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Water Damaged Countertop Seam

There are several ways to repair a water damaged area on a plastic laminate countertop where liquids have seeped through the seam and caused the particle board to swell underneath. The methods used to repair the raised spots are going to vary depending upon the style of counter top that you have. All laminate counters are not manufactured the same way; so there are various solutions to this problem. The design of your kitchen and the extent of the damage will determine the way that the repair will have to be done.

There are three basic Formica counter top designs, post form, beveled edge and the traditional square edge style. I am going to offer suggestions for repairing each one.

Basically any plastic laminate countertop which has a special type edge is going to need to be completely replaced if water has damaged the seam area. This rings true for wood edges, beveled laminate, Corian or solid surface type edges.

The culprit that caused the swelling is the particle board underneath. The laminate seam can’t withstand the rising pressure the moisture creates as it combines with the pressed wood. That is why your once beautiful Formcia, Nevamar, Pionite or Wilson Art plastic laminate top needs a repair.

Repairing Water Damaged Post Form Countertop Seams

The only effective and professional way of repairing a water damaged post form top is to replace it with a new one. Throughout the years, it is this style of tops that has proven to be the most absorbent and in turn has displayed noticeable damage in many kitchens that I have seen.

This style of counter has a rounded front edge. This design always has the backsplash molded into a curved shape as well. In other words, the splash is not a separate laminated piece.

The sad part about post-form countertops which have swollen due to water absorption is that it could have been avoided. If the cabinet/countertop installer had used a sufficient amount of caulking in the seam area, when the two pieces where joined together, the damage would not have occurred.

How to Fix Beveled Edge Water Damaged Countertops

You will pretty much have to replace your plastic laminate countertops if the water damaged area of the countertop is where the beveled edge meets the flat portion of the top. The same is true if you have a large place on the flat portion of the counter where two pieces where joined together that has swollen.

The majority of these countertops, in recent years, are custom manufactured by the cabinetry company that is building the kitchen. Although many of the beveled edge countertops that consumers get through Home Depot or Lowes are provide by mass production facilities.

Custom fabricators just purchase the beveled laminated edges and apply them to the counters as they are building them. The angled edging is actually a piece of molding made out of medium density fiberboard; that’s susceptible to the possibility of being damaged from liquid absorption.

Square Edged Counters with Water Damaged Seams

It is this style of Formica (or “plastic laminate”) counters that offers some hope if it has sustained water damaged. The seam will have to be completely reworked by re-laminating the entire countertop. The good news is that you will not have to tear out the entire kitchen counter in order to repair the damaged seam area.

Here again, the raised area could have been prevented by not using particle-board underneath the laminate when the top was manufactured. Plywood is the best choice for these custom fabricated tops. Some fabricators use aluminum foil to seal the particle board with, in the seam areas, prior to contact gluing the Formica into place.

My suggestions are not to be taken as rules. It is possible that your kitchen tops can be repaired without having to replace them entirely. As previously mentioned there are many factors that will affect the final decision a professional will make.

Once you have a professional cabinet or countertop manufacture evaluate your water damage situation, an accurate determination can be made as to how the repair will need to be done. Just about any real repair technician should know how to fix your damaged Formica seam area within a few minutes of the examination. Whoever you contract to rework the swollen top, make sure that they put into the proposal that they will either use ply-wood on the new top or seal the particle board prior to repairing it with the new mica.

  1. david brueggemann
    August 15th, 2010 at 06:40 | #1

    Would the installers be liable for replacing the damaged countertop since they didn’t use a sufficient amount of caulking in the seam area?

  2. admin
    August 16th, 2010 at 08:40 | #2

    The chances are very slim that a countertop will begin to swell from normal use before a cabinet companies warranty obligation expires.

  3. shannon
    September 3rd, 2010 at 05:47 | #3

    Your information regarding water damage is slightly incorrect. Water damage in postform countertops is an issue that has existed since the product was developed. An installer can try and caulk, seal etc… till the cow’s come home. The substrate under the laminate is particle board and extremely vulnerable to moisture damage. NO MANUFACTURER, fabricator or installer warranties water damage – industry standard. If you are concerned about water damage….choose another product – even self-edge laminate is a much better choice. If you research Wilsonar, Formica, Hartson-Kenndy (all major manufacturers or distributors – no warranty on moisture damage.)

  4. Joseph
    December 5th, 2013 at 15:04 | #4

    I am hoping to find help with my particle board countertop. When it was installed, the worker cut the opening for the sink a little too much on one side. I want to keep moisture out of there so that it doesn’t get damaged. How can I seal this?

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