.jpg)
San Diego's ADU boom means more homeowners are flooring a second structure for the first time, usually poured straight onto a concrete slab. That slab changes the installation math in ways a normal living room remodel never has to consider. Click lock and glue down laminate are both legitimate options, but they respond to moisture, subfloor imperfection, and rental wear in very different ways.
Getting this choice right up front saves a full floor replacement two years into a tenancy. Getting it wrong usually shows up as peaking seams, hollow sounding spots, or edges that lift the first humid summer.
What Click Lock Actually Means for Your ADU
Click lock laminate planks snap together edge to edge and float above the subfloor rather than bonding to it. The planks expand and contract as a connected sheet, which is exactly what you want over a slab that shifts slightly with temperature and moisture through the seasons. Installation is faster and cleaner, with less specialized labor and less curing downtime before the space is livable.
The tradeoff is that a floating floor needs a genuinely flat slab and a proper moisture barrier underneath, or the whole system telegraphs every imperfection. In a rental ADU where tenants may not report a small issue right away, a slightly uneven click lock installation can turn into a visible ridge line faster than it would in an owner occupied home.
What Glue Down Actually Means for Your ADU
Glue down laminate bonds directly to the slab with adhesive, creating a rigid connection that resists shifting under heavy or constant foot traffic. This matters more than people expect in an ADU that will see daily use from a tenant, an aging parent, or a long term renter rather than occasional guest traffic. A bonded floor also tends to feel more solid underfoot and produces less of the hollow sound some click lock installations have.
The catch is that glue down is unforgiving of slab moisture. Adhesive failure from trapped moisture is one of the most common laminate callbacks we see in coastal San Diego, and it is not something a homeowner can diagnose by eye before installation. This is where a moisture reading on the actual slab, not a general assumption about the neighborhood, decides the outcome.
Slab Moisture Changes the Calculation
Every ADU slab is its own case. A newly poured slab in Rancho Bernardo behaves differently than a decades old slab in a coastal zone like La Jolla or Del Mar, and soil composition, drainage, and even the direction the ADU faces all play a role. This is why a real moisture test matters more than the general reputation of the neighborhood.
Skipping this step is the single biggest reason laminate installations fail early, regardless of which method you choose. A five minute test before installation is far cheaper than tearing out a floor that failed inspection with a tenant already moved in.
Which Installation Method Wins for a Rental ADU
For most San Diego ADUs being used as rental units, click lock with a proper vapor barrier is the more forgiving and more repairable choice, since individual planks can be replaced without disturbing the whole floor. For an ADU intended as a permanent multigenerational suite with constant daily traffic, glue down often delivers a more solid, quieter feel worth the extra prep work.
Neither choice is universally correct, which is exactly why this decision should not be made off a product label alone. The right call depends on your specific slab, your intended use, and how the space will actually be lived in day to day.
Every ADU project America's Best Flooring handles starts with an actual look at the slab, not a guess. If you are planning flooring for an ADU anywhere across Carmel Valley, La Jolla, Del Mar, Poway, Coronado, Rancho Santa Fe, Solana Beach, East Lake, Chula Vista, La Mesa, Encinitas, Carlsbad, Cardiff, San Marcos, Escondido, Santee, El Cajon, Rancho San Diego, and Ramona, CA, our team can test the space and walk you through which laminate flooring system fits your project before you buy a single plank. Visit us at San Diego, CA or contact us to schedule a walkthrough.
