Kinds of Underlay for the Bathroom

Wood Underlayment

• Wood is the primary material in traditional underlayment for bathrooms. Types of wood used include plywood, particleboard, hardboard and medium density fiberboard. Each of these materials may contain any of numerous wood types. Plywood consists of two wooden boards glued together while hardboard, particle board and MDF all consist of boards made of wood fibers and particles bonded with glues and other chemicals. Hardboard is the hardest of these boards, followed by MDF and particleboard. The actual qualities of any type of wood board vary depending on the manufacturer.

Problems with Wood Underlayment

• Wood bathroom floor underlayment materials exhibit various problems. Wood commonly expands and warps when exposed to a high degree of moisture, such as that found in a bathroom. Warping underlayment changes the shape of a bathroom floor and essentially voids the point of installing underlayment. MDF and hardboard may possess an exterior laminate that prevents moisture from warping the material. Even so, the laminate, glues and resins present in underlayment materials can permeate floors and ruin the color and texture of floor material.

Alternative Underlayments

• Online building resources recommend two alternatives to traditional wood-based bathroom underlayment. Tim Carter, the titular builder of the website “Ask the Builder,” recommends gypsum fiberboard, a composite material made from the mineral gypsum. These boards exhibit great strength, contain no resins or glues potentially damaging to floors and cut easily with a utility knife, making them easy to work with. Online resource “Home Time” recommends concrete backerboards for bathroom underlayment or concrete boards with fiberglass coating on each face. Concrete makes these materials very hard while fiberglass protects concrete from moisture damage.

Underlayment Compatibility

• Always take into account the adhesive or bonding material used with your floor surface before purchasing underlayment. Each type of bathroom floor, form vinyl to linoleum and ceramic tiles, requires a different type of adhesive to bond with underlayment. Not all underlayment materials work well with the bonding material required of a floor type. Always use underlayment that can successfully form a bond with your floor type and the adhesive require for use with that floor material.