass batt over top - $10,000

Full thickness open cell insulation - $17,000

Full thickness closed cell insulation - $27,000.

I honestly don't know how these spray foam guys stay in buisness. who in thier right minds would EVER pay that kind of premium? You'd never pay that off, even with my northeastern winters. I wanted the full-depth closed cell foam and I would have paid double the fiberglass bat price to get it. After hearing those prices, I told the contractor to use the fiberglass bat unles she can come back with a MUCH better proce.

 

[rcleaver]

SIPS are over insulated because they completely fill the cavity. With spray foam that is not necessary and adds substantially to the cost of the bid. I would ask for a revision based on local required R-Value. There is no reason to do anymore than R-19 in the walls and R-30 in the roof/ceiling.

Tim

I asked for a quote to match the SIPS purposely to compare the cost with using SIPS. The contractor has a web site where he recommends no more than 2" closed cell foam, with batts to fill up the space if necessary to pass inspection.

Needless to say, I won't be using either SIPS or full thickness closed cell foam.

 

[Dawgfan]

I actually have 2 inches closed cell foam and R19 batts. The walls are 2 x 6 with 2 x 4 lathing. This made for a 7" wall thickness. All the insulation contractor told me over 2 inches on the closed cell is a waste.

 

[jklingel]

This is what I have "learned" (heard) since my origin question, and thanks to all for sharing their experiences. I talked to an energy audit guy about the closed cell outside and 'glass batts inside for a stick house. He said that is not used up here (Frb) because it effectively creates two vapor barriers (visqueen on the inside is a given). He also doubted the need for the spray foam's air-tightness as people commonly use Tyvek for that. Besides, wind is not an issue in most places here, so even the use of Tyvek is questionable. That warrants further research. The local spray foam company charges $1.20/board foot for urethane, and recommends 3-4" on walls and 5-6" on ceilings (for metal buildings). To the $3.60/sqr ft you must add either furring and sheet rock or spraying flame retardant over it, at $2.10/sqr foot. Thus, I don't see me using ANY spray foam in my house. I am sure urethane has its uses, but I don't think it is appropriate for residential stick houses. I have not priced SIPs yet, but the concept has its appeal. Is sticker shock on the way? j

 

[deereman]

I just had Icynene sprayed in about 1 month ago. My shop is 28x40 with 10 foot ceilings. It is pole barn constuction, with all metal siding and roof. Although we haven't had very cold weather yet,(20 deg min so far) I can say that it blocks the wind incredibly, and that is more of a problem here than trying to reach 'R' value. I only had him spray it on 1" thick, and all I can say is what a difference. The building seems so much tighter now and alot quieter. All I have on the ceiling is 3/4 inch polyiso board with foil backing. I taped the seams with foil tape for looks and air infiltration. Without heat for a couple days and nights getting down to about 20-25 deg. the building stays about 48-50 deg. I heat with a wood stove, and I can get it from 50 deg to 70 in about 1 hour. At a later date I plan to finish the walls with barn board, for that cottage look. (plus it will match the bar...) When I do, I don't think I will add anymore insulation, just the wood. I think an air gap is almost as good as insulation, half the battle is sealing the air infiltration, and besides wood heat is free.

 

[jklingel]

Good to hear the Icynene is working for you. We don't have anyone up here that sprays that, and from what I hear/read it is open cell and breathes a lot better than urethane, which eliminates/minimizes the two-VBs problem. What does that stuff cost/board foot? Icynene is what originally got me thinking about having a sprayed/batt combo wall. Maybe next house...

 

[deereman]

It cost me $1/board foot. So total job was $1300 (CAD). The guy that did it is new to this, so it doesn't look the greatest, there are a few flaws. But for the most part, I am really happy, and I still think it's better than batt insulation ( and I didn't have to do anything.)

 

[jklingel]

not bad

$1/brd ft ain't too shabby, and it sure is easier and far more air tight than batts and framing inside a steel building. Does your area's codes require fire retardant over that? That added $2.10/sqr ft when I called on urethane. Maybe the Icynene does not need retardant?

 

[carguykeith]

jk you guys get way colder than we do here in Anchorage but I'm pretty sure we have the same code to follow. I agree R value isn't everyhtign but Tyvek, caulk, and and a couple of cans of The Right Stuff will take care of the wind. Then R19 walls, R50 ceiling (with fiberglass batts) and a well applied vabor barrier (taped outlet boxes and good overlap) will have the building tight as a drum at way less cost than spray.

Just make sure you keep out infiltration and batt insulation works great, lots of 5+ rated houses built every day using the stuff. Not knocking the spray, just saying at least here in Alaska it's not economical.

 

[jklingel]

jk you guys get way colder than we do here in Anchorage but I'm pretty sure we have the same code to follow....Not knocking the spray, just saying at least here in Alaska it's not economical.

Roger that on the cold, but I'll take it over the dampness I am sure you have, and probably more wind off the ocean. We have what is called "still cold". (It's march, and it is STILL COLD!) If Icynene we available and if it did not require fire retardant, it might be the ticket on steel buildings. But, too many "ifs" for now.............

 

[urgti]

I wonder what the cost difference would be between doing a 2x6 construction and batt insulation vs 2x4 and spray urethane foam. Reading the link posted early in the thread its suggested you could even leave off the sheathing and exterior vapor wrap.

I have a question for Tim the poster that applies the foam, what do you think of the Tiger Foam DIY kits compared to having a contractor applied product?

 

[brad d]

The way im building my shop is with R22 rock wool in the 2x6 studs then 1.5" of SM on the outside.. then tar paper over the SM wire and stucco... The SM Will be 1700$ and will go from 1.5' below grade to the top of the wall.

What is your guys take on this option? Its the same way my house was done

 

[brad d]

I thought this was just nus.. what would be the R value of this?

 

[jklingel]

No spray for me, now

I’ve been running numbers on walls (stick house) and am finding some interesting results. I compared the materials cost and R-values of several walls, both double wall designs and a wall designed by the Cold Climate Housing Research Center. The bottom line is, I am not enchanted w/ using much rigid board insulation for my situation. Given that, I have no use for sprayed in foam now. It is just too spendy for what R’s you get out of it, in general. Of interest, the CCHRC wall has an R-value of 21 and a cost of 11 cents/R/sqr foot. In comparison, a double 2x4 wall, with 5 1/2” of batts stacked between them, then 2” or R-tech on the outside (convenience, mostly) has an R of 46 and a cost of 6 cents/R/sqr foot. I prefer to look at the cost of a wall as “per R value”, because R-value is my “return on investment”. The cost differences in single and double wall designs does not get my attention much. I just don’t buy the “too labor intensive” argument against a second wall, but then I am not a contractor and don’t know what folks charge to build and insulate a wall. The time and expense going into a wall is pretty minor compared to other aspects of a house, like kitchens, flooring, a boiler, etc, IMO. Anyone curious about all this should build a quick spread sheet and throw in different wall designs. I have 9 now, and am leaning real hard toward the double wall above, which is very similar to what I have had since 1980. Here is a link to the CCHRC site’s REMOTE wall I referred to above. Click on Snapshots at the bottom to download a PDF file. It sure would be fast/cheap to stand up, if that is of importance to anyone.

 

[GSSFC]

Re: No spray for me, now

I’ve been running numbers on walls (stick house) and am finding some interesting results. I compared the materials cost and R-values of several walls, both double wall designs and a wall designed by the Cold Climate Housing Research Center. The bottom line is, I am not enchanted w/ using much rigid board insulation for my situation. Given that, I have no use for sprayed in foam now. It is just too spendy for what R’s you get out of it, in general. Of interest, the CCHRC wall has an R-value of 21 and a cost of 11 cents/R/sqr foot. In comparison, a double 2x4 wall, with 5 1/2” of batts stacked between them, then 2” or R-tech on the outside (convenience, mostly) has an R of 46 and a cost of 6 cents/R/sqr foot. I prefer to look at the cost of a wall as “per R value”, because R-value is my “return on investment”. The cost differences in single and double wall designs does not get my attention much. I just don’t buy the “too labor intensive” argument against a second wall, but then I am not a contractor and don’t know what folks charge to build and insulate a wall. The time and expense going into a wall is pretty minor compared to other aspects of a house, like kitchens, flooring, a boiler, etc, IMO. Anyone curious about all this should build a quick spread sheet and throw in different wall designs. I have 9 now, and am leaning real hard toward the double wall above, which is very similar to what I have had since 1980. Here is a link to the CCHRC site’s REMOTE wall I referred to above. Click on Snapshots at the bottom to download a PDF file. It sure would be fast/cheap to stand up, if that is of importance to anyone.

Put 1" of closed cell and be done with it!

Tim

 

[jklingel]

Re: No spray for me, now

Put 1" of closed cell and be done with it!

Tim

I assume you are kidding??? If true, then every house in cooler USA would be built that way. I wish it were that simple, but it just ain't so. Have a happy. j

 

[brad d]

Re: No spray for me, now

I am not enchanted w/ using much rigid board insulation for my situation.

Why not? Up here in Winnipeg it gets pretty cold (-33f at times) And here we do 2x6 with R20 or R22 and 1.5 rigid foam on the outside.

 

[jklingel]

Re: No spray for me, now

Why not? Up here in Winnipeg it gets pretty cold (-33f at times) And here we do 2x6 with R20 or R22 and 1.5 rigid foam on the outside.

Brad: First, I calc'd my walls using R-19 batts (normal, here) giving an R-17 WALL because of the wood; etc for other stud walls. Secondly, IMO, the plastics are too spendy. Ex: The "standard" wall here, like in Winnie, is 2x6 w/ 2" of R-tech over that. (Why is 2" cheaper than 1.5" here?) That wall costs $2.38 per sqr foot, has an R-value of 26, and costs 9 cents/R/sqr ft. Not bad, and surely fast to put up, though I have structural integrity concerns with it; a different thread some time. My "ideal" (for now, I think) wall is a double 2x4, as follows. Inner 2x4, empty, for running wires, the odd pipe (hey; it happens, code or not); reinforced vapor barrier on the outside, avoiding vap barrier penetrations w/ each elect box; 9.5" R-30 batts, stacked; an insulated 2x4 wall; OSB; Tyvek; siding. Cost is $2.06/sqr ft, R-42, 5 cents/R/sqr ft. Notice that labor is not included; I work for free, and see my comment above about the "added expense" of an extra wall and insulating it if hired out; peanuts, IMO. Other folks have different issues, and for them maybe a 2x6 w/ R-tech is a home run. Swing, round the bases, get big bucks. Simple.

 

[brad d]

Thats how my old house was (my dads place) two 2x4 walls.. outside to outside was 16" thick... he claimed that it was the first super insulated house in Manitoba.. this was in 1980.. My old man has a thing for R value he invented fiberglass window frames.