How Humidity Affects Hardwood Floors (And What You Can Do)

Hardwood flooring has a natural warmth and aura that is pretty much irreplaceable. 

Unfortunately, humidity can ruin it by causing cracking, cupping, crowning or buckling. 

When humidity is high, hardwood flooring will soak up that moisture, causing it to swell and distend; when low, the dry air draws moisture from your floor, causing it to shrink. While this expansion and contraction are normal, excessive change can cause long-term problems. The trick lies in maintaining the ideal humidity within your house, which usually ranges between 35% and 55%.

Effects of Humidity on Hardwood Flooring

Effects of Humidity on Hardwood Flooring

Humidity levels higher than 55% can cause the following problems

Cupping: When wooden planks swell from excess moisture and push against one another, their edges become higher than their centre. There are many reasons for cupping, most related to excess humidity. 

If cupping occurs, it’s important to identify the reason and fix it immediately, or you may have to replace the whole floor. In some cases, using fans and/or dehumidifiers can restore the planks’ shape and structure.

Buckling: This is the result of excessive moisture in your hardwood floors causing the planks to pull up from the subfloor and buckle. When the humidity level drops back to normal, the planks may shrink back, but chances are that you’ll notice spaces between the boards.

Crowning: This is the opposite of cupping, where the centre of the board is higher than its edges. This happens when hardwood floors are left wet for too long or are sanded soon after cupping. 

Cracking: When excess moisture or humidity causes wooden planks to expand drastically, the adjoining boards start pushing against each other. In some cases, this pressure can damage the boards’ structural integrity, resulting in cracks.

Humidity levels lower than 35% can cause the following problems

Gapping: In winter, when heaters are used and the air is dry, hardwood loses some of its moisture and shrinks. As the planks contract, the gaps between them increase and expose your floor to further dust, dirt and allergens. 

Splitting: As the wood dries out, it becomes brittle, resulting in cracks or breakages along its grain. This can cause splinters or fragments to stick out, posing a threat to users or family members. This damage is permanent because once the floor finish is damaged, the wood beneath is no longer protected. 

Tips to Protect Your Hardwood Floors Against Humidity

Here’s how you can protect your hardwood floors against drastic changes in humidity:

  1. Clean Carefully

Only use a certified hardwood flooring cleaner and avoid using water under any circumstances. 

Immediately clean spills with a dry, cotton cloth to avoid it seeping into the wood. Aside from cracking and cupping, spills can also cause mould and mildew.

  1. Install a Humidifier or Dehumidifier

Install a humidifier or dehumidifier, together with a humidistat or hygrometer. This will help you maintain optimal humidity and avoid hardwood damage. 

  1. Choose the Right Flooring Contractor

Make sure you choose a professional hardwood supplier and installer. If hardwood isn’t stored or installed under proper humid conditions, it will most likely cause flooring issues. Talk to your flooring contractor about acclimatization, which is the process by which your hardwood adjusts to your living space. 

You’ve spent thousands of dollars on your hardwood floors, so don’t ignore the factors that can damage them and affect their longevity. With a little care, consideration and prevention, you can enjoy beautiful flooring for years.

Amazon Hardwood Center