Radiant slab and interior LW CMU walls
Radiant slab and interior LW CMU walls
(OP)
Hello all. I am currently working on a project with a radiant slab installation. The mechanical engineer is wanting to use a reflective radiant barrier (bubble wrap/foil/bubble wrap) directly under the slab that has an overall thickness of 3/8". We are looking to use an 8" thick slab, reinforced with #5's @ 18"o.c. each way. The kicker here is that we have interior non-load bearing lightweight cmu walls, 10'-0" tall, that will bear directly on the 8" slab. Our fear is that with the possible compressions of the radiant barrier, which the manufacture says is not a concern, we will get differential settlement possible at the cmu wall locations and the unloaded interior slab locations. My question is if anyone has had any experience with this type application or any references or recommendations on the topic.
Thank you.
Thank you.






RE: Radiant slab and interior LW CMU walls
1. The difference between lightweight and normal weight CMU have minor differences in wall weight.
2. A wall laid in running bond does actually function as a beam, distributing the loads over a much larger area along the length that reduces deflection of a slab it bears on.
If the block are laid in stack bond, the benefit is reduced.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Radiant slab and interior LW CMU walls
RE: Radiant slab and interior LW CMU walls
Dick - not trying to pick on you but whether stack or running bond, the bubble wrap would essentially see the same load. What you are referring to is that with running bond, any soft spots along the wall length would be somewhat better bridged by the wall stiffness. With a uniform subbase stiffness, there would be no difference in pressure.
RE: Radiant slab and interior LW CMU walls
I also erred when I used old term of "stack bond" instead of the correct term, which is "other than running bond" that is now used in ACI 530 to give definition and clarify various bonding patterns that may not be "running bond", which may be changed in the future.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.