radiant heating for 20 wide universal

[KevinS]

I am planning on building the 20 wide universal on wood post and beam and i was wondering if i could use 1 1/2 gypcrete over the subfloor for the radiant floor system.  I am concerned about the weight of the system with the wood structure.  Thanks

[John Raabe]

It looks like that layer of Gyp-crete will add about 12 psf to the dead load of the floor (the normal structure is usually rated around 10 psf). See: http://www.maxxon.com/gyp-crete/data

I would suggest a review with a local engineer to check the soil loading and whether the joists, beams and piers need to be upsized.