New Radiant Floor over old one
We would like to install a new radiant floor over our existing (but not working) original system. We want to stick with hydronic and are curious if people have had good luck with this retrofit. Specifically we are curious what the minimum floor space (depth) we can get away with is. We have heard that you can lay a slab over a new system that is anywhere from 1.5 to 3 inches thick. All comments are appreciated.
Thanks,
Gordon
I've done it. We managed to fit it into a 1.5" gypcrete slab on top of the old slab, which I cleaned and was in good condition. This thickness is dependent on the radiant tube sizes used, so yours may differ slightly. Adding floor tiles got us closer to 2" in the end. A few not-so-minor caveats:
All old flooring has to be removed,
The house has to be empty at the time of the install & pour,
You will have to redo your kitchen and bathrooms,
You may well have to reframe all your doors. Mine were all the code-minimum 6'-8" high before the pour, so they had to be raised.
Obviously baseboards and door thresholds need to be redone, as well as new flooring throughout.
The results are nice - we have an Eichler with new radiant heat the way it was meant to be, but it's not a project for the faint-hearted.
You should also consider replacing your domestic water pipes. Since you have the slab open, you can jackhammer a new route and lay new copper domestic water pipe IN the concrete (rather than below the slab in the dirt which accelerates corrosion). Many have had their domestic water pipes leak with age. This is the last time you have the chance to replace it in the slab before you add the radiant heat.
If you decide not to do this and have a leak in the future, you may have to run it on the roof. By putting it back in the slab, you have a piping system that will last the life of the house.
/Lynn Drake
Very few Eichler owners choose to do what you are considering. Lowering the ceiling height in part of your home to less than 8 feet can seriously affect the value of your Eichler. Your money will not be spent improving your home, only recovering your basic heating and domestic water. In this case, I believe you will end up with a net loss in the value of your home and improvement. That's a very high price to pay to keep your wonderful radiant heating.
