We've been living in this house for 1.5 years and the previous owner had these floors installed. They're solid wood planks and from the state of them, they were installed at least 5 years ago. Last winter we noticed some separation around the heating ducts. The house has gravity heat, and the furnace is in the "basement" (cement lined hole under the house open to the crawlspace). The furnace sits directly under the closet that's adjacent to both rooms that are experiencing the problem.

This winter the separation got worse and in some instances is extending across the entire room. We were planning on refinishing them (one room with these floors has already been refinished as will be clear in the pictures), but we're afraid of expending the effort if this problem is only going to worsen. We'd also hate to rip out the floors only to experience this problem with the new floors.

I know expansion and contraction is due to environmental changes. We haven't added any sprinklers and this season hasn't been very wet so I don't think humidity is a factor. We did just have an extreme cold spell (which caused the furnace to run almost nonstop) and I think the floors worsened through that time. Another variable we've considered is that the previous owner never used the heat (it is southern California afterall, and the previous owner was an elderly English woman).

What are our options? Will this problem continue to get worse until the floor buckles, or is there a point where it will settle out? Are we being overly critical and just observing typical behavior within acceptable limits for wood floors? It hasn't separated so far that the tongue has separated, just far enough to slide stuff between. Thanks for reading this far, here are some pics of the problem:

The refinished floors:


The floors begging to be refinished (ack, pickled!):

That gap looks like it has filler to the left of the matchbook.

The floor has lost moisture and shrank. It didn't shrink evenly. Looks like a waterbased finish.


Is that a wall heat register?

There's no filler in the gaps, what you might be seeing is the crappy finish which seems to flake off once it gets going. The register is connected to a duct that leads to the gravity heat furnace. There hasn't been a large change in moisture in the house and this winter has been pretty dry. Is moisture the only contributor to this type of problem? This floor has been here for 5 years or more. The wettest winter in the past 10 years occurred 2 years ago and these floors didn't start separating then so I'm having trouble grasping moisture as the cause here, especially when the separation started right by the register.

It is not from a gain in moisture, but as you say it has been dry, it is from a loss of moisture and shrank. Wood is hydroscopic, meaning it swells with a gain in moisture, and it shrinks with a loss of moisture.

I guess you said loss of moisture in your first post and my coffee-lacking eyes didn't notice it, sorry. Is our shrinkage typical, or as a professional would you call that unacceptable? Is there a limit to how much the wood will shrink, or does this lead to buckling and other problems? If we go ahead and refinish them, should we try to fill the gaps or should we leave them so the floor has that space to expand when the humidity increases? Would a moisture barrier prevent this kind of problem (I doubt one was installed)? Thanks for your help.

I would wait for summer to refinish. Let the flooring and the higher humidity levels swell the floor back to an almost gappless floor.

Panelizing and Shrinkage due to heat at the register.

Thanks guys, I'll assume your simple responses mean this is nothing to be alarmed about.

You could try a couple of room humidifiers to help speed it along or help negate the effects that are already there from getting any worse. Pick yourself up a hygrometer (humidity measuring device) from a Big Box store and try to keep it your humidity in the 45%to 55% range. I know in winter hre in Michigan I can run humidifier on the furnace at its highest level....run room humidifiers and still never get it above 40 % RH.

Keep those cracks clean though so when it does swell back up you don't have dirt,food,etc...blocking the wood going together again.

Thanks Cyprus, I'll check into that. We probably will have to get humidifiers since this is Los Angeles and it sure doesn't get any wetter during the summer.

You have sub-floor movement and the reason for the wide gap.
The sub-floor could have lost moisture or the house settled.
The gapping at the heater............... well,,, the wood got DRY and shrank.
Wood is wood. Wood has natural characteristics that cannot be changed.
So... enjoy your wood floor and the imperfections that come with it.