I have noticed that one of the joists in our crawl space has a small crack in it, and near to it are some small (1-2 inch long) fissures. I didn't notice it at the time, but in the photos (see below) the small fissures appear to have some yellowish liquid inside.

I would like to know if this is a natural feature, or a sign of insect damage. I couldn't see any other signs of termite damage (e.g. mud tubes) and the rest of the joist looks fine. I tried to stick a screwdriver into the joist but it seems to be solid on both sides, and the bottom, near to these features.

I would be grateful for any suggestions on what this might be.

Many thanks.

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2 Answers 2


The grooves in the second picture appear to be pitch pockets which are fairly common in softwoods and construction lumber.

The fact that the pockets contain a noticeable amount of resin may indicate that the lumber was not thoroughly dried (as is with most construction lumber). Fast or uneven drying is also likely to cause splits or cracks as wood shrinks and expands significantly depending on its moisture content. The possibility of these cracks, however, is usually accounted for in designs and most splits stop at the center of the beam. See here for details.


Some of those look like they could have been worm holes in the tree before the thing was cut up into planks.

Other parts that look more like deep scratches could have been caused by the planks being dragged along a truck bed or other surface where there there was gravel particulate.

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