Dark lines through middle of floor

Q: I have just had my upstairs pine floors professionally refinished after removing carpet. Afterwards, there were think blackish lines through the middle of the floor. The refinisher said that this was due to the floor being cut when the carpet was installed and it cannot be sanded any further.

Basically, there is nothing he can do. Any perspective?

A: It is quite possible. A carpet installer typically uses his razor knife when cutting and doesn’t usually show any respect to the floor below. Deep knife cuts in wood often cannot be totally removed. If this open wound has also been subjected to moisture through carpet cleaning for example, the wood itself can become stained.

Another event can happen that can bruise the wood and leave it permanently marked. Dragging heavy furniture across a floor. In compressing the wood fibres, they become darker and won’t go away, even with sanding.

Related Q: I just refinished old oak floors with oil varnish, a clear semigloss. What I thought was a good sanding job had a couple glaring misses – with one coat varnish, fine lines appeared that look like they could have been inflicted when layers cut-out carpet sometime in the past. They show as very dark fine slices. Any remedies?

A: Unfortunately, those cut marks carpet layers cause are made with a razor knife and often they cannot be completely removed. They are too deep into the wood.

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