I am renovating a century-old farmhouse that was given a basement in the early 40s. They did a great job pouring the concrete foundation and it is dry and solid to this day. However, it only has about 7 feet of headroom in its unfinished state. I would like insulate above the slab, install hydronic tubing and finish the floor, without gobbling up any more clearance than necessary. I was thinking of putting down 1-2″ of EPS, then PEX, then finish. Not sure what my options would be…any suggestions?
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Check out Roth Panels... designed to go over existing slabs.
There was a good article in FH by Andy Engel titled, "The stay dry, No-Mold Finished Basement." Basically, he puts a layer of EPS on the inside walls and floor to isolate the interior wood from the concrete. Then he laps 2 layers of 1/2" plywood on the floor (screwing them into the concrete), and builds a stud wall on top of that. In the article, he added a finished floor of cork over the plywood.
The only difference in my project is that I need to incorporate hydronic tubing into the floor for a heat system, and I need to do so without adding alot of cost or losing alot of headroom (we only have 7 foot ceilings). Also, I fear that 1" of plywood is going to be a detriment to upward heat flow from the hydronic tubing. Therefore, I came up with an idea of routering a serpentine into the EPS to accept the PEX tubing, then installing a layer of cement board (screwed through the foam into the slab) over the top, instead of the plywood method. I can then apply a finish floor of tile or cork over the cement board. This would be relatively inexpensive and I could do it all myself as a DIY'er.
Any suggestions on whether this would work, or if there is a better way?
Thanks!Shawn
As far as I know, you are planning something that should not be done. Routing path for pex defeats any insulation purpose. You want the heat to come up, not heat the whole slab and ground underneath. When you don't have the headroom it is just the way it is. You also want the heat to be distributed evenly, so the need for aluminum plates. Otherwise, you'd walking over, or resting your feet on, cold and hot spots. Also 1 inch insulation is not enough. That may give the floor some feel of warmth, but not make the heating efficient, you'd still be heating the slab and ground.
I would forget the radiant heat. I would consider forced air heat that gets the heat from hot water. There is no special material or trick that will get you good radiant heat and save you the headroom. Hope this helps.
I hear what you're saying, but I don't think you understood what I planned to do. I was going to use 2" foamboard on the floor, and router a channel (5/8" deep?) to accept the PEX tubing. Then the cement board on top of that. This way there would still be 1.5" of insulation under the tubing, as a thermal break.
Your point about cold spots is a good one...maybe I could use the aluminum plates in this application to direct the heat upward and outward?Shawn
You're trying to invent a new way to do something... it doesn't sound promising at least to me. I would stick with industry standard methods. Why go to all that trouble just to find out you have a big problem?
the method you describe, i wouldn't do.
good ceramic tile installs are about elimating movement in the substrate.
a routed piece of even high density foam with cement board screwed to it is going to flex because your slab is uneven. as a result your tile joints will crack.
if i were you with a low basement ceiling and i was going to do this myself, i would rip out the slab, dig for space for as many inches of EPS as I could get and pour the PEX tubing into the slab. this would allow you to put in polyethylene and a footing drain. for not a tremendous cost. and no loss of ceiling height.
or you could put in PT sleepers over your slab with foam in between and plywood on top.
carpenter in transition
What about an electric version instead, like Warmly Yours?
http://www.warmlyyours.com/
You'll save a bit of room that would have been carried by the PEX.
Yes, that would help. But, we are trying to tie this house into a central hydronic heating system that serves several buildings. So I need to figure out a way to get the tubing into the floor.Shawn
What if you go ahead and lay the 2" of EPS and then the one inch of plywood? Then route the grooves for the PEX AL-PEX in the plywood? Cement board alone on top of the EPS wouldn't be stiff enough I believe. My suggested method would be be as follows - 2" or more EPS, then the two layers of 1/2" plywood, then route the grooves into the plywood and form aluminum plates to silicone the PEX AL-PEX into, then lay 1/4 inch cement board on top of all that with a modified thinset. Then tile. You would be giving up approximately three or four inches of headroom. Perhaps see if that is acceptable by placing two 2x4's flat on top of each other (for a combined total of 3") and stand on them in the basement to see if you can live with that loss of headroom? It is labor intensive but the pleasure of the reward may well be worth it.
Handyman, painter, wood floor refinisher, property maintenance in Tulsa, OK
Shawn, what you are trying to do is make your own Roth panel. The problem with your design is you dont have anything in direct contact with the tubing to transfer the heat. Roth panels are insulation with grooves cut out and aluminum covering the top and in the grooves. Snap the tube in and your set. Probably around $4 sq/ft. tubing included. Search the internet and put your own package together and maybe save some money, talk to you local plumbing supply house and see what they way or contact NRTRob and he'll do you right.
If you are loking for a source of heat from your floor I wouldnt use the electric wires. They arent made to use a the sole heat source, keeps the floors warm but thats about it.
Heres one we just finished.
Looks like a nice system. What do you install over the panels, before the finish flooring can be installed?Shawn
on this one the finished floor wa 3/8" laminate hardwood (floating). We layed down the 1/8"foam and then installed the floor.