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In slab pipe insulation

I tend to be my own worst enemy by over thinking things. I am working with a very contemporary architect on 2 projects. These homes are both slab on grade with very open floor plans and limited interior walls. I am going to have to install my supply/return lines to remote manifold in the slab. I have done this in the past, but now I am wondering if I should insulate the S/R mains for a few reasons. First they will be running through other heating zones and rejecting heat along the way. Maybe creating warm spots. Next, if the S/R lines are loosing heating along the way to their zone the water temp will not be hot enough to satisfy the zone. One problem with this is I am working with a 4-5" slab with wire mesh and tubing in it and then these S/R lines will be installed over top of this assembly....not leaving very much space for concrete over top.

About 5 years I started insulating my S/R lines to my remote zone manifolds for performance and expansion sound. I like this system, but what about the slab.

Thanks for your input Jeffrey
Jeffrey Campbell

Comments

  • Jamie HallJamie Hall Posts: 8,535Member
    Argh. In my humble opinion, insulation is sort of optional. What is NOT optional in my opinion is that a)you should use flexible material -- e.g. PEX; b)there should be no joints of any kind in that flexible material; c)where it enters and leaves the slab there should be enough space to pull new pipe in when you need it and d)it should be in conduit.

    Don't ask why I have strong opinions on this... it's not a pretty story.
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • Ditto what Jamie said although I would definitely insulate the lines to keep the temperature from dropping. You also don't want to heat a zone that may be turned off.
    Often wrong, never in doubt.
  • Simply RadSimply Rad Posts: 144Member
    Definitely no joints or copper. I used PAP tubing for my distribution system. I am curious though what type of insulation is appropriate and rated for in slab installation? Any ideas
    Jeffrey Campbell
  • ratioratio Posts: 1,566Member
    Any possibility of getting it below the slab? Scrape out a little gravel & throw it in there? Much better than going in the slab itself.
  • GordyGordy Posts: 8,029Member
    Insulate, and go under. Maybe using insulated supply return like for outdoor wood boilers.
  • Stephen MinnichStephen Minnich Posts: 2,051Member
    Under and then back up with this. Watts, Uponor, and other manufacturers.
    Steve Minnich
  • MikeGMikeG Posts: 150Member
    I there any way to plan for and route your supply and return to the manifolds to provide the heat for the area they run through., without redundant heating. Also have to factor in the required supply temp needed at the manifold if this is even feasible.
  • Simply RadSimply Rad Posts: 144Member
    I have to travel through the Great room in order to get to the master suite. I just am wondering if it is really better to run insulated lines under the slab assembly in unconditioned space? I am thinking that if they are run in the slab then any heat loss is heat gain. Something to ponder. Mike G i agree with you about looking at supply temps for the zone they are running to. The one thing I am thinking about is if the great room slab, which is the highest heatloss area is operating under continuous circulation then the heatloss on the S/R lines running to the master suite zone would be minimal...just my 2 cents
    Jeffrey Campbell
  • GordyGordy Posts: 8,029Member
    Underneath thought was just to avoid minimal coverage if you go over everything. Sounds a bit more costly,and laborious, but do a thickened trench for the S/R sets. Insulate the bottom of the trench, and not isolate them from the slab. This of course is if you want to keep lost btus to the slab. However if you want to keep the temps up in the line set then use what @Stephen Minnich posted.
  • Jamie HallJamie Hall Posts: 8,535Member
    Just make sure, whatever you do, that you can fix it when it leaks...
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • Solid_Fuel_ManSolid_Fuel_Man Posts: 1,057Member
    Can you run below the mesh/rebar, but above the foam insulation? That's where I run conduit for wireing and domestic water chases.
    Master electrician specialising in boiler and burner controls, multiple fuel systems, radiant system controls, building controls, and universal refrigeration tech.
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