Gapping on Wood Flooring - Part 4 - Normal Seasonal Movement


Movement of flooring is frequently seen during changes in conditions. This is identifiable by small gaps between flooring elements, that tend to be less than 2 mm. It is common for these gaps to become evident during the drier winter heating period. This can be seen coinciding with small changes in the width of the individual flooring elements. The shrinkage is proportional to the width of the flooring elements and the degree of moisture loss.

Gapping on Wood Flooring


Due to wood being hygroscopic material, it suffers from expansion as it gains moisture and subsequently shrinks at it loses it. As a rule of thumb, the outdoor atmosphere is drier during the winter months and considerably more humid during the summer. Changes in moisture content and dimension occur in response to the humidity and to a lesser extent the temperature of the environment.

On-Site Diagnosis

To ensure that the correct solution for the area of concern is reached, you must accurately identify the issue. Something to look out for with a problem such as this would be the size of gaps between boards and do they correspond to the degree of shrinkage of individual boards. Check the time period during which shrinkage occurred, and present atmospheric humidity.


Normal seasonal gaps must not be filled, as they are needed to accommodate the seasonal expansion changes that may occur. Gaps will typically decrease in size during the more humid summer period.


Unacceptable shrinkage can be avoided by selecting a specie of timber which is suitable for the conditions. Additionally, it is advisable to take note of the flooring width and moisture content for the environmental conditions.

  • Where a wider than normal temperature or humidity range is expected during use, select a small movement classification timber as well as a narrow width board. Alternatively you could choose an engineered product as it has qualities more suited to the conditions. These will help to avoid any problems that may occur