# Insulate over slab / under wood floor



## mjoe (Oct 7, 2010)

Hello,


My wife and I are in the middle of a house renovation and we have come to the point where we are going to be installing the floors.


The house is a one story brick ranch in northern Ohio. The majority of the house sits over a basement, but there is an attached garage on a slab and a family room that is adjacent to the garage that sits on a raised slab.


We will be laying a floating bamboo floor over the entire first floor (minus bedrooms and bathrooms)


So, for the family room, the floor will be installed over the raised slab (which currently has tar glued down vinyl "tiles" circa 1970). What we would like to do is insulate over the slab and under the floating floor if this is possible.


I have seen where people glue down polystyrene foam board under floors, would this be something I could install over the concrete and under the wood flooring?


If not, are there other possibilities out there?


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## Gary in WA (Mar 11, 2009)

Last few pages; http://www.buildingscience.com/documents/insights/bsi-003-concrete-floor-problems?full_view=1

If using f.g. under the wood, don't let any air get to it; http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces/

Gary


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## mjoe (Oct 7, 2010)

So throw down ditra or an epoxy coating first? 

Does that mean remove the old tiles that are tarred down? What about the tar? Is there a way to remove 40 year old tar from concrete?

Is this just if I want to use polystyrene or something I need to do to out a wood floor over my slab even without insulation?

What would be the problem with a normal vapor barrier?


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## Gary in WA (Mar 11, 2009)

The tiles and adhesive will act as a vapor barrier being petroleum based. If you want warmth, add the rigid foam boards. 

"Is this just if I want to use polystyrene or something *I need to do to out a wood floor* over my slab even without insulation?" --- having trouble understanding this question, could you rephrase it please?

Gary


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