Ask the Experts: Substrates and Sinks for HPL

In a new series on, we have teamed up with the Formica Group Technical Team to answer some of the most common questions we receive from fabricators about our surfaces. Of course, if you have specific or unique questions, you can always reach us directly at 1-800-FORMICA (367-6422), but you may be able to find a quick answer to a common question below.

We start by examining substrate and sink options for high pressure laminate.

Question: What’s the best substrate to use with Formica® Brand Laminate? 

Answer: As HPL moves with humidity swings, it is important to choose a substrate which moves at similar rates. The industry uses Particleboard and MDF substrates in most applications as these are comprised of randomly oriented wood fibers which absorb moisture similarly to HPL. Other marginal substrates include plywood, steel and aluminum but they will move at a different rate than HPL and in the case of metals will react to temperature and not humidity. Substrates which are problematic include gypsum and similar inorganic materials due to poor bonding and variances in dimensional change and thus are not recommended. For more details about each substrate, download our substrate tech brief


Question: What are my sink options to use with Formica® Brand Laminate?

Answer: Many people are under the impression that you can only use a drop-in sink with high pressure laminate, but that’s simply not the case. You can use either traditional drop-in sinks or undermount sinks with Formica® Brand laminate. 

An undermount sink is one that’s installed underneath the countertop instead of on top like the more traditional “drop-in” style sink. It’s held in place by a strong adhesive.

Drop-in sinks, on the other hand, are literally dropped in to a pre-cut hole in the countertop and feature a thick rim around the edges. The weight of the sink is supported by the countertop.

Question: I didn’t know that you could use an undermount sink with laminate. Are there any special considerations that need to be followed for this to work properly?

Answer: Since we’re more experts on surfacing, we asked Karran to provide some guidance for using undermount sinks with HPL.

Mark Webster of Karran USA says, “To be undermounted to high pressure laminate, a sink must have an approximately 1” wide rim that is made from a resin, has been machined completely flat and meets the bowl wall at a sharp 90-degree angle.” Read more about these requirements and which Karran sink styles work best in this article

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