Why Do Wood Floors Buckle?

In this article we’ll look at why a wood floor of any type buckles. We’ll be looking at how a floor can buckle or lift due to poor installation, poor sub-floor preparation and generally how in-home environmental climate problems can make this happen..

Buckling can be anyone’s worst nightmare, but it can also be fixed if caught in time. It’s fair to say, if you have a solid wood floor that’s been fixed down with nails or glued to the sub-floor, if buckling has occurred, it’s probably to late to remedy the issue and time to think about a complete rip up or part replacement. This is an ideal circumstance when spare planks may come in handy.

Buckled floor due to excessive moisture coming from the sub-floor.The most common reason for buckling is lack of an adequate expansion gap around the perimeter of the floor. This can even mean small restrictions. For instance, if a floor is laid with adequate expansion all the way round the room but in one or two places it has no expansion gap, buckling can ensue.

A floating floor however, can be a different matter and can be rectified if caught in time. This would be carried out by cutting out the places where the floor is grounding (hitting a solid surface). If there’s no visible damage to the boards like cupping, crowning, lipping etc and there’s simply a bump in the middle of your floor, it’s time to get to work with a multi-tool and/or plunge saw (One that the design allows the blade to go close to a wall) start the arduous task of using a chisel.

The reason for buckling is often down to poor installation. It’s a simple part of any installation, leave an adequate expansion gap! However, we come across this problem more than we’d like, as fitters seem all to willing now a days to cut corners in an attempt to increase profits. A common story. If you have a fitter in your home and want to check he/she knows what there doing, check for expansion gaps. This is one of the easiest and quick visual checks to carry out.

The way expansion works, is generally to a ratio i.e. A large room will need more expansion than a small room. In other words, when a wood floor is interlocked, you have to remember that each plank will expand when the room humidity increases. So, if you have  30 rows of flooring and each row expands on the width by 0.5 mm, this would mean the entire floor may expand by 15 mm (this is just an example and is not exact as different floor types and densities expand and contract at different rates. However, the ratio isn’t to far of the mark for most floors).

So, if you have a small room or even stairs to fit, we can see that only a very small amount of expansion clearance would be required. You wouldn’t leave a 15 mm gap each side of each step now would you, and as pointed out, you wouldn’t have to.

Now expansion rates will run in conjunction with air humidity and temperature. The measurements above relate to an average of a balanced ambient temperature (approx 20C) and an air humidity of between 45 – 55% being maintained. Occasionally you may find these fluctuate outside of normal conditions, maybe caused by an exceptionally heavy rain fall or leaky heating pipe etc. This will not always cause the floor to expand excessively, as mentioned, different floors react differently and some can be a lot more hardy than others.

If the conditions change, and the humidity raises beyond normal living conditions, this can have the effect of the wood expanding beyond it’s expected parameters. So to say the reason for buckling is always an installation fault is incorrect.


If you find your floor is starting to buckle/lift, firstly the best thing to do is find the pressure points of where the floor is hitting the solid perimeter and assess why this is happening. Purchasing a basic hygrometer to measure the rooms humidity will give you an idea of what the atmosphere is doing. If the air is too moist (over say a maximum of 65%) it may be worth hiring a dehumidifier to try and stabilise the humidity to an acceptable level in the short term and finding out what has raised the humidity in the first place.

It’s worth mentioning that not all homes are automatically ok to have a wood floor. This depends on many factors and a proper assessment of the property should be carried out prior to purchasing your would floor. An ideal assessment would consist of monitoring the air and temperature over a number of days and taking readings prior to fitting your new wood floor. 


© Copyright 2013 Wes, All rights Reserved. Written For: Fitmywoodfloor

I am a Pergo trained professional installer of 20 years. I've been up close and personal with lots of floors and have the knobbly knees to show for it...Should you have any questions or comments please feel free to add them below. Thanks for taking the time to call by and I hope the information you've found has given you some insight!........................................................................................................................................................................“When you click on links to various merchants on this site and make a purchase, this can result in the site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network, amazon.com, amazon.co.uk, amazon.fr, amazon.de, amazon.it, amazon.ca, affiliate window network.” This statement is to comply with current internet regulations regarding transparency to consumers.

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