Pour It In or Pump It In?
By Tom Inglesby
Decisions, decisions. Is pour-in insulation the way to go or should you hire the guys with the foam-in-place truck? This question turned into one of the most heated exchanges we've had at Masonry.
Long before there was foam-in-place insulation, there was granulated pour-in material to add to the cells in CMUs. Today, they exist side-by-side although proponents of each will tell you one is vastly superior to the other. So which is better? Let's take a look and see if we can come to an understanding of why and when one is better.
Last year we had a feature on foam insulation that covered the basics of this medium and how it works and is applied. This time we'll look this time at factors that might make a contractor choose foam over loose fill material.
Tailored Chemical Products, Hickory, N.C., produces Core-Fill 500, an insulation material for use in commercial and industrial construction that has excellent thermal and acoustical properties. It is a two-component system consisting of an amino-plast resin and a catalyst foaming agent surfactant. These two components, when mixed in the proper ratio and propelled by compressed air, produce a foam insulation having the appearance of shaving cream.
Mark Huckabee, national sales manager for Tailored Chemical likes to refer to the product as an "integral insulation." As he puts it, "Our product, along with loose fill, is considered an integral insulation system when used with concrete block. It's appropriate in any situation where you are filling concrete block from six to 12 inches, and up to 16 inches on occasion. It provides many benefits over other products, of course, and is the most specified and installed block insulation in the United States for commercial projects."
On the other side of the desk is Eric Moeller, sales and marketing manager for Grace Specialty Vermiculite, a part of Grace Construction Products. Moeller is based in the San Francisco area, far from the Grace home office in Cambridge, Mass. It is believed that vermiculite was originally observed nearby in Worcester, Mass., in 1824. When exposed to a flame, the mineral would expand into a variety of fanciful forms resembling small worms, hence the name vermiculite, or worm breeder.
For about 100 years after its discovery, vermiculite was not of commercial significance. In 1923, a deposit in Libby, Mont., was developed for commercial production by the Zonolite Company of Chicago, Ill. Grace Construction Products entered the vermiculite business in 1963 with the acquisition of the Zonolite Company.
Moeller addresses one of the big issues with insulation, thermal mass. "Thermal mass is what determines your heating or cooling loading. It's what really helps maintain temperatures of structures. It's the thermal mass, in the masonry, that ends up providing most of the heat sink for retaining the heat. What vermiculite or perlite does is completely fill the cavities of the concrete masonry unit (CMU). That's required both from an insulation standpoint so you don't have the radiant heat going out and also from the standpoint of providing some stability in terms of the moisture that is always associated with CMU."
No matter what concrete you're talking about, it's porous to some degree, and the vermiculite or perlite, another pour in insulation, is treated with either an asphalt-based or silicone material to make it water repellant. It provides a method for getting the water, once it's in the wall, out. "That's one of the biggest advantages over foam," claims Moeller.
Huckabee counters that foam-in-place offers a better "R-value" than loose fill. "From a performance standpoint, the R-value is significantly higher than published R-values of loose fill insulation." He begins. "Typically you will find R-values on a per inch basis for ours and similar products of 4.6-4.9 per inch. Typically we see loose fill product in the 3.0-4.0 range."
Jack Temple III, vice president of Tailor Chemicals adds, "That means, in a standard lightweight density block, foam-in-place insulation will typically have an R-value 20-40 percent higher than any loose fill product perlite, vermiculite or Zonolite in the same block."
Looks like we are going to have some strong disagreements here. If vermiculite, as the typical pour-in material, doesn't insulate as well as foam, what is its big advantage? After all, adding insulation is done... well... to insulate. Of course, there are other values besides R-values involved.
Acting as a fire retardant, for example. According to Moeller, "In terms of fire code, masons grout either sections or levels and if they're using foam, that grouting provides a break. Foam also is not fire proof. Foam companies have improved the flame spread with foam, but foam will end up either combusting or melting under fire and it does create gas. Pour in insulation meets the UL classification ASTM E-84 that means zero flame spread, zero fuel contribution and zero smoke developed. It's the highest fire classification you can get. No foam I'm aware of even comes close to that."
To which Temple responds: "Our foam does not melt. One of the reasons for this misconception is that a lot of people call these 'foamed plastic' and plastic melts when burned. These products are not plastics. Our foam has, per ASTM E-84, a flame spread of zero and a smoke developed rating of five. I can't speak for other companies but when Core Fill 500 is injected into a two-hour (fire) rated masonry unit, we can increase the fire rating to four hours which is the same as loose fill can do, not perlite, but vermiculite and Zonolite."
Seems like things are heating up in our discussion. Moeller adds some information to the fire. "Another big advantage of vermiculite is, if you do have a fire, even if it's a spot fire, because vermiculite is completely non-combustible you may have charring or damage but the insulation will be the same as it was the day it was poured in. If you use foam, you can be sure that, under the heat of a fire, the insulation capability will be compromised even if you don't have flame damage. There's no way to get it out of the wall so you're going to have to pump more in and hope for the best."
Before we get burned out, let's move on to another hot topic installation. Masonry is becoming a year round activity in almost all areas of the country. Can both pour-in and foam be done in all types of weather?
Huckabee says there is no reason to shy away from foam-in-place due to climate it can be used in the winters of Minnesota and North Dakota as easily as in the summers of Florida. "Our largest dealer is in Florida where masonry is a major way of building and Phoenix is another hot area for us," he puns. "Our insulation goes into as much as 75 percent of the commercial retail and school building work in Arizona."
Since vermiculite is a loose granular material that gets poured in as the wall goes up, if workers can work, vermiculite can be poured. As Moeller says, "It comes in a four cubic foot paper bag that weighs around 25 pounds. You tear the bag open and pour the material into the wall. It's a pretty simple process. The mason tender just takes the bags up and empties them right into the top of the wall before the cap is put on."
On the other hand, foam-in-place requires expensive equipment and certified crews to install it. "We strongly recommend having properly trained applicators and experienced people on the job site," explains Temple. "That is very important. Because the foam is actually manufactured on site, you need competent people to do it, making sure the density of the product meets specifications and that it is installed properly. Having it installed properly means you're going to get 99 percent fill of the wall."
So foaming isn't something the average mason contractor is likely to do. "When we go out to the job site we drive up with an equipment package that's in excess of $80,000," Temple says. "On board heaters maintain a constant temperature of the material and that enables us to install the insulation even in sub freezing temperatures we can work 365 days of the year."
Huckabee comments, "We get calls all the time from masons saying they are unfamiliar with the product and 'I've got a job here and they want this stuff, can I buy it from you and install it myself?' The answer to that is typically "no," unless they want to become a certified installer from one of the manufacturers."
The ease of use that vermiculite can claim helps offset the added cost factor vermiculite is generally more expensive than foam. Moeller admits as much, "In terms of an installed cost per foot, it is more expensive than foam. The other biggest downside is, because it's free flowing, if you end up doing retrofits to those walls, and you're not careful about cutting into them, it's just like an hourglass the stuff will just pour out."
Huckabee agrees, "The bad thing about a loose fill material is it must typically be injected as the wall is going up. So at any point in time if a door is cut into the wall, or a window put in, or pipe chase is run, and the wall is cut into, the loose fill insulation will run out. That's probably the biggest complaint you'll hear from a mason contractor "I pour it in and something happens that I have to cut into the wall, and the product pours out and it's next to impossible to get it back in there and to make sure it's 100 percent full."
There are ways around that. Grace provides stickers that go on the walls during installation of Zonolite Masonry Insulation (ZMI) to advise people that if they're going to cut into the walls, they must put a seal around the cut. "But that never happens," Temple interjects. "They might recommend these things, but it never happens and it's one of the biggest reasons why architects and contractors were yearning for a different type of system 20 years ago when we came out with foam-in-place for commercial applications."
While pour-in is poured in as the wall goes up or near the end before the cap is placed, foam is done after the wall is completed, all the cuts are made and the masons are on their way home. "That's the beauty of our product," smiles Temple. "Typical installation guidelines are that all the block is up, roof's on, doors are put in, windows are put in, pipe chases are put in, electrical conduits are put in. Everything is in place and then we come in and seal up the building, seal the voids. It allows us to completely fill every void once everything is in place. Then if someone goes back and adds something like a door or window or backs into it with truck the insulation stays in place and does not come out."
Moeller brings up another factor: sound. "Both products, foam or pour-in material, provides other things besides thermal insulation. In an apartment complex situation, for example, you've got sound transmission, which is a big issue these days. Vermiculite has a pretty good sound transmission rating of 51. That's equivalent to cutting out about half the noise that would normally be transmitted through that CMU unit."
As with any heavy competition, certain "facts" get carried over generation to generation. The pour-in guys tell you foam melts; the foam guys say, "No, it doesn't!" Huckabee points at pour-in and says, "It is common knowledge that loose fill, over time, will settle in the wall. We have done numerous applications 5-15 years after a building was insulated with loose fill material and we had to insulate the walls 1-4 courses from the top where the loose fill had settled over time."
Of course, Moeller disputes this, saying, "Today's pour-in insulation won't settle. That's a big point. It settles less than one-quarter of one percent, and that was tested under extreme conditions. Once it's in there it's not going to move around or change very much."
Huckabee returns to the cost factor, adds the "hassle factor," and says, "Some mason contractors would tell you, even if it costs them more money, they would use foam-in-place insulation because the headaches and the hassles of having to pour that insulation into the top of the wall."
So we called up a mason contractor, Ed Davenport of Davenport Masonry, Holt, Mich., and asked him, "Which would you choose, foam or pour-in?" Being a nice guy, Davenport hedged his bet, saying, "It would depend on the job." Come on, Ed, what would you prefer?
"Well, if the foam is done correctly, I think it is better," Davenport admits. "We find the problem with holes in the wall allowing loose fill to run out; that's not going to happen with foam. And pour-in material is not very pleasant to work with, requiring masks and such to protect the workers from inhaling the dust. And when you factor in the labor costs, hassles and material costs, foam is usually less expensive than pour-in. So, I have to say, foam wins when it is done correctly."
About the Author
Tom Inglesby is a San Diego-based freelance writer whose work has appeared in numerous online and print publications. He is the winner of the Construction Writers Association's 2002 Boger Award for Special Reports.