I need some feedback. The project I am currently doing will have hydronic radiant heat tubing installed underneath the existing 1×6 diagonal subfloor (1920’s house). Finish flooring will be 2 1/4″ strip oak, finished in place.
Radiant sub says he’d prefer the flooring to be installed first, to minimize the chance of a wayward flooring nail puncturing the tubing. Since I normally install hardwood after drywall & before trim, a puncture would suck. So, not an unreasonable request.
Hardwood guy says he’d like to break the bundles, scatter them and let ’em sit for a week or so with the radiant heat on, to get everything acclimated and reduce the chance of shrinkage. Not a bad call, since we’re just outside of DC, and it’s hot and humid most of the time. Having to fire up the heat and stay off the interior for a week in the middle of summer would be a drag though.
Seems like I have a couple of options:
1. install tubing now & flooring when I normally do and take the risk. Maybe mark the rosin paper or felt with the tubing locations to minimize risk.
2. install tubing now & flooring AFTER trim (it will into autumn then, so less of a PITA)
3. install wood now, before drywall & other trades. Protect it with masonite. Hope it doesn’t shrink like crazy after the heat comes on.
3. add 1/2″ plywood to entire subfloor to remove risk of stray nails
4. use quarter or at least quarter/ riftsawn mix on the oak to minimize shrinkage.
This is the first time I’ve done the radiant on a job, and I just don’t want to eff it up and box myself into a corner.
Anyone got any hard-earned wisdom they’d like to share?
Thanks,
Mike
Replies
Moisture content of the wood is much more important than whether the heat is on or not. You want to install for an average moisture content that will be seen of the course of the year for your area, in this house. This relates to humidity.. I can't translate exactly, but the wood guy should be able to.
How much of an issue wood selection is depends a bit on load. Heat loads are very important. Make sure they are calculated so you know what kind of surface temperature you're expecting. If it's an old house, your loads may be high. Or not, depends on the nature of the rehabs taken.
Quartersawn is always a better choice than plain sawn, but not always necessary.
hardwood installation should use nails short enough not to penetrate the subfloor. Risk gone, lots of nail grinding avoided.
Try to keep your water temps as low as you can, and use outdoor reset at least!
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I live about 60 miles from you and have 5500 sq/st of hardwood with RF heat and it is wonderful.
I marked the paper before nailing the floor and also had the tubing pressurised with and alarmed pressure gage. I never hit anything so don't know if the alarm worked of not.
I have the tubing on 8" centers and run a water temp of around 105. This is a 3 year old ICF house and every room is on it's own zone and every wall and floor has all the insullation that would fit. My heating cost last winter was about $350.