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Question:

New Hardwood Floor Installed But Still Warped Our house was built in 1994. The wood floors were trouble free until an in wall water line break flooded the area between the sub floor and the wood top floor. Result; our beautiful wood floors warped and had to be replaced. Water problem fixed and new flooring installed in April 2001. In summer of 2001 new floor begin to warp. Installer said this should correct itself in winter heating season. In winter problem partially resolved.

Floor warping receded and was almost normal. In summer of 2002 floor warped again. Installer said problem was humidity under house (original floors from 1994 to 2001 never warped from under house (crawl space) humidity. Installer said seal exterior foundation walls, lay plastic on ground and provide forced air ventilation in crawl space. All done in spring of 2003. In summer of 2003 floors warped again. Installer says not his problem and has no idea how to fix problem. House has been thoroughly checked for any other water leaks. None found.

Any ideas or suggestions would be appreciated.

Thanks

Paul

Answer:



Dear Paul

I'm sorry to hear of your dilemma, but I do love a mystery. I will make a few guesses here and now, at first. But I will have to know more about the floor, so I'll ask you a series of questions at the end of this email.

Warping of wood floor always begins when one face (side) of the floor board has a much higher moisture content than the other. For instance when a table is repeatedly wetted on it top surface, it will warp on the edges upwards. This is called "cupping". If both surfaces experience a wetting, the surface that's stays wet longer will cup. If the floor remained wet under the floorboards the result in your case might have been a crowning (convex) of the top surface (or really a cupping of the underside, stay with me).

There are exceptions to this, as an older floor with large gaps will warp differently than a brand new tightly laid floor. The severity of warping also depends on how restricted the wood is.

It is possible that the hardwood floor contractor did not wait until the subfloor was completely dried out. It can take up to a month when the floor and subfloor and joists have been soaked. Particularly in humid weather. The flooring contractor should have tested a dry part of the house's hardwood floor for the EMC (equilibrium moisture content). This reading would have been the norm for your house. He would remove all the old hardwood, and test the subfloor about twice a week, until the soaked subfloor EMC came back to normal for your house. In the mean time he would have delivered the wood to be installed, but stored it in an unaffected part of the house. This procedure is assisted by fans, the AC and windows open just a little. Ventilation from down below would have been just as important at this stage, because typically during minor floods, the underside of the subfloor is wet also.

A good,and fast drying out of the floor would have also prevented any mold from growing. A big concern these days especially in the Southern states with long periods of hot humid weather.

Now, let's say the flooring contractor rushed though these steps and installed the new hardwood on top of a subfloor with just a slightly higher EMC (5-7%). Then the underside of the new wood may have taken on this excess moisture in just a few days. The new hardwood would have cupped a bit in this case. But if the floor guy chose to ignore this and then sanded the wood flat, later the new wood would have flattened itself out and caused a crowning of the wood, as the underside returned to flatness, thus cupping the surface. Sounds weird but it happens.

This is just one of many possible scenarios that can happen to a wetted wood floor. A crawl space under a new hardwood floor puts another factor into the equation.

So here is a series of questions that you need to answer as best you can so I can come up with a viable solution.

Did the flooring contractor rush though these preparation steps that I have outlined ?

Did the floor warp in a crown (convex) or a cup (concave) when it was first damaged. What kind of finish was on the old floor and what condition was it in ?

And most importantly, is it cupping or crowning now, and how much ?

Does the new floor have a high gloss oil poly finish on it, or a water based finish ?

How many coats of finish ?

What was the species of the old wood and the width and thickness ?

What is the species of the new wood and the width and thickness ?

Is your subfloor made of plywood or OSB (oriented strand board-recognized as chips or large flakes of wood on the surface of the subfloor board, you'll have to see this from below) ?

And lastly can you send a digital picture of the floor at floor level, so I can see how severe this is (it's the middle of the summer, so it should be at it's worst).

If you can answer each and every question, I can give you a more accurate answer.

You may also find these articles helpful:

1. Installing Hardwood Floors On Concrete Slabs

2. Hydronic heating under your wood floors

3. How To Sand Wood Floors Without Leaving Machine Marks

4. Plank Floor: What Special Considerations This Type Of Floor Raises

5. How To Take Care Of Your Health And Safety when Installing, Finishing, Repairing or Cleaning your wood floors