When is it safe to live in our home? We had a company refinish ours wood floors. They used two coats of polyurethane.

Asked by Eric Feldmann
Elmhurst, IL

We made a mistake and didn't research ahead time, we should have done water based. We have twin boys 5 yrs old, dog and cat, might have more kids. I am venting the place out, but now feel really stuck, we just bought the home ( we are living in another home now). I think I can get the smell out in 5 days, but I wasn't sure about the off basing voc's that might linger or how to get rid of them sooner. All the flooring is on the first floor, upstairs where we will be sleeping is carpet we just had environmentally cleaning done on. Thanks for the help. I love this website and will use it first next time. 


This is a common question and fortunately, there is an answer, although it is not so common.

Water-based polyurethane isn't automatically safe

Many refinishing contractors continue to swear by oil-based polyurethanes, however, most now use water-based polyurethanes.

However, just because a polyurethane is water-based does not make it safe.

  • A water-based product simply uses water as the carrier for the polyurethane solids instead of oil.
  • It says nothing about any of the other active ingredients, namely, volatile organic compounds (VOCs), solvents, odor-masking agents, or a number of other chemicals that may or may not be hazardous to your health.

Due diligence required

To understand what is inside the container and how it affects your health, you need to:

  • read the label,
  • research the chemicals listed on the material safety data sheet (MSDS) at ( and
  • always test the product in a small inconspicuous area first, especially if you are chemically sensitive.

For more information about VOCs read "IAQ and Your Health: A deeper look at VOCs and formaldehyde emissions." This is a white paper I wrote on the topic.


Unfortunately, you found out the hard way, after application, that you could not tolerate the off-gassing of this product.

In general, off-gassing may continue for days, weeks and even months depending upon what was in it, how much was applied, what temperature and humidity are in the home and how tight the building is.

Usually the best way to mitigate the off-gassing of a finish that has been applied to a floor is to:

  • ventilate the room by opening windows,
  • turning on multiple fans,
  • turning up the heat, and
  • employing air purifiers.

All of these methods accelerate off-gassing but don't eliminate it at the source.


Another method called encapsulation seals in the off-gassing and is faster and more effective than ventilation.

  • AFM Safecoat is a manufacturer of encapsulating sealers which stop vapor emissions from porous wood, paint, polyurethane, and carpet.
  • After three coats, for example, their Polyureseal BP stopped off-gassing of formaldehyde by 100%.

It should be noted that off-gassing from organic and related sources, such as food, pet odors, mold and mildew contamination, cigarette smoke and fragrences can typically not be sealed.

Combine dilution and encapsulation for best results

We have found the combination of ventilation and encapsulation to be the best way to mitigate off-gassing of hazardous chemicals.

  • Every indoor air quality problem and every surface is different, so there are no guarantees.
  • But there are some basic rules of success outlined in this document: How to Manage Off-gassing.

Ideally, your experience will teach you the meaning of testing before you use any unknown chemical. A description of our approach to testing new chemicals is here.

If you have further questions, please call or email.


Joel Hirshberg
[email protected]

Tagged In: floor refinishing, hardwood floor refinishing

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