It is not necessary to install build up strips under laminate countertops. A leveling compound or thinset should be sufficient to provide a level surface for the countertop. If you are experiencing problems with water seepage, you may need to install a moisture barrier between the countertop and cabinets.

The short answer is no, you do not need to use build up strips under laminate countertops. However, if your countertops are particularly old or damaged, using build up strips may help to create a more seamless and even surface for your new laminate countertop to sit on.