Cement overpour for radiant over existing cement floor.

[MrEd]

In the coming months I'd like to add the first radiant zone to my FHW baseboard system. I have a 16x20 foot office in the basement that is always cold. It has a cement floor. I am wondering if it is possible to put a overpour of cement over the existing slab and embed radiant loops at the same time? Would I need to do any special prep work to the existing cement floor to get a good connection between the two? Would you still need to use mesh/rebar since it is going over an existing pour? How thick should an overpour be?

Thanks.

 

[Couderay80]

Absolutely yes you can. Vapor barrier first followed by pink or blue board thickness is up to you I like 1" in this case. Next wire mesh and nail it down with concrete nails allowing a little wiggle room. Next tie your tubing to the wire mesh and cover with concrete. Don't forget perimeter insulation. Cap the tubing off and pump up to at least 50 psi while pouring concrete. Big draw backs in doing this is, can you afford the extra height with the insulation and concrete in your basement. I done it in mine and it works like a charm. I used bubble foil bubble (cringing) and this was designed by an engineer for my house. Yes I poured a floor over a floor in a new construction house. Been for years and working like a charm.

 

[88rxn/a]

interesting!
to bad i already have to almost duck to get through my basement!
how much height did it add to yours?

 

[Couderay80]

The floor that contains the tubing is 3 inches thick as the supply and return are 1" copper.

 

[MrEd]

Is that 3" of concrete? or 2" concrete plus the 1" insulation?

 

[Couderay80]

I went with 3" inches of concrete over my piping and insulation. The pics above.

 

[DenaliChuck]

I think you could do a 2" slab over 1" foam with 1/2" pex for a total height loss of 3".

 

[whippingwater]

What about using something like this: http://www.infloor.com/infloorboard2.html

 

[Willman]

Check out a product called Bekotec by Schluter. No rebar minimum height build up, designed for this application. Used extensively in Europe. Coming on strong over here too. I went with 2'' blue board with the Bekotec on top. Will pack a mud screed on top.

Will

 

[BrownianHeatingTech]

You can also put down vapor barrier, insulation, and then WarmBoard over the top of that. Won't eat as much headroom as concrete.

Joe