Water or moisture-damaged laminate is a serious problem rarely covered by your flooring manufacturer's warranty. If the damage is extensive and the quality of the original laminate is poor, replacing the entire floor is a practical option. A repair involves lifting the floor, fixing the moisture problem, drying the area, replacing the damaged planks and reinstalling the floor. With care, a laminate of 8mm or thicker can withstand a lot of handling, and if matching replacement planks are available, a repair is worth the try.
Puffy, swollen and raised plank edges clearly identify water damage in a laminate floor. Water-damaged laminate cups and buckles due to uneven moisture distribution throughout the plank thickness. Typically, damaged laminate is wetter on the underside, so the moisture isn't visible to the eye. As the planks swell and compress together underneath, the edges are forced upwards, damaging the locking mechanism between the planks that hold the floating floor in place, causing it to buckle.
With the exception of floods, determining the source of moisture is tricky. If the damage is confined to a small space, the problem may be the result of pet urine, incorrectly acclimatised planks, a spill that was left standing for too long or a few improperly sealed joints in a moist area, such as a bathroom. If the entire floor is cupping, you may have a slow leak from a pipe or appliance. Poor maintenance practices, such as regular wet mopping, might be at fault, or the laminate may have been installed over an uncured concrete subfloor.
Do not attempt to replace any laminate until the source of the moisture is identified and remedied and the area is completely dry. If in doubt, consult both a plumber and a flooring installer. Plumbers often use moisture meters to track down the origin of leaks while a flooring installer can recommend the best way to test the moisture level in concrete if you suspect a subfloor problem. Once the issue is resolved, use fans to further dehydrate and prevent mould.
If the problem area is small and you're highly skilled, you can use a circular saw to remove the damaged laminate and install replacement planks, though this will likely involve some trimming, shaving and gluing and is an approach best implemented by professionals. Otherwise, gently lifting the floor, removing and replacing the damaged planks and reinstalling in the order of removal is your best bet. If you need to replace the entire laminate floor, follow the manufacturer's instructions closely.