grout type change for new vertical loop

Discussion in 'Quotes and Proposals' started by dawei, Jan 21, 2011.

  1. dawei

    dawei New Member

    My contract calls for the installation of "bit night geo-grout" in the well holes for my vertical, closed loop system. Today, the contractor indicated that the well driller he works with may not be able to get his grout rig up to my house. As an alternative, he mentioned the use of granite pea gravel as the grout, since he knows he will be able to get a dump truck to my house carrying pea gravel.

    I'm wondering how granite pea gravel will perform as a substitute for geo-grout? Will the installation be any less efficient using gravel? Is there anything else I should know about this possible switch?
  2. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    most grout plants will fit into the bed of a 1 ton pick-up, Some are on dual axle trailers. Mine is on tracks and self propelled. If he can get a dump truck and drill rig on site.........
    Grouting with bentonite grout from the bottom of the bore hole to the top is the industry accepted minimum, using sand to enhance the grouts performance is usually spec for commercial jobs.
    Search grout here for all your answers.
  3. dawei

    dawei New Member

    Many sincere thanks for sharing your expertise, Eric! I have also read some of the other posts when searching under grout, as you suggested. I will continue to read in order to keep on top of my job.

  4. Sounds like your contractor and the contractor's driller could benefit from additional information as well.

    Even considering pea gravel is disconcerting at best. It indicates a lack of knowledge and expertise both of which can be easily corrected.

    Perhaps you can point your contractor(s) to this forum.
  5. Looby

    Looby Member Forum Leader

    Aside from thermal concerns, pea gravel will not protect
    your aquifer(s) from contamination by surface water -- or
    cross-contamination between aquifers.

    It would be a major code violation in my neck o' the woods.
  6. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    the real name for this is Bentonite Grout

    You can read all about it here.
  7. dawei

    dawei New Member

    Many thanks for your posts, Phil, Looby and Dewayne. The aquifer primer you provided, Looby, certainly adds weight to my negative feelings about using gravel for grout in light of Eric's post.

    Dewayne, I had already done some reading about Bentonite after realizing that is the name my contractor doesn't know. Interesting as well as very useful clay from Wyoming and Montana!

    Here's another question. The contractor is talking about having to bring the two loop lines above ground for about eight feet or so in order to get them from where the three or four vertical bores will be tied together--from that point into the house due to the location of a stream that's part of a water feature which is in the way. He doesn't seem to like this idea and has said he will have to insulate the exposed lines very well.

    The more I have thought about it, the more I agree with his dislike of this idea. My understanding is that the lines from the vertical bore holes will be tied together about 4-5 feet below the surface and that from there they should remain at that depth into the house. It seems to me that having to bring the lines above ground defeats the primary thermal reasoning for drilling the deep bores in the first place.
    I don't think the lines can be adequately insulated to avoid thermal loss, not to mention the appearance of insulation near the entrance to the house. I'm exploring an alternative to the proposed exposed loop lines.
    What are your ideas about this?
  8. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    I am sorry this is going where it is headed. I smell really bad cheese from a busines and education standpoint.
    The truth of the matter is that all vertical loopers are drillers, but not all drillers are loopers. The grout issue was the first flagg. while it may be okay to pea gravel grout a water well, it does not protect multiple aquifers or promote uniform conductivity for a loop. location location location. While running some distribution lines above ground for a short distance is not the worst thing in the world, it is not good either. Why was this not identified early on in the design bid proccess so all parties could aggree on a course of action?
    There is nothing I hate worse than a design build while the project is in motion. Change orders allways hurt someones wallet be it the customer or contractor. Lack of competant knowledge or education about the task at hand is also a problem.
    I would suggest either tunneling under or horizantal boring under problem area rather than daylight pipes, insulation or not..
    Sorry for the rant, but crap like this does nothing to help the industry only hurts.
  9. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    I suggest you look on this site for geo drillers in your area or check the igshpa (international ground source heat pump assoc.) for certified geo drillers in your area.
    We are going about this backwards, but I would tell the contractor that you have lost faith in his design and find out if he can resolve your concerns.
    The code and contamination questions may be real concerns, but there are actually places where there are no such codes and if you have a wet well, heat transfer would work fine.
    So let's meet with the guy you hired before moving forward. Worst case if you have to cut and run and it costs you a couple bucks, it will still be cheaper than repairing a poorly installed system.
    Good Luck,
  10. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I try not to get too hung up on spelling and grammar, but "bit night" for "Bentonite" suggests a truckload of cluelessness along with the gravel...not a good sign.
  11. dawei

    dawei New Member

    Again, many thanks for your most valuable thoughts, Eric and Joe! Your professional, experience-based input is even more valuable than you realize in light of the following.

    We live in an area where there are no geo-thermal professionals, either drillers or loopers. I did go through the list of professionals as listed on geoexchange but found nobody here in Western NC near Asheville. I was only able to find the contractor I signed with by going through a regional equipment supply organization. They could direct me to just one looper who is willing to travel to a job as distant as my location. This looper is based more than a two hour drive (one way) from my home. So, my wife and I did not have the luxury of accepting multiple bids for the job. That is why your input and advice is extra important to us.

    The thought occurs to me that my location is probably not unique across the country in being a fair distance from qualified loopers. I'm sure we're not alone, and this might be a topic that the industry would want to address at some time.

    A friend of ours who is a general construction pro is now looking for a local guy who can do the horizontal bore necessary to avoid bringing the loop feed lines above ground.

    We have decided that we will not go for either gravel grout or for above-the-ground lines, and I will be communicating this to the contractor.

    By the way, can you tell me if both feedlines are or can be run together from their tie-together point into the house, or must they be kept physically apart? I ask in regard to the horizontal bore hole requirements. Can it be one hole, or must it be two? My understanding is that each of the loop feed lines is 2-in dia. So, does that require a horizontal bore of 6-in.,or perhaps 8, assuming both lines can be run together?

    Again, your advice is most appreciated.

  12. Bergy

    Bergy Member Industry Professional Forum Leader

    2" supply and return pipes?? How many loops are going to be installed?
    Our retrofit jobs use horizontal bores with a horizontal bore under the house into the mechanical room for a header shot using 1 1/2" HDPE.

    Perhaps it's time to slow down a bit and make sure the money you are spending is spent well.

  13. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    Agree with all that has been said. My comment about location was in relation to your jobsite. The grout plant issue, water feature obstruction, and possible solutions would have been better dealt with on the table up front, not now. It is one thing to say drill here, but how are you going to connect the house to the bores?
    all is never lost, with some carefull planning moving forward, with all contractors involved this can and will work for you in the end.
  14. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    Just to be clear, the supply and return lines can be run in the same horizontal bore.

    It is doubtful that you need 2" lines unless you have more than 10 or so bore holes.
    Last edited: Jan 23, 2011
  15. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Bit Night....
    It do harken lots of Jeff Foxworthian comments
    Last edited: Jan 23, 2011
  16. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    .....European used in a sentance......
    If European on the seat ya gotta lift it before you make water Elmer.....
    sry couldn't help myself
  17. dawei

    dawei New Member

    Eric, the contract does call for the installation of geo-grout, no matter how poorly it was spelled. The type of grout was not an issue until the contractor told me on Friday about the well driller's concern about getting his rig to the house. Funny, but the well driller did not mention this when he visited the site not long ago for a look-see. I call it a definite curve ball.

    As for the above-ground lines, the contractor possibly couldn't see any alternative, with his coming from some distance away and not knowing anyone in my area. Of coarse, that's a guess, but he did not offer any alternative ideas when he first looked at the site or during a return visit later.

    Thanks for spelling it out for me, Dewayne. I needed to know that one horizontal bore will do it for the supply and return lines. As for the size of the lines, I see that I was mistaken. The contract describes 1" loop pipe in bores. It calls for approximately 1,200 feet of geo-bore. That will either be done in three or four vertical bores.

    I have refrained from bringing up the grout name question to the contractor, even though I don't understand why he doesn't know it.

  18. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Does anyone else feel like they are watching two trains about to collide? All our yelling to STOP! can't be heard by the operators........?
    David it may be cheaper to interupt this install than proceed.
  19. dawei

    dawei New Member

    A question about the supply and return lines themselves: I understand that they can be run together, but I don't understand how that can be done without thermal losses between them? I'm thinking that one line carries water of one temp., while the other carries water of a different temp. Do the two lines require any type of insulation between them? If not, what prevents thermal loss or transfer between the the supply and return lines?

    Further exploration of the plan to bore horizontally under the water feature stream that's close to the house has run into the problem of waterproofing the exterior foundation wall that would be penetrated by the bore. There simply is no access at that location and depth for waterproofing. So, that takes it back to the above-ground routing for the supply and return lines that can penetrate the foundation wall above ground and therefore provide access for waterproofing at that location.

    What type of material would you recommend for best insulating the two lines?

    Does it make sense that the insulation should begin down in the trench where the two lines first begin their upward rise toward the surface for maximum thermal benefit?

  20. dawei

    dawei New Member

    A P.S. about my insulation question. Winter temps. in my location can approach or reach zero during short periods, and the windchill at those times can be in the -10 to -20 range.

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