Expansion cracks (reasonable)

Description
'Reasonable cracks' are caused by normal expansion and are not excessive.

Wider boards will have naturally wider cracks, while narrower solid wood flooring boards, solidengineered and engineered wood floors will generally have less expansion across the width of the board, and as such will have smaller expansion cracks.

Possible causes
Loss of moisture or drying out of wood flooring is the most common reason for individual floorboards shrinking, which is then likely to result in cracks appearing.

Most cracks appear during seasonal changes. They tend to occur predominantly during dry months, or during winter months when central heating systems are switched high.

Likewise, during more humid periods the extra moisture in the atmosphere tends to be taken up by the wood flooring - and hence cracks close up during these times.

Remedial tips
If significant shrinkage occurs, consider putting moisture back into the atmosphere during dry periods - for example, by boiling a pan of water, turning off a bathroom extractor fan or placing water bowls by central heating radiators.

If this concerns you as a prospective purchaser of wooden flooring, we recommend you should opt for a narrow board - or better still, opt for a solidengineered or engineered wood floor and install it using Sikabond T54 and a full stick down.

If expansion gaps are a problem then the key is to try and maintain consistent and constant relative humidity (RH) of about 50% RH at 18-20 degrees Celsius. This is the ideal environment in which to maintain a wood floor, and provide good dimensional stability in the floor.

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