Here in the U.S., pretty much all the houses, even those that are made of brick, have framed floors, meaning there are 2 x (usually 10) joists from one side of the house to the other and then OSB subfloor on top that, then finish flooring.

I understand that it is different in big buildings where they actually have concrete floors between stories.

Now, I am contemplating a house design. I would like to run PVC pipe through the floor in the finished basement so that I can have solar heated floor that water runs through. The basement floor would have to be concrete anyway. But I would also like to have the same pipes heating the second story and, with joists going across, it will be difficult to run the pipe in a spiral pattern. So I was thinking, why not make the basement basically a concrete bunker with a concrete slab on top, as opposed to just having beams and plywood separate it from the second story, and have pipes run through that platform. I understand the slab form would have to be supported by posts from the basement and have elaborate reinforcement. The basement walls would be concrete blocks.

Since I really don't know anybody who built a single family residence this way in the U.S. (even though in the rest of the world EVERYBODY pretty much does), I was wondering about the pros and cons of this design. From there on upstairs, the house would be regular stick framing construction [2x6 (cold climate, more insulation), OSB sheathing, cedar siding etc).

  • It's not common to see solid wood joists anymore. TJI joists or engineered trusses have mostly replaced them. Back on topic... This is typically done with a poured gypsum floor over wood subfloor. Your pipes are laid and the slurry is poured over it, to maybe 1-1/2" thick. Of course the floor system must be engineered for the weight. Back off topic... I don't think "balloon framing" is what you think it is (an archaic technique). – isherwood Dec 5 '16 at 15:08
  • Yes. Did you read it? "It uses long continuous framing members (studs) that run from the sill plate to the top plate, with intermediate floor structures let into and nailed to them." No one frames wooden walls multiple stories at a time anymore. – isherwood Dec 5 '16 at 15:20
  • Balloon framing is a great technique with green, unseasoned lumber as it was back in the day. Nowadays it is a problem for fire blocking. Today's platform framing addresses this as it is built. That is off topic though. isherwoods comment about "Gypcrete" it what has been used. There is plywood that is available that has precut tracks to let the specified diameter of pipe lay in. It also has a formed aluminum reflector set across the face to aid in keeping the heat uniform. I have also made it myself, not with the aluminum of course.... – Jack Dec 5 '16 at 15:32
  • I corrected it to "carpentry framing construction". is that better ? – amphibient Dec 5 '16 at 15:33

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