Causes for Cupping in Hardwood Floors.

Information Taken from the N.W.F.A. Technical Publication,

 

"Cupping and crowning" are common complaints that develop with high humidity. Both problems occur across the width of the flooring material.

Cupping is when the edges of a board are high and its center is lower.

It can occur after water spills onto the floor and is absorbed by the wood, but high humidity is more often the cause.

 

If the wood expands significantly, compression set can result as the boards are crushed together. deforming the

boards at the edges. Cupping is caused by a moisture imbalance through the thickness of the wood: The wood is wetter on the bottom of the board than on the top. The moisture imbalance can be proven by taking moisturemeter readings at different pin depths.

identify and eliminate the moisture source.

 

Today we done moisture readings in a 2 1/4 x 3/4 solid red oak hardwood floor the moisture content on the surface was 9% as we took readings deeper into the wood the moisture content went up to 13% the floor was cupped in all the rooms.We did find some drainage issues around the house and some pipes leaking in the crawl space.These problems need to be corrected prior to sanding the hardwood floors.Sanding a hardwood floor that is cupped,with high moisture content will cause the hardwood floor to crown when the boards dry out.
Always indentify the cause of the moisture and correct the problem prior to doing any work on your hardwood floors.