How to fix swollen laminate countertop

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.

By Finn McCuhil Updated December 19, 2018

Heat and moisture are the two most common causes of laminate separation. Placing a hot pan directly on the countertop weakens the adhesive holding the laminate to the substrate. The particle board used as a substrate in most countertops is notoriously susceptible to moisture damage. Once exposed, it absorbs moisture quickly and loses its ability to hold a laminate bond. Successful repair depends in large part on reattaching the laminate as quickly as possible, before the substrate is damaged by water or high humidity.

1. Carefully lift the loose edge of the laminate. Use a putty knife to remove any debris between the laminate and substrate.

2. Heat the surface of the laminate with an iron or heat gun. When using an iron, place it on the “cotton” setting without steam. Heating the laminate softens the glue and frequently is sufficient to reestablish the bond between the laminate and substrate. The softening effect of a hot pan that can cause de-lamination in the first place can be used to repair the problem. Apply heat until the underside of the laminate is tacky.

3. Stack books or flat weights on the countertop and allow it to cool. If the laminate is loose when you remove the weights, you need to apply fresh adhesive.

4. Apply contact adhesive to the underside of the laminate and the top of the substrate.

5. Use a laminate roller or rolling pin to press the laminate against the substrate. Work from the still-attached portion of the countertop to the edge. This spreads the adhesive evenly and works any trapped air bubbles out from under the laminate.

6. Weigh down the repaired area with books or flat weights for at least one hour. Consult the directions on the adhesive container for curing time.

   Things You Will Need

   • Putty knife

   • Iron or heat gun

   • Contact adhesive

   • Books or flat weights

   • Laminate roller or rolling pin

   Aerosol contact adhesive is easier to apply in most repair situations than liquid. If you choose to use aerosol, wear a respirator and eye protection. Mask nearby surfaces to protect them from overspray.

   Laminate is brittle and breaks easily. Use caution while lifting loose edges.

Particle board and water are not good friends. Trying to "repair" water damaged particle board is not particularly feasible and the real solution is replacement.

In your case the particle board has been covered with a hard laminate product called Formica (or other similar product) that is bonded to the particle board substrate with contact cement. If you were to just want to focus on replacing the back splash it would entail removing all of the old back splash and replacing with new. Doing so does however impose a number of potential big problems. Here are some of the considerations:

1. The back splash of the countertop is likely built right into the top as an integral assembly of the substrates and then was covered with the Formica and trimmed in place with a laminate trimming router. Partial disassembly in this case would likely not be successful.
2. If there is any age to this countertop it is unlikely that you can find matching replacement laminate material in the same pattern. The manufacturers of this material come out with dozens of new patterns and colors every year to keep pace with current trends and tastes. In addition the material can change looks over time and even new material of the same pattern may look obviously different.
3. Even if the back splash can be individually removed it may become very difficult to install a new suitable substrate fastened to the wall and then having laminate installed in place. This would be due to how a laminate trimming router cannot be used on a narrow 1" top that is wedged up against the wall. If the replacement back splash was made up in the shop and then brought to the installation site there would be little choice but to try to glue it to the wall and the chances of getting a very good fit down to the existing counter top are highly unlikely. After all you would not want to see screws or nails through the back splash to hold it in place.

I can see two general repair strategies that may work for you. The first is to cut out the existing back splash and replace it with something contrasting and different. Tiles can be installed in a row across the back of the counter (in fact that is what my current 35 year old house has; laminate countertop with ceramic tile back splashes in the kitchen and laminate countertops in the bathrooms with red oak board back splash trimming).

The second strategy would be to remove all of the back splash and countertop materials and build in new replacements. A professional may very well suggest a replacement countertop material that comes pre-made with an integrated back splash and laminate that is continuous across the surface from the front edge all the way across and curved up and over the rounded edges of the back splash. If you want to retain the rectangular style like you currently have that can surely be built anew by a good craftsman but if you go that route consider using plywood as the substrate instead if particle board.

Covering a countertop with Formica laminate is a style that has really gone by the wayside in the recent decades in favor or other materials such as tile, stone, marble and other fake imitations of these. This may be a time to consider an upgrade to a more modern style.