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gypcrete alternatives?

Ric Member Posts: 2
I'm considering a hot water heating system with the tubes running on top of the floor, between sleepers. Normally, it seems this work is completed with a light weight concrete overpour, which where I live is very expensive. I've read articles about people in the US simply covering the pipes with sand, then fastening their wood floors or adding a subfloor as an alternative to a concrete based overpour system.

Has anyone heard of this? Is it generally accepted by building codes? Is it as efficient as concrete? If no, what alternatives can be used that are not as expensive?

Thanks for any advice.


  • Ted_5
    Ted_5 Member Posts: 272
    Sand is not good

    I tried it and I was not happy with the performance. The water temps where alot hotter then gyp. I have had a 1 1/2" concrete pour over the sub-floor and that works good. It is about half the cost of gyp and performs better.

  • hr
    hr Member Posts: 6,106
    Stay away from sand

    it's kind of an insulator! It also provides ideal nesting for ants and other insects.

    The beauty of gyp is the easy of installation and leveling AND it doesn't crack and move like thin concrete pours!

    If small cracks aren't an issue for your floor coverings, and your joist are up to the tasjk of supporting the weight without movement than a beefed up 1-1/2" pour may work.

    Check out the Yourker mix for this. Thanks Harvey!

    517 lbs type 1 portland

    1639 lbs concrete sand

    1485 lbs 1A crushed stone 1/4" max diameter (pea gravel)

    4.14 oz air entrainment agent

    15.5 oz Hycol or equal (water reducing agent)

    1.5 lbs fibermesh

    51.7 oz superplasticizer (WRDA-19)

    20 gallons of H2O

    Your local yard may have substitues for these ingrediants. Send them this "Youkers Recipe" they will get the idea.

    Ideally you want 1-1/2 times the aggreate size over the tube. Stick with 1/2 or 3/8" tube to assure this.

    hot rod

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  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    "kind of an insulator"

    Would that imply that it can be made into a semi-conductor?

    Sorry--couldn't resist.

    If weight is a problem you might want to consider Warmboard or similar that puts a conducting surface on top. Not sure about pricing/availability in your market though.
  • Ric
    Ric Member Posts: 2

    I'm definitely getting the impression that people are not keen on sand.

    Where I live it is difficult to get people to do over pours. That's why I'm wondering about alternatives. In fact in my geographic location, there's only one gypcrete installer (who can set his own price... and does). Is $4,500 too much to cover 1,800 square feet? Seems so to me.

    Thanks for the help so far!
  • hr
    hr Member Posts: 6,106
    Should be able

    to get that Youker mix from a local batch plant. A small pumper or grout pump could place it if it needs to go upstairs.

    The gyp guys need to cover expenses, it's a large equipment and personal operation to travel for a small pour. Hauling the rig and trucking good quality sand to the job, along with a crew takes time and $$$! There really is no substitue for gyp if that's what you have your heart set on.

    Thin concrete pours are just another option as long as you understand the differences and limitations.

    Plenty of dry, on top, or below the subfloor systems out on the market. They can come close, but never match a thin slab for nice uniform heat spread and some thermal mass, along with the sound dampening and fire stop protection Gyp can offer.

    Or try Troy Morgan Gypster Supreme. He might travel that far, for the right carrot :)

    Weed through the options and find the best match for your application.

    hot rod

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  • Troy_3
    Troy_3 Member Posts: 479
    Gypsum concrete

    That is actually a very reasonable price I think. We qoute $3/sq.ft. and have for years. Where are you located? Thanx Hot rod. I agree that you can't beat the benefits of a thermal mass. Over a wood frame structure I feel so strongly that gypsum is the best option that I invested over 100k to do it my self. I wouldn't recommend that. I have tried most options and still use many dry systems when the application calls for it. If it is feasable I recommend gypsum concrete. Having said that I am currently installing 10,000 linear feet of thermofin C. Sometimes Gyp just won't fit. I get a premium for thermofin C and tube under floor. Back to gyp- Make sure the applicator is familiar with radiant jobs. Custom homes are a lot different than Motels. E-mail me if you have questions.
  • kevin coppinger_4
    kevin coppinger_4 Member Posts: 2,124
    another thought.....

    and a good one, would be to abondon the wet mix stuff and use Wirsbo Quick track or the stadler version. Heatway and the others have their versions...I like the system easier install, low water temps, quick responce....a bit moer in $but a lot less aggrivation...kpc
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