Faded Hardwood Floor?

[julvr]

My brother has Maple Hardwood floors in his place, with a heavy coat of clear poly-urathane to protect it. On this floor is a grand piano. The Piano rests on three felt-bottomed coasters.

We recently moved the piano, and discovered that everywhere there was coaster, the wood underneath was lighter than the surrounding wood. (in a very clearly defined shapes). The floor itself is still perfectly smooth and unmarred.

I was wondering if anyone had any ideas what caused the lightening (or possibly the lack of darkening)? My first thought was it had something to do with light, but the areas under the rugs which were there the same amount of time, do not show the same lightening. Is it possible that some chemical in the felt sept through the polyurithane, and stained the wood???

John

[B a r r y]

Many unstained woods darken when exposed to sunlight. Many urethanes "amber" with age and exposure to light.

If you leave the lighter area exposed to sunlight, it will probably change to the color of the rest of the floor all by itself.

I'd allow the light to hit it and do nothing.

Barry

[Leon]

The covered area of the floor stayed the original color. The rest of the floor darkened from the light. With time and light, the spots will also darken. I would let nature do its thing.

[fredfighter]

It would seem likely that the reast of the floor, or finish on it, darkened over time, rather than the floor under the coasters lightening.

Two things cause wood to darken over time, or in some cases (walnut) lighten. One is exposure to light, the other exposure to oxygen. It appears that you brother's floor demonstrates that it is exposure to oxygen that causes maple to darken over time. The coasters no doubt impede the diffusion of oxygen through the finish beneath them far more than the rugs.

BTW, it is primarily oxygen that lightens black walnut. Left unfinished it can turn almost amber in five years or so.