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# Heat transfer through concrete suspended floors

Member Posts: 1
<span style="font-size:12pt"><strong>Heat transfer through concrete suspended floors </strong></span> <span style="font-size:12pt">I am currently planning a 3 storey house, with suspended concrete floors.  The basement is a concrete slab on ground, and the 2 Floors are positioned directly above one another and will be 75mm concrete flat slabs with a 75mm topping slab (so total thickness 150mm) </span>

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<span style="font-size:12pt"><em>My question is if I put u/floor heating in the basement slab will the heat rise through the upper 2 floorslabs, or will each slab need to be heated independently ?  I know heat is lost from ground slabs to ground (hence insulation under slab) so I assume there is thermal transfer through slab, however I am guessing the issue is more about are the room temps below suspended slabs enough to allow heat transfer through each floor ?</em></span>

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<span style="font-size:12pt">John</span>

• Member Posts: 514
I am having

trouble picturing the situation

How much space will be between the floor materials?

Are these three floors of a home with like 8 ft between? If so they all will need to be heated.
• Member Posts: 669
heat rise

Yes heat will rise through each layer of concrete BUT you will need to heat each level.

The basement has almost no heat loss compared to the other floors - so the heat won't run in the basement enough to heat the upper levels. You need to install a heat source on each level. With a seperate trermostat on each level for even heat under different outside conditions.
• Member Posts: 22,916
The heat will transfer

through the concrete slabs in exactly the same way as it transfers through any other material -- by conduction.  And the rate will be proportional to the temperature difference between the space below and the space above, and inversely proportional to the thermal resistance of the floor.

The rate can be figured quite conventionally.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
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