Cabinet Door Shrinkage and the White Line
One of the most common complaints about cabinetry through the years, especially in the dryer parts of the country like Colorado, is that the panels in the doors shrink and a white line shows up down the sides of the panel. Why is this? Raised panel doors are made of a wood frame and a separate center panel. This center panel is not glued in place and “floats” in the frame. This is done to allow the wood to shrink and swell with changes in humidity. If it was glued or held in place by pins or brads it would create havoc with the frame when it expanded or contracted and contort the door so that it wouldn’t open and close correctly.
When a door is stained after it is assembled the stain does not get all the way back into the edge of the panel concealed behind the groove in the frame. Thus, when the door panel shrinks you see the unstained area which looks white compared to the stained parts around it. This is most likely on doors that were finished during a time of high humidity or the door had a higher moisture content.
Note that this happens on panels made of solid wood. Doors made with veneered panels don’t typically have this problem because the core material of the panel is more stable and not affected by humidity.
Manufacturers who make cabinets doors with solid wood panels have several ways they deal with this. Some companies who stock doors ready for cabinets will store them in warehouses maintained at a specific humidity level. Many who make their doors to order will allow the wood to season and then test the raw wood for its moisture content to assure it is at an optimum level to avoid shrinkage. However, despite their best efforts these measures are not certain to control the issue. Due to the fact that a paneled door is made up of separate pieces it is impossible to completely seal the panel from air infiltration when they apply the finish coats. So, no matter how well prepped the panel is when air gets into the panel it changes the moisture content.
If a door is made in a moist climate, as is prevalent in many parts of the country, and then shipped to a dryer place it will most likely shrink (up to ¼” in some cases!). Once it is in the home it will then shrink and swell with the seasons. Humidity levels are typically lowest in the winter and many times the white lines only show up then and disappear in the summer.
The only sure cure for this is to stain the panel prior to assembly. However, I know of no major manufacturer that does this (at one time Wood Mode did but I don’t think they do anymore). It is simply not practical for them and they would have to charge a great deal more to do so because of the many additional steps it requires.
The only companies who can do this practically are small shops that can afford the time to do so. Here at The Cabinet Guy we do stain all panels prior to assembly on the doors that we make so this isn’t an issue for us or our customers.
If you do have these white lines you can help conceal them by wiping some stain on the line using a small paint brush or a stain pen (available at home centers and paint stores or from your cabinet supplier). After you have stained the line and it has dried you can bring up the gloss by applying some paste was or brushing on some lacquer or other type of varnish.
One other note. I recently had a client who had some cabinets with doors that were made in China. Most of the panels had shrunk by 3/8” to ½” and many had developed severe cracking. They were worse than anything I had ever seen. The cause of this turned out to be that they were shipped by boat in a container from China. These containers are huge steel boxes and during their 2-3 week journey the temperature can reach 150 degrees causing them to dry and shrink excessively. Fortunately most doors are still made in the USA and it is not likely that Asian manufacturers will corner this market for many practical reasons.