Home Repair: How to Seal Laminate Flooring Expansion Gaps

Updated: Oct. 21, 2019

Block potential moisture problems

FH10MAR_SEAGAP_01-2Family Handyman
Laminate flooring can be used for wet areas like bathroom floors, but only if it's AC3 rated, with sealed expansion gaps at walls and around fixtures. Here's how to do it.

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Expansion gap details


Hold off on setting the toilet and the baseboard molding until you’ve filled the expansion gaps around room perimeters and the toilet flange with 100 percent silicone caulk.

How to Seal Laminate Flooring

Anytime you install laminate flooring in a bath, laundry room or kitchen, you should use AC3-rated flooring, leave 1/4-in. expansion gaps at the walls and fixtures, and then fill the gaps at flooring ends with 100 percent silicone caulk. It stays flexible, allowing the floor to expand, and in the event of a spill, prevents water from soaking into the laminate core. Filling the gaps can use up a lot of caulk, so buy more than you think you’ll need.

Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • Caulk gun
  • Rags

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here’s a list.

  • Silicone caulk