2x10 over a radiant slab

John Felciano

Having a 10" dead air spece over the floor will severly diminsh the output of the cement slab.If there is enough left to provide enough heat to satisfy the room will depend on the heatloss of that room but I would be very doubtfull.

Why not just add a new radiant floor to the top of the new finished floor?

Lynne

2x10 over radiant slab

Can radiant tubing in a slab heat a room on top of it that is built up with 2x10's?

Unknown

it depends

John, you know, it ALWAYS depends

if the load is low, it might be fine. You have direct radiant to the floor underside, plus that sounds like a convective situation to me moreso than a dead air space. heated bottom, cold top.

certainly not ideal, but I would think you get some heat out of it; question is, will it be enough?

low load, low R floor coverings, might be ok. I would wonder why 2x10's are being used though, that's a pretty crazy build-up height.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Unknown

it depends

John, you know, it ALWAYS depends

if the load is low, it might be fine. You have direct radiant to the floor underside, plus that sounds like a convective situation to me moreso than a dead air space. heated bottom, cold top.

certainly not ideal, but I would think you'd get some heat out of it; question is, will it be enough?

low load, low R floor coverings, might be ok. I would wonder why 2x10's are being used though, that's a pretty crazy build-up height.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

John Felciano

I agree

It does depend on the load.

We've run into it before where people have built up decks for jacuzzi tubs on top of the radiant floor and the temperature on top of the raised deck is a fraction of what the floor is.

But who knows with a real light load it's possible,But how would you calculate what the outcome will be?

Mike T., Swampeast MO

Are you perhaps adding a bath with the drain piping going in that big gap?

If space is small, should be a good place for electric radiant right below the new finish floor. Should reduce the load on the electric portion a bit so make certain that you control it thermostatically.

Weezbo

may be ....

here is some things to look into , is it within the building with no exterior walls ? is the area large in comparison to the overall dimension o f the building ? does the room with the 2X10 floor have windows ? sliding glass doors ? is the room like an indoor atrium ? raised floor in low ceiling height loft ? lots of variables that might decrease the actual amount of btus needed....then there is also a question about air currents in above around beneath the floor like well, you get the idea....

Lynne

it has exterior walls

it has big windows, it's the new kitchen open to family room which has radiant in the slab also, but the floor is right over that slab, kitchen was built up to match the existing structure. The thought now is to suspend more tubing between the 2x10's but there is no more insulation going in.

Unknown

I would pretend the 2x10 space is a "room", calculate its "loss" to the area above at the expected delta T (slab surface to room temp), and see how that matches the real room's loss. I make no claim that this is a scientifically defensible way to do it, but that's what I would do.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

STEVE N

WHY NOT

WHY NOT USE PIPE TRACKING ABOVE THE 2 X 10S FOR A SUB FLOOR? I'M NOT SURE OF YOUR CONSTRUCTION PLAN BUT PIPE TRACKING WORKS WELL. FOR A HEATED SLAB TO OVER COME A 10" AIR SPACE, THEN HEAT A FLOOR WOULD BE VERY IN EFFICIENT. YOUR SPACING WOULD HAVE TO BE TIGHT, PLUS YOUR WATER TEMP WOULD ALSO HAVE TO BE BOOSTED UP HIGHER THAN NORM. BOTTOM LINE IS IT WOULD COST ALOT TO RUN, AND NOT WORK WELL.
GOOD LUCK
STEVE

John Felciano

Interesting

Thats a great idea,have you ever run the numbers?

Unknown

say it's a 100 sq ft room, and we can get the slab temp up to 95. 100x(95-70)/R... guess an R 3, perhaps?

that's about 8 BTUs/sq ft. not a robust calculation but a ballpark anyway. I'd be comfortable working in that ballpark for estimating supplemental or what have you, at least.



To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"