Engineered hardwood over Gyp-Crete and radiant
We have a 1920s home and are planning a pretty big remodel next year. We’ll also be removing our forced air heating source and adding a hydronic system to the house. The ground floor has a lot of variation (+/- 0.5″) and we would like it to be more level and consistent. I had thought about taking it down to the floor joists and sistering/shimming where necessary before adding a new subfloor.
I had planned to add radiators to the ground floor but have had some people suggest adding radiant coils and a gypcrete thin slab. Assuming the engineering can support it, this is a really attractive solution as we will end up with level floors and in floor radiant.
We love classic hardwood floors and I am worried we’ll be disappointed by the feel of the engineered flooring. I am convinced we would be happy with the look as I’ve seen many applications that look excellent.
What are peoples experience with floating, engineered hardwood over radiant? I’ve had people tell me it’s great and others tell me it’s a bad idea. Any bad stories or lessons learned? Any ideas for a totally different approach?
I will also say the joist bays are not very accessible from below. I’ve also considered warm board or something similar but it seems quite a bit more expensive and would be more labor intensive given the non-level nature of our ground floor. I’ve also considered sleepers in the gypcrete but most the info I’ve found suggests this is a troublesome approach.
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Some quick notes:
You will almost certainly need new floor supports to bear the extra load. It's a fair amount of extra dead load and 1920's houses aren't known for over-engineering.
In my opinion, the glue-down engineered hardwood will be satisfactory. But the floating stuff (at least the stuff I have experience with) has too much "squish" factor and doesn't feel authentic under your feet. My recommendation, go walk on some different options at a flooring store or get some references and walk on theirs.
No reason it won't work with radiant, just make sure a mastic (glue) is selected that can withstand up to ~120°F. Many of them aren't rated that high.
Radiant done right is fabulous, radiant done poorly is a disaster. I design these systems and I've seen plenty of both.
how "not very accessible" are the joists? If you are already putting in a new subfloor you may be able to first put in some insulation from above with the open floor and then run electric/hydronic under the subfloor and then be able to nail your flooring down into the subfloor.