As of Friday 5 December, my GARN is now heating my home.  I have a series of web pages at www.pennbrookfarm.com/garn/garn.html

Feel free to take a look.  I just uploaded a bunch of photos today, but ran out of time to upload the videos.  I have 8 videos of the first burn cycle.

Jim K in PA

www.pennbrookfarm.com/garn/garn.html

 The videos are uploaded and ready for viewing.  They are on the last page, www.pennbrookfarm.com/garn/garn8.html

Jim,

      Great photo's of your installation. I feel like I need to comment on the insulated pipe to the building. IMHO, I have some concerns about spray foanimg pipe in the ground. I think the potential for failure due to moisture is very high. I will be curious to know what your results are on performance down the road. I am also curious to know how much cost it saved you over pre-insulated twin pipe. Do you or anyone else have any experience with this method?

Hello Kenny and Jim,

 I do not have personal experience with sprayng foam directly on the tubing in the ground, but know there is a wealth of information which will substantiate the wisdom of doing this.  The foam used must be 'closed cell foam', and knowing a bit about Jim I am certain he chose the correct polyurethane closed cell foam for this application.  There was a study done in Canada with various insulations used on the outside of buildings, at-and-below grade (as I recall, down 2 feet!) Sprayed, closed-cell polyurethand foam was sprayed on the concrete building, above grade and down 2 feet, then back-filled. In one instance grade sloped away from building, in another case grade was purposely sloped toward the building. To the best of my recollection the building was done such that there were three sets of thermocopules, two sets placed at two levels below grade and one set placed just above grade. At a given level or depth, sets of thermocouples were placed (a) out a couple feet from the building, (b) at the 'outside' of the foam, (c) at the junction of the foam and the outside of the concrete foundation, and (d) on the inside of the concrete foundation. The building was monitored daily for 2.5 years. Everything performed excellently. This was determined both by the performance of the building and I believe by cutting the building apart 2.5 years later. There were no breaches in the adhesion of the sprayed polyurethane foam to the concrete.  I will see if I can find the link to that article.  Obviously, since this was done in Canada, and since the foam was above grade to 2 feet below grade, there were numerous freeze/thaw cycles over the 2.5 year experiment which certainly tested the integrity of the adhesion of foam-to-concrete ---- and Jim's foam job will virtually all be below the frost line I presume, so his system should have less stress than the Canadian test.  I will see if I can find the link to this interesting article. Additionally, I have seen other applications where the pipes were laid in a trench and then foamed.  Darn clever. VERY excellent use of the closed cell polyurethane foam, I would believe.  Sincerely,  Hankovitch in Wisconsin

 Hey Hank!  If you do find a link to that article, please post it here.

 Kenny - the foam is as Hank describes above.  It is a two part, closed-cell polyurethane.  This is not the stuff you can buy at HD or Lowes, or even the stuff you can buy in overpriced kit form.  The application equipment includes heated tanks, heated lines, very specialized mixing nozzle on the gun, etc.  The material cures in seconds, and supports hundreds of pounds per square inch of pressure (you can walk on the stuff within a minute of spraying it).  I did quite a bit of research into this option, and it is equal to the pre-insulated PEX in water resistance, EXCEEDS the pre-insulated PEX in thermal conductivity performance (less heat loss), and saved me approximately $2000 in this trench run.  

The contractor I used had plenty of experience in this process (of insulating lines underground) both in remote wood furnace applications, but also for insulating potable water lines from distant wellheads.  He told me that the longest stove run he ever did was over 800'.  I know I sure wouldn't want to walk that far in the snow to load my stove!

My trench is about 36" deep, below the frost line for 90% of the winter exposure we get here.  Code is 42", but that is 8" deeper than the actual max frost depth for foundation footers.

Hello Jim and Kenny,

Wow, I found the link right away.  Typed "sprayed polyurethane foam below grade canada" into Google, and the second link had the article free (first link to article had you paying $31.50 for a copy!)....

http://www.cufca.ca/research/Basement%20Insulation%20Report%20-IR820-English.pdf

 :-)

 Hank

tat, my garn barn was insulated with spray foam, due to the roof framing i would not have been able to vent conventionally, installed a roof vent controlled by a humidistat , helps with the stored wood discharging of moisture as it warms up.

jim, as the sticker shock influenced my desire to resource the trench issue, i have not been disappointed with the foam approach i used, first lining trench with a continuous piece of sheet plastic one end to the other,constructed a 3 sided blueboard chase, installed sch. 40 conduits for supply and return sleeves,sprayed foam under around and on top of conduit to top of chase, installed blueboard top and folded sheet plastic over top. in the end it was a more work than the premade option, but after 2 winters shows signs of heatloss.

Jim,Hank & others,

      Don't get me wrong, I am a big fan of closed cell foam particularly on building envelopes. I think it is the best way to seal and insulate a building. However, and this is just me being cautious, I know that different applications can deliver different results. What I would like to see is a test on buried insulated pex pipe in a horizontal ditch in a freeze thaw climate with fluctuating water temperatures over say a three or four year study. Ideally the test should include temperature drop over the length of pipe in relation to flow rate. And if any of you guys are willing to do that maybe you wouldn't mind running a parralel test using a pre-insulted duo pipe system so we could all finally know for sure. It's really not a big deal if you have a lot of time and money. LOL. When you get right down to it, water is the "K" factor for underground heating lines (That's K for Killer) and that is where my concern & questions lie. I KNOW it is not a problem with a continiously cased system. It HAS been tested and proven. I definatly will use closed cell foam on the entire envelope of my next home but my pipe will be in a water proof casing unless I get proof. Incidentely the foam is combustable so you (and I'm guessing you know this) should cover it with dry wall. Please know that this is just my humble opinion and not a criticism of your choices.

 I've been using sprayed foam on all of the installs I get involved with and recommending it on every job. A person needs to do his research to make sure the insulating contractor is up to snuff on what he is applying but I have found nothing better than 3-4" of two part closed cell urethane foam for insulation. The company I use has been doing underground pipe and tube insulating for many years and they have not documented a single failure. The R and K value of the product is outstanding. W normally bury our tube no more than 30" or so and I have yet to see any sign of heat leakage at all on any of our installations. The proof is in the pudding so they say and actaul field measurements that I have done indicate very little heat loss. Case and point. We installed a 600 foot round trip loop of 2" pex on a job last year. Circulating the fluid with no attached load, only the ground loss, showed a temp drop that was indeed hard to even measure with a digital thermometer. An average reading was  .4* )that's 4/10's of a degree) The flow rate in the tube is roughly 23GPM. That particular job goes under a drive that has heavy truck traffic on it daily and at no time has it ever shown a trace of heat loss or thawing while the ground aruond it was frozen. I'm a believer.

Steve,

    That's very compelling testimony and just the kind of thing I need to hear before I will become a true believer. Don't take this personal Steve but I would like to hear from some others what thier experience is with ditch foaming. Will any closed closed cell foam work or do you need to specify a particular process or brand. 

 In a nutshell, it has to be closed cell urethane not the bio based type foams so no, all foams are not created equal. :)  The product my guys use is a two part that is heated and sprayed through a mixing nozzle. It is hard enough to walk on in about 5 minutes.  It should be a minimum of 1# density (per cubic foot) to stand up to compressive loads such as under a drive. There are a few different manufacturers of the stuff but I can't recall the name of the product my guys use right now.I'll pass it along if I think of it or else I'll ask them the next time I'm on a jobsite with them.

Hello Happy Garn 1500 Owner,

Your install of the foam looks nice in this photo.

We are planning a barn-conversion-to-home and will be doing with closed cell polyurethane foam what is done on geodesic dome homes, and what was done with the Superdome in New Orleans... Our barn is 36' x 104'. It has a milking parlor on first floor, and the hay mow above is 25' from floor to peak of the curved/arched roof. The 53 arches are made of beautiful laminated fir which are 1" x 6.5". We will keep the arched beams exposed. After we complete the roofing, and put in all outside windows (including a bunch of Velux Skylights) and doors we will put plastic on everything we do not want sprayed - then  we will have a well-selected contractor apply 3" of Sprayed Polyurethane Foam (SPF) on the outside of the structure - from peak to ~2 feet below grade. Next, a layer of appropriate primer, and finally an elastomeric paint.  This will obviate the need for Tyvek, will be our insulation, will be our roofing, will be our siding, will be our water barrier, will be our vapor barrier, and one added benefit, it is self-flashing.

((((Regarding the self-flashing aspect - it MAY be possible that we will not need to 'flash' any of the windows or doors.  This may be totally FOOLISH, so I need to check it out fully before I decide to do this. If it is not only OK but acceptable, has been done, and is advised, then I will be dispensing with the initial labor-intensive job of 'flashing' all our openings. The simple point is - only if I can find solid evidence that the self-flashing aspect of the SPF is sufficient and will work well over time will I do it this way ---- anyone help me out here???)))

((((Another thing which will hopefully be addressed by readers - I know the building will be outrageously 'tight', and I will need to do something for air-exchange. Particularly since we plan to do in-floor radiant heat.  Anyone have knowledge or able to direct me to a web site or published book where I can find out how much and how-to-do air exchange for such a tight structure?!))))

I realize this building will look different, odd, or even wierd to some, but I believe if I choose the correct SPF contractor it can and will look 'good'.

NOTE: In my extensive research on using SPF as the outermost part of the building envelope I have seen where they measure the actuall R-value of the BUILDING after it is all up and running. It is a simple experiment and calculation - monitor temp inside the building and outside the building over some predetermined length of time (say 24 hours), and determine how many btus of energy (btu per min X total min furnace burned per the 24 hours) were required during that time ( 24 hours) to maintain the measured inside/outside temperature differential. Plug numbers into an equation and out pops "R-value" of the structure.

Interestingly, R-values for the entire structure are determined to be between 60 and 80! The reasons are....

(a) since the building is surrounded by a closed cell foam, the entire building stays at  the inside temp set by the thermostat, and the entire building thus functions as a huge heat sink.  Pretty aswsome....and

(b) the self-flashing nature of the SPF means that there are NO holes in the skin you put on the building, NO air leaks. ALL the holes you put in the roof and siding are sprayed with foam AFTER you are done with the siding, vents, windows, doors installation.  Think about it, after you put on yur excellent Tyvek product which is supposed to function as your vapor barrier you then put on your siding and your trim - after you put up your vapor barrier you punch several thousand holes in it! - where is the 'wisdom' here?!   (Wow, I sure rambles on, didn't I?

As with the information demonstating the integrity and functionaligy of the SPF applied to a building above and below grade and the published article from Canada...(link repeated here), I will see if I can find the link to any of the reports which describe this (admittedly unbelieveable at first blush) astronomical R-value.

Link to Canadian Article about functionality and integrity of SPF applied directly to concrete above and below grade to outside of a building...

http://www.cufca.ca/research/Basement%20Insulation%20Report%20-IR820-English.pdf

AHHHHH!!!

I did find one link regarding insulating by spraying on the outside of a concrete building...., Here is an exceprt from the article, and then link to the article. (I will continue to look for additional information, and perhsps edit this post when/if I find it....."

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Thermal Diffusivity and Heat Sinks

It should be noted that when the urethane is used on the exterior of a heat sink, such as concrete, the actual effective R-value is approximately doubled. This is why with the Monolithic Dome, we are able to calculate effective R-values in excess of 60. A heat sink is any substance capable of storing large amounts of heat. Most commonly we think of concrete, brick, water, adobe and earth as heat sink materials used in building. The property of a heat sink to act as an insulation is called thermal diffusivity.

The simple explanation for the way it works is: As the temperature of the atmosphere cycles from cold to hot to cold to hot the heat sink absorbs or gives up heat. But because the heat sink can absorb so much heat it never catches up with the full range of the cycle. Therefore, the temperature of the heat sink tends to average. Large heat sinks will average over many days, weeks or even months.

An example is the adobe hacienda with its 2 to 6 foot thick walls. By the time the adobe walls begin to absorb the daytime heat it is night time and the same heat then escapes into the cooler night. Therefore the temperature would average. Because the mass of the adobe is so large the temperature averages over periods of months. Adobe acts as an insulation even though adobe has a minimal “R” value.

You can see from the graph that urethane thicknesses beyond four or five inches is practically immaterial. We use three inches for most of our construction. Two inches will do a very superior job. We have insulated many metal buildings with one inch of urethane and the drop in heat loss is absolutely dramatic. Obviously the first quarter inch takes care of the wind blowing through the cracks. (It usually takes an inch to be sure the cracks are all filled.) The balance of the inch adds the thermal protection.

http://www.bestsprayfoam.com/R_Value_myth.htm

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Sincerely,

Hankovitch in SW Wisconsin

 For anyone that has been following my GARN blog, I have updated it with my latest entry.  It is all text, explaining how we decided on the GARN, installation issues, operating experience, and things we would do differently.  www.pennbrookfarm.com/garn/garn9.html is the latest page.  Links to the previous pages are on the bottom.