Thank you for your website, it has been a great help.
We have new oiled oak floors. The workers who were fixing other parts of the house have created lasting water spots on the floor. They have now said they will have to sand the whole floors to treat those spots.
Is that accurate? Does that reduce the value of the new floor?
Our answer depends on two - three issues:
how long the new floor has been down, how long the spillage has had time to cause 'damage' and if the water was polluted (like leaks from central heating radiators) and if any extra oil or maintenance products has been applied before the spillage happened.
It could be that the oil has protected the wood from definite staining and that the 'stain' sits on the oil/wax. Rub a small part of the stain with steel wool 0000 to see if this is the case. If so, rub the whole area down with steel wool and apply either the used oil or a suitable maintenance product.
If the water has stained the wood itself then light sanding (locally) is indeed needed. Be aware that water spillage can cause very deep and dark staining of Oak.
Because your floor has been oiled local sanding is possible. After sanding oil has to be applied again but compared with lacquer or varnish the 'new' area will not create a 'patchy' appearance.
Any reduction in value of the floor depends on how deep (if any) the stain has penetrated: how much has to be sanded off locally, reducing the thickness of the boards in that area.
Hope this helps.